Tomos A3M, A3K, A3MS, A3ML Workshop Manual

Tomos

Mopeds

Owners

Workshop

Manual

Pete

Shoemark

Models

covered

A3K. 49cc. Introduced

November

1982

A3M. 49

cc.

Introduced

August

1984

A3MS. 49cc. Introduced

July

1984

A3ML.

49cc. Introduced

July

1984

ISBN 1 85010

062

4

© Haynes Publishing Group

1984

All rights

rnerwd

. No

put

of this

book

may

be

reproduced

or

transmitted

in

any

form

or

by

any

means, electronic

or

mechanical. i

ncluding

photocopying,

recording

or

by

any information

sto..-ge

or

retriewil

system

, wi

thout

permission

in

writing

from

the

copyr

ight

holder

.

Printed

in

England

HAYNES PUBLISHING GROUP

SPARKFORD

YEOVIL

SOMERSET BA22 7JJ ENGLAND
HAYNES PUBLICATIONS

INC

861 LAWRENCE

DRIVE

NEWBURY

PARK

CALIFORNIA

91320 USA

Britlall lib••rv Ce1el09uinv in

Publicelion

D•t•

St.o..mA P

ete

Tomas

lnO!l<'ds

owners

WOO.shoP manual,

I M

ope<l

s - ll1aln

1en

• nce and repaii - Tomos moued

1. nu.

529 2e· 12 T

l45

3 T6

ISBN

1-85010--062~

Our thanks are

due

to

Dwek

International

Limited

. the

UK

importer and di

stributor

of

the

Tomos

range. and in

particular

to

Stewart

C Bronstein

of

the

above

company

who

arranged the

loan

of

the machine used in

the

woritshop

project. provided

the

technical

information on

the

models

covered

by

the

manual

and checked the

About this manual

conten

ts

of

the

manual

for

technical

accuracy.

The

Avon

Rubber

Company

supplied information

on

tyre careanc

fitting

. and

NGK

Spark

Plugs

(UK)

Ltd

provided

informat

ion

on

plug

maint

enance a

nd

electrode

conditions

.

Contents

Page

Acknowledgements

2

About

this

manual

2

Introduction

to

the Tomos mopeds

6

Model

dimensions

and

weights

6

Ordering spare parts 7

Safety

first

I 8

Tools and

working

facilities 9

Choosing and

fitting

accessories

12

Fault diagnosis

14

Routine maintenance

21

Chapter 1 Engine and transmission

26

Chapter 2 Fuel system and lubrication

49

Chapter 3

Ignition

system

54

Chapter 4 Frame and suspension

59

Chapter 5

Wheels

, brakes and tyres

68

Chapter 6 Electrical system

75

Wiring

diagrams

79

Conversion

factors

81

Index

82

Left-hand

view

of

the

A3K

model

Left-hand

view

of

the

A3M

model

~-------------------------------------------------------------·

Left-hand

view

of

A3ML

model

Right-hand

view

of

A3MS

model

Introduction

to

the

Tomos mopeds

The three

Tomos

models currently imported

into

the

UK

share the

same basic chassis and engin

e/

transmission unit.

with

variations in

equipment and accessory

fitments

.

The base

model

of

the range is the

A3K. It

is powered

by

a single-

cylin

der air-cooled

two

-stroke engine driving through a

two

-speed

auto

mat

ic transmission.

The engine/transmission unit is mounted

in

a semi-monocoque

spine frame. fabricated from steel pressings and incorporating the fuel

tank. Fro

nt

suspension is

by

undamped telescop

ic

forks,

whilst

rear

suspension is provided

by a swinging

arm

controlled by coil-spring

suspension

unit

s.

Front and rear

wheels

are

of

the

wire

-spoked type with c

hromium

·

plated steel

rims and

tubed

tyr

es. If·

The

A3MS

Is largely

similar, but

Is distinguished

by

8

~

eel

contained turn signal system, a larger seat and a plated

tubu~

ar

1

5

has

luggage rack. The

A3ML

model Is similar

to

the MS.

1

~

b

lack

redesigned rear suspensi

on

units

with

e>Cposed

springs

and

ma

cast alloy wheels.

_IVl_o

__

d_e_l_d_im

__

e_n_s_io_n_s

__

a_n_d

__

-w_e_i~g~h_t_s

______________

__

Overall

length

.................................................................................... .

1

640

mm

(64

.6 in)

Wheelbase

.......

...

....

...

..................

................

.............................

....

...... .

1080

mm

(42.6 in)

Dry

weight

.....

....

........................

....................

...

.............

...

.................

. .

44

kg

(97

lbs)

Carrying

capacity

.......

...

...................

...

..........

......

........

....................

.. .

1 12.6 kg

(248

lbs)

Ordering spare parts

When ordering spare parts for

any

Tomos model

it

is advisable to

deal direct

with

an official Tomos dealer

who

will be able to supply
most items ex-stock. Where parts have to be ordered, an authorised
dealer

will

be able to obtain them

as

quickly

as

possible. The engine
and frame numbers must always be quoted in full. This avoids the risk
of

incorrect parts being supplied and is particularly important where

detail modifications have been made in the middle

of

production runs.

In some instances

it

will be necessary for the dealer to check

compatibility

of

later parts designs

with

earlier models. The frame

number is stamped

on

a plate riveted to the frame and the engine

number on a raised boss on the crankcase

Freme number la

stamped

Into

the

frame

near

the

gearbox filler plug

It

is recommended

that

genuine Tomos parts should

be

used

Although pattern parts are often cheaper, remember

that

there is no

guarantee that they are

of

the same specification as the orig·nal, and

in some instances they

may

be positively dangerous

Note

also

that

the use

of

non-standard parts

may

invalidate the warranty

in

the

event

of

a subsequent failure.

Some

of

the more expendable parts such as oils, greases, spark
plugs, tyres and bulbs, can safely be obtained from auto accessory
shops. These are often more conveniently positioned and may apen
during weekends.

It

is also possible

to

obtain parts

on a mail

order

basis from specialists

who

advertise in the

moto

rcycle magazines.

,,

.

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the

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that

the

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liance

trfY

e

aJtt,.d

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to

Ill

plug

and

that. wher11

nece15ary. it is

~oot

and

141

'

(groundodl. Do not u10 1uch

applian

ces

In

damp condiflonJ .

"

-wi

~~

b

·

~ ~

·

ewor11

of creating a 1p

11rk

or applvl

ng

e11

ce11ive

heat

in

fuol or fuol

vap

our.

Ignition

HT

voltage .

parU

iJ

A

1111vore

el11ctrlc shock can

r111ult from

tou

ching

~rt.a·~

(lllllli<i9

tho

Ignition 1y11om, 1u

ch

111 th11

HT

lead

s.

when

the

eng~!

;,,wJa:P'

or bolng c

rankod

, p

ortlcul11rly

If components are

damP or

ed

1

M !ff

1

•

do

foctl

v11. Whore ""

oloctronlc Ignition 1y!ltem 1•

fitt

'

vo

lt8gt

11 much

hlgh11r

ond could

prove

fatal.

Tools

and

working

facilities

The first pri

ority

when

undert3king maintenance

or

repa

ir

work

of

any sort

on a motorcycle

is

to

have a clean. dry,

well

-lit

work

ing area.

Wo

rk carried

out

in

peace and

quiet

in

the

well

-ordered atmosph e

re

of

a good

workshop

will

give

more

satisfac

tion

and much

better

results

than can usually

be

achieved in

poor

working

conditions. A good

workshop

must

have a clean

flat

workbench

or

a solidly constructed

table

of convenient

working

height

. The

workb

ench

or

table sho

uld

be

equipped wi

th

a vice

which

has a jaw

openi

ng

of

at

least 4 in (

100

mm). A set

of

jaw

covers

should

be

made

from

soft

metal such as

aluminium

alloy

or

copper. or

from

wood

. These covers will minim

ise

the

marking

or

damaging

of

soft

or

delicate

components

whi

ch

may

be

clamped in

the

vice. Some clean, dry, storage space

will

be required

for

tools, lubricants and

dismantled components. It

will

be

necessary

during a major

overhaul

to

lay

out

engine/gearbox components

for

examination and

to

keep

them

where

they

will

remain undisturbed

for

as long as is necessary.

To

this

end

it

is recommended

that

a supply

of

metal

or

plastic containers

of

suitable size is collected. A supply

of

clean.

lint

-free, rags

for

cleaning purposes and some newspapers,

other

rags,

or

paper

towels

for

mopping

up

spillages should also be

ke

pt. If

working

on

a hard concrete

floor

note

that

both

the

floor

and

one's knees can

be

protected

from

oil spillages and

wear

by

cutting

open a large cardboard

box

and spreading

it

flat

on

the

floo

r under the

machine

or

workbench. This

also

helps

to

provide some

warmth

in

wi

nter

and

to

prevent

the

loss

of

nuts

, washers, and

other

tiny

components

which

have a tendency

to

disappear

when

dropped on

anything

other

than a perfectly

clean,

flat

, surface.

Unfortunately, such

working

conditions

are

not

always available

to

the home mechanic.

When

working

in

poor

conditions

it

is essential

to

take extra ti

me

and care

to

ensure

that

the

components

being

worked

on are

kept

scrupulously clean

and

to

ensure

that

no

components

or

tools are lost

or

damaged.

A

selection

of

good

tools

is a fundamental requirement

for

anyone

cont

e

mplating

the maintenance and repair

of a motor

vehicle. For

the

own

er

who

does

not

possess

any, their

purchase

will

prove a

considerable expense,

offsetting

some

of

the

savings made by

doing

-

it

-yourself.

However

, provided

that

the

tools

purchased are

of

good

quality,

they

will

last

for

many

years and prove an extremely

worthwhile

investment

.

To help

the

average

owner

to

decide

which

tools

are

neede~

to

carry

out

the

various tasks

detailed

in

this

manual,

we

have compiled

three lists

of

tools under

the

following

headings:

Maintenance

and

minor

repair, Repair

and

overhaul, and Specialized. The

newcomer

to

practical mechanics shou ld start

off

with

the simpler

jobs

around the

vehicle. Then, as his confidence and experience

grow

. he can

undertake more

difficult

tasks, buying extra tools as and

when they are

needed.

In

this

way

, a

Maintenanca

and minor

repair

tool

kit can be

built-up

into

a Repair

and

overhaul

tool

kit

over a considerable period

of

time

without

any

major

cash outlays. The experienced

home

me

chanic

will

have a

too

l kit good e

nough

for

most

repa

ir

and overhaul

procedures and

will

add

tools

from the

specialized category

when

he

feels the expense is justified

by

the

amount

of

use these

tools

will

be

put to.

It

is

obv

iously

not

possible

to

cover

the

subject

of

tools

fully

here.

For those

who

wish

to

learn more

about

tools and

their

use

the

re is a

book

ent

itl

ed

How

to

Choose

and

Use

Car Tools availabl e

from

the

publis

hers

of

this

manual.

Although

, as

its

title

implies,

this

publi

cation

is directed at car

owners. the

information

given is equally applicable

to

mo

torcycle owners.

It

also provides

an

introduction

to

basic

workshop

practice

whi

ch

will

be

of

int

erest

to a home

mechanic worki

ng

on

any

type

of

motor

vehicle.

As

a general rule.

it

is

bett

er

to

buy

the

more

expensive, good

quality

tool

s. Given reasonable use,

such

tools

will

last

for

a very long

time

, whereas

the

cheaper,

poor

quality,

item

will

wear

out

faster and

need

to

be renewed

more

often, thus

nullifying

the

orig

inal saving.

There

is

also

the

risk

of a poor

quality

tool

breaking

while

in use.

causing

personal injury

or

expensive damage

to the

component

being

worked

on.

It

should be

noted, however, that

many

car

accessory

shops and

the

large

department

stores sell

tools

of

reasonable quality

at

competitive

prices. The best example

of

this

is found

with socket

sets,

where

a mediu

m-priced

socket set wi

ll

be

quite

adequate for the

home owner

and

yet

prove less expensi

ve

than a selecti

on

of

individual

sockets and accessories.

This

is because individual pieces are usually

only available

from

expensive,

top

quality

. ranges and

whilst they are

undeniably good, it should be remembered

that

they

are intended

for

professional use.

The basis

of

any

toolk

it is a

set

of

spanners.

While

open-ended

spanners w i

th

the

ir

slim

jaws.

are useful

for worki

ng

on

awkwa

rdly-

positioned

nuts, ring

spanners have advantages

in

that

they

grip the

nut

far

more

positively. There is less risk

of

the

spanner slippi

ng

off the

nut

and

damaging it,

for

this

reason alone ring spanners are

to

be

~referred

.

Ideally,

the

home

mechanic

should acquire a set

of

each.

but

if

expense rules this

out

a set

of combination

spanners (open-ended

at

one end and

with a ring

of

the

same

size at

the other) will provide a

good

compromise. Another

item

which

is

so

useful

it

should be

10

Tools

and

wortting

facilities

considered an essential

requ

irement

f~

an

~e

mecha

c is a set

of

soc;ket soanners

These

a

re

ava~able

m _a van

ety

of

d

ri

e size

It

Is

ecommended

th

at

the

f-i

nch

dm

<e

type

is

purchased to

beg

m

th

as

1

linough bul er and

mor

e e

x:pe

nsive than the !

-inc

h

type

,

the

larger

:i

ze

rs far

moie

common and will accept. a greater variety

of

torque

wrenchel

e~en:sion

pi

eces a

od

soclt

et size

s. The

socket

set

should

compnlloC

sockets of sizes

between 8 and

24

~m

.

a re ersible ratch

et

d

. an extension bar

of

about 10 i

nch

es m length. a spark plug

mre. _

_.

I I

'.

0

socket wi

th

a rubber inse

rt

. a

•ou a un

versa

JOm

t. ther

attachments

can

be

added

to

the set

at

a l

ater

date

.

Maintenance

and

minor

repair

tool

kit

Sf!f

of

spannf!

rS

8 -

24

mm

Sf!t

of

sockets

and

attachments

Spark

plug

spanner wi

th

rubber insert

-

10

. 1 2. or

14

mm

as appropn'ate
Adjustab

le spanner

c-spanner/pin

spanner

Toroue wrench (

same

size dri

ve

as

sockets

}

Set

of

scre

wdrivttrs (flat

blade}

Set of scrtt

wdrivttrs

(c

ross-head}

Se

t of

All

en lceys 4 -

10

mm

Im

pact scre

wdr

iver

and

bits

B

all pein hammttr - 2

lb

Hacksaw (junior}

Self-l

ocki

ng plittrs -

Mole gri

ps

or vice grips

Pliers - c

ombination

Pliers - nttedle nose

Wirt! brush (

small

}

S

oft-br

istlttd brush

Tyre

pum

p

Tyre

prtt

ss

ure gaugtt

Tyre

tread

depth

gauge

O

il

can

F

in

e emery

cloth

Funn

el (medium

size)

Drip

tr

ay
Set of feeler gauges
Strobe timi

ng light

Continuity tester

(dry

battery

and

bulb)

Solderi

ng iron

and

solder

Wi

re

stripper

or

craft

knife
PVC insulating tape
As

sortment

of

split

pins. nut

s.

bolts. and washers

Repair

and

overhaul

toolkit

The tools in this list are virtually essential for anyone undertaking

major repairs

to

a motorcycle and are additional

to

the tools listed

above. Concerning

Tone

driver

bits. Tone screw

s are enc

ount

ered on

some of the more modern machines where their use is res

tri

cted

to

fastening certain components inside the engine/gearbox

unit. It

is

therefore recommended

that

if

Tone

bits cannot be borr

owed

from

a

local

dealer. they are purchased individually as

the

need arises. They

are not in regular use

in

the

motor trade and

will therefore on

ly

be

:t\1!>;1-,.h

ln

:n

..,_

....

....

: ... 1

:-• •--

• - •

Will!

brush fla

rge

J

Soft ·re

brush

(similar to thos

e used for

cleaning

sued

e

shoes}
S

hee

r of

pla

te glass

Hac

ksaw

(/11rgtt}

Valve

grinding tool

Valve g

rind

ing compound (coarse a

nd fine}

St

ud

extract

or

set

(E-Z

out}

Specialized

tools

Th

is

is

not

a list

of

the

tools

mode

by

the ma chine's manufactu

rer

to

carry o

ut

a specific task on a

limit

ed range

of

models. Occasional

references are

ma

de

to such tools in the text

of

this manual ond. In

general. an alternative met

hod

of carrying o

ut

the task w

itho

ut

tho

manufacturer's t

oo

l is given where possible. Tho tools me

nti

oned In

th

is list are those

whi

ch ero

not

used regularly and are oxpenslvo to

buy

in view of their infrequ e

nt use. Wh

ere this

is

the case it may

be

possible

to

hire or bor

row

the tools

against a deposit from a local

dea ler

or

tool hire shop. An alternative is for a group of friends

or

a

motor

cycle club to join in the purchase.

Piston ri

ng

comp

ressor

U111versal

beari

ng pull

er

Cylinder bore h

oning attachment (for

elecrric

drill)

M

icror

net

er

set
Vernier calipers
Dial gauge set
Cylinder

co

mpression gau

ge

Vacuum

gauge set
Mulrimeter
Dw

ell merer/racho

met

er

Care

and

maintenance

of

tools

Whatever the quali

ty

of the tools

pur

chased, they

will

last much

longer if cared for.

Th

is means in practice ensuring

that a too

l Is used

for its

in

tended purpose:

for

example screwdrivers should

not

be used

as

a substitut

e for a centre

pun

ch.

or

as

chisels. Always remove dirt or

grease and any metal partic

les but

remember

that a light

film

of oil will

preve

nt rusting if the tool

s are infrequently used. The common tools

can be kept together in a large box

or

tray

but the mo

re

delicate. and

more expensive,

items

shou ld be stored separately where they

cann

ot

be damaged. When a

tool

is damaged or

worn

out

, be sure to renew

it

immediately.

It

is false eco

nomy

to continue

to use a

worn

spanner

or

scre

wdr

iver

whi

ch may sl

ip

and cause expensive damage to the

component be

ing wo

rked on.

Fastening

systems

Fastener

s.

basica

lly

, are

nut

s, bol

ts

and screws used

to

hold two

or

more p

art

s together. There are a

few thi

ngs

to

keep in mind when

working

with

fasteners.

Almost

all

of

them

use a locking

device of

som

e type;

eithe

r a lock was

her

. lock

nut

, locking

tab

or thread

adhesive. All

th

readed fasteners should be clean. straight. have

un

dama

ged threads and

undama

ged co rners on the hexagon h

ead

Spanner

size comparison

Jew

gap

(in)

0.

250

0.

276

0.

313

0.

315

0.

344

0.

354

0.

375

0.

394

0.

433

0.

438

0.

445

0.

472

0.

500

0.

512

0.

525

0.551

0.

563

0.591

0.

600

0.625

0.

630

0.

669

0.

686

0.

709

0.

710

0.

748

0.

750

0.

813

0.

820

0.

866

0.

875

0.

920

0.

938

Spenner

eize

t in AF

7

mm

i\

in

AF

8

mm

}lin

AF; t in

Whitworth

9

mm

i In AF

10

mm

11

mm

4

in

AF

.\

in

Whitworth

; t in BSF

12

mm

tin

AF

13

mm

t in

Whitworth

:

t\

in BSF

14

mm

i\

in AF

15

mm

i in

Whitworth

: i in BSF

i in AF

16

mm

17

mm

ij

in AF

18

mm

i

in

Whitworth

: 4 in BSF

i9

mm

tin

AF

Ii in AF

4 in

Whitworth

; t

in

BSF

22

mm

tin

AF

t in

Whitworth

; i\ in BSF

II

in AF

Standard

torque

settings

Jaw

gap

(in)

0.

945

1.

000

1.

010

1.

024

1.

063

1.100

1.

125

1 .181

1.

200

1.250

i .

260

1.

300

i .

3i3

i .

390

1.

417

1.

438

i .

480

1.

500

i .

575

i .

6i4

i .

625

1.670

1.688
i .8

ii

i .

813

i .

860

1.875

i .

969

2.

000

2.

050

2.i65

2.

362

Spanner

elze

24

mm

1 in AF

A in

Whitworth

; i In BSF

26

mm

1~

in AF;

27

mm

A in

Whitworth

;

ij

in BSF

1-f

in

AF

30

mm

ij

in

Whitworth

; t

in

BSF

lt

in AF

32

mm

t in

Whitworth

; i in BSF

11\

in

AF

Ji

in Whi

tworth

;

II

in BSF

36

mm

i4 in AF

t in

Whitworth

; i in BSF

1t

in AF

40

mm

: Ii

in

Whitworth

4i

mm

it

in AF

i in

Whitworth; it

in

BSF

1ij in AF

46

mm

i!j

in

AF

it

in

Whitworth; if

in

BSF

it

in

AF

50

mm

2 in AF

ii

in

Whitworth; ii

in

BSF

55

mm

60

mm

Specific torque settings

will

be found at

the

end

of

the specifications section

of

each chapter. Where

no

figure is given.

bolts

should

be

secured according

to

the

table

below

.

Fastener

type

(thread diameter)

5mm

bolt

or

nut

6

mm

bolt

or

nut

8

mm

bolt

or

nut

10

mm

bolt

or

nut

12

mm

bolt

or

nut

5

mm

screw

6

mm

screw

6

mm

flange

bolt

8

mm

flange

bolt

1 0

mm

flange

bolt

kgf

m

0.

45

- 0.6

0.8

- 1.2

1.8 -2.5

3.0 - 4.0

5.0

- 6.0

0

.3

5 - 0.5

0.7

-

i.

i

i .0 - i .4

2.4 - 3.0

3.0

- 4.0

lbf

ft

3.5 -

4.5

6 - 9

i3 -i0
22 -29
36 -43

2.5 - 3.6
5 - 8

7 -

io

i7 -22
22

-

29

r

,~

Choosing and fitting accessories

The range

of

accessories available

to

the

modern

motorcyclist

is

almost as varied and

bewildering

11

the

range

of

motorcycles

. This

Sectio

n is intended

to

help

the

owner

in

choosing

the

correct

equlpment for his needs

and

to

avoid some

of

the

mistakes

made

by

many riders

when

adding accessories

to

their

machines. It

will be

evident that

the

Section can

only

cover the subject

in

the

most

general

terms and so

It

is

recommended that

the

owner

. havi

ng

decided

that

he wants

to

fit.

for

example. a luggage rack

or

carrier. seeks t

he

adv

ice

of several local deelers end

the

owners

of

similar

machin

es. This

will

gi

ve

a good idea

of

what

makes

of

carrier are easily available . a

nd

at

what price. Talking

to

other

owners

will

give

some

insight

into

the

drawbacks or

good

points

of

any one make. A

walk

round

the

motorcycles

in

car

parks

or

outside a dealer

will

often

reveal the same

sort

of

information.

The first priority

when

choosing accessories is

to

assess exactly

what

one needs.

It is, for example, pointless

to

buy a large

heavy-duty

carrier

which

is designed

to

take

the

weight

of

fully laden panniers and

topbox when all you need

is

a place

to

strap

on

a set

of

waterproofs

and a lunchbox when

going

to

work.

Many

accessory manufacturers

have ranges

of

equipment

to

cater for the individual needs

of

different

riders and

this

point

should

be

borne

in

mind

when

looking

through

a

dealer's catalogues. Having decided exactly

what

is

required and the

use

to

which

the accessories are

going

to

be

put.

the

owner

will

need

a

few

hints

on

what

to

look

for

when

making

the

final choice. To

this

encl

the Section

is

now

sub-divided

to

cover

the

more

popular

accessories

fitted. Note

that

it

is

in

no

way

a customizing

guide, but

merely seeks

to

outline

the

practical considerations

to

be taken

into

account

when

adding aftermarket equipment

to a motorcy

cle.

Fairings

and

windscreens

A fairing

is

possibly

the

single.

most

expensive, aftermarket

item

to

be fitted

to

any motorcycle and, therefore, requires

the

most

thought before purchase. Fairings can be divided

into

two

main

groups: front fork mounted handlebar fairings and

winds

creens, and

frame mounted fairings.

The first group, the

front

fork

mounted fairings, are

becoming

far

more popular than was once the case, as they offer several advantages

over

the

second group. Front fork mounted fairings generally are much

easier and quicker

t?

fit,

involve less modification

to

the motorcycle,

do

not

as a rule restrict the steering lock,

permit a wider

selection

of

handlebar styles

to

be used, and

offer

adequate protection

for

much

less money than the frame mounted type. They are also

lighter

can be

swapped easily

~etween

different motorcycles, and are availa0ble

in

a

much greater variety

of

styles. Their main disadvantages are

that

they

do

not

offer

as much weather protection .as

the

frame

mounted

types,

rarely offer any storage space, and,

1f

poorly fitted

or

naturally

incompatible, can have an adverse effect

on

the stability

of

the

motorcycle.

The second group,

the

frame mounted fairings, are secured

so

rigidly

to

the

main

frame

of

the

motorcycle that they can offer

8

substantial

amount

of

protection

to

motorcycle and rider

in

the

event

of

a crash. They

~ffer

a.lmost

comp~ete

protectlo~

from

the

weather

and,

if

double-skinned

in

construction, can provide a great deal

of

useful storage space. The

'?~ling

of. peace, quiet and complete

relaxation encountered

when

riding behind a good full fairing has

to

be

experienced

to

be believed. For this reason full fairings are considered

essential

by

most

to

·

11

uring motorcyclists and by many people

who

ride

: year

roun~

.

The main. disadvantages

of

this type are that fitting can

ake a

long

time. often

involving removal

or

modification

of

standard

motor

cycle components, they restrict the steering

lo.ck

and they can

add

up

to

about

40

lb

to

the weight

of

the machine They do

not

usually affect the stability

of

the machine

to

any great

e~ent

once the

front tyre pressure and suspension have been adi·usted t
f

. o compensate

or

the

e~tra

w?1ght, but can be affected

by

sidewinds.

The.

f1~st

thing

to

look

!?r

when

purchasing a fairing is the quality

of

the fittings. A

good

famng

will

have strong, substantial brackets

c.onstructed from heavy-gauge tubing; the brackets must be shaped

to

fit the frame

or

forks evenly so that the minimum

of

stress is imposed

on the assembly

when

it

is bolted

down

. The brackets should

be

properly painted

or

finished - a nylon coating being the favourite

of

the

better manufacturers - the nuts and

bolts

provided should

be

of

the

same thread a

nd

size standard as

is

used

on

the

motorcycle and

be

properly plated. Look also

for

shakeproof locking nuts or locking

washers

to

ensure

that

everything remains securely tightened down.

The fairing shell

is

generally made from one

of

two

materials:

fibreglass

or

ABS

plastic. Both have their advantages

and

disadvantages,

but

the

main

consideration

for

the owner is that

fibreglass

is

much easier

to

repair

in

the

event

of

damage occurring

to

the fairing.

Whiche

ver material

is

used, check that

it

is properly

finished inside as

well

as out,

that

the

edges are protected by

beading

and that

the

fairing shell

is

insulated from vibration by the

use

of

rubber

grommets

at

all

mounting

points

. Also be careful

to

check

that

the windscreen is retained

by

plastic

bolts

which

will

snap

on

impact

so that

the

windscreen

will

break

away

and

not

cause personal i

njury

in

the event

of

an

accident.

Having purchased your fairing

or

windscreen, read the

manufac

-

tur

er's

fitting

instructions very carefully and check that you

have

all

the

necessary brackets and

fittings

. Ensure

that

the

mounting brackets

are

located correctly and

bolted

down

securely.

Note

that

some

manufac

-

turers use hose clamps

to

retain

the

mounting brackets;

these

should

be

dis

carded as

they

are convenient

to

use

but

not

strong

enough

for

the task. Stronger clamps should

be

substituted; car

exhaust

pipe

clamps

of

suitable size

would

be

a good alternative.

Ensure

that

the

front

forks can turn

through

the

full steering lock available wit

hou

t

fouling

the

fairing.

With

many

types

of

frame-mounted fairing the

handlebars

will

have

to

be

altered

or

a different type fitted

and

the

steering lock

will

be restricted

by

stops provided

with

the

fittings

.

A

l~

check

that

the

fairing does

not

foul

the

front

wheel

or

mudguard

.

in

any steering position

under

full

fork

compression. Re-route

anv

cabl~s

.

brake pipes

or

electri~I

wiring

which

may

snag

on

the fairin.g

and

ta

~

great

care

to

protect

all electrical connections, using insulating tape.

the

manufacturer's instructions are

followed

carefully

at

every

stage

"

1

.

0

be

h t

hydrau

1c

serious problems should

be

encountered. Remem r t . 8 d

and

pipes

that

have been

dis

connected

must

be

carefully .re-

t1ghten

e

the

hydraulic system purged

of

air

bubbles

by

bleeding.

k.

a

Two

things

will

become immediately apparent when .

ta

~n~he

motorcycle

on

the

road

for

the

first

time

with

a fairing - the

ftrs~

/:;nd

tendency

to

underestimate

the

road speed because

of

the

lack

.1 ne

pressure

on

the

body. This

must

be very carefully watched unti

~ng

has

grown

accustomed

to

riding behind

the

fairing. The

second 1 t>ut

is the alarming increase

in

engine noise

which

is an

u~fortu

nate

and

in

evitable by-product

of

fitting

any

type

of

fairing

or w1.

ndscreen.ases

is

caused

by

normal engine noise being reflected. and in

some

c

amplified,

by

the

flat

surface

of

the

fairing.

Choosing

and

fitting

accessori•

13

Luggage racks

or

carriers

Carriers are possibly

the

commonest item

to

be

fitted

to

modem

motorcycles. They vary enonnousty

in

size. carrying capacity, and

durability.

When

selecting a carrier. always loolt for one which Is made

specifically

for

your machine and

which

is

bolted

on

with

as

few

separate brackets as poasible. The universal-type carrier,

with

it.a

man

of

brackets and adaptor pieces.

will

generally prove

too

weak

to

be

of

any real use. A good carrier should

bolt

to

the main frame . generally

using the

two

suspension

unit

top

mountings and a mudguaro

mounting

bolt

as attachment points. and have

its

luggage platform as

low

and

as

far forward as possible

to

minimise the effect

of

any load

on

the machine's stability. Look for good

quality

, heavy gauge tubing.

good

welding and good finish. Also ensure that the carrier does

not

prevent opening

of

the seat. sidepanels

or

tail compartment. as

appropriate. When using

a carrier.

be

very careful

not

to

overload it.

Excessive

weight

placed so high and so far

to

the rear

of

any

motorcycle

will

have an advenie effect

on

the machine·s steering and

stability.

Luggage

Motorcycle luggage can

be

grouped under

two

headings: soft and

hard. Both types are available

in

many

sizes and styles and have

advantages and disadvantages

in

use.

Soft luggage is

now

becoming very popular because

of

its lower

cost and its

versatility.

Whether

in

the

form

of

tankbags, panniers.

or
strap-on bags. soft luggage requires in general no brackets and no
modification

to

the motorcycle. Equipment can be swapped easily

from one motorcycle

to

another and can be

fitted

and removed in

seconds.

Awkwardly

shaped loads can easily be carried. The disadvan-

tages

of

soft luggage are

that

the contents cannot be secure against

the

casual

thief

. very

little

protection

is afforded in the event

of

a crash.

and

waterproofing is generally

poor

. Also.

In

the case

of

panniers.

carrying capacity is restricted

to

approximately 1 O lb. although this

amount

will

vary considerably depending on the manufacturer·s

recommendation.

When

purchasing soft luggage. look for good quality

material. generally vinyl

or

nylon,

with

strong. well-stitched

attachment points.

It

is always useful

to

have separate pockets.

especially

on tank bags,

for

items

which

will

be needed on the journey.

When purchasing a tank

bag, look

for

one which has a separate.

well-

padded, base. This

will

protect

the tank·s paintwork and permit easy

access

to

the

filler

cap

at

petrol stations.

Hard

luggage is confined

to

two

types: panniers, and top boxes

or
tail trunks.

Most

hard luggage manufacturers produce matching sets

of
these items.

the

basis

of

which

is generally

that

manufacturer's own

heavy-duty

luggage rack. Variations on this theme occur in the form

of
separate frames for the

better

quality panniers. fixed

or

quickly­detachable luggage, and in size and carrying capacity. Hard luggage
offers a reasonable degree

of

security against

theft

and good

protection against

weather

and accident damage. Carrying capacity is

greater than

that

of

soft

luggage, around 1 5 -

20

lb

in the case

of

panniers, although top boxes should never

be

loaded

as

much as their

apparent capacity

might

imply

. A

top

box should

only

be used for

lightweight items. because one

that

is heavily laden can have a serious

effect on the

stability

of

the

machine. When purchasing hard luggage

look

for the same good points as mentioned

under

fairings and

windscreens.

ie

good

quality

mounting

brackets and

fittings

, and

well-

finished fibreglass

or

ABS

plastic cases. Again as

with

fairings, always

purchase luggage made specifically

for

your motorcycle, using as

few

separate brackets as possible,

to

ensure

that

everything remains

securely bolted

in

place.

When

fitting

hard luggage. be careful

to

check

that the rear suspension and brake operation

will

not

be impaired in

any

way and remember

that

many pannier

kits

require re-siting

of

the

indicators. Remember

also

that

a non-standard exhaust system may

make fitting

extremely difficult.

Handlebars

The occupation

of

fitting

alternative types

of

handlebar is

extremely popular

with

modern motorcyclists,

whose

motives

may

vary

from the purely practical. wishing

to

improve the

comfort

of

their

machines.

to

the purely aesthetic, where form Is

more

important than

function. Whatever the reason, there are several considerations

to

be

borne in

mind

when changing

the

handlebars

of

your machine.

If

fitting

lower bars check carefully

that

the

switches and cables

do

not

foul the

Petrol

tank

on full lock and

that

the surplus length

of

cable. brake pipe,

and

electrical

wiring

are smoothly and

tidily

disposed of. Avoid

tight

kinks In cable or brak.e pipes which

will

produce

stiff

cont1ols

or

the

pnimature and disastrous failure

of

an

overstrened

component.

If
necessary. remove the petrol tank and re-route the cable from the
engln gearbox

unit

upwaros. ensuri

ng

smooth gentle curves are

produced.

In

extreme cases.

it

will

be

neceuary

to

purchase a shorter

brake pipe

to

overcome this problem.

In

the c11e

of

higher handlebars

than standard

it

will

almost certainly be

necesury

to

purchase

extended cables and brake pipes. Fortunately.

many

standard

motorcy

-

cles

have a custom version which

will

be equipped

with

higher

handlebars and . therefore. factory-

built

extended components

will

be

available from your local dealer.

It

Is

not

usually necessary

to

extend

electrical

wiring

, as switch clusters may be used on several different

motorcycles. some being custom

versions. This point should be borne

in

mind however

when

fitting extremely high

or

wide handlebars.

When fitting different

types

of

handlebar. ensure that the

mounting

clamps are correctly tightened

to

the manufacturer

's

speci -

fications and

that

cables and

wiring

.

111

previously mentioned. have

smooth easy runs and

do

not

snag

on

any part

of

the

motorcycle

throughout the full steering lock. Ensure that the fluid level

In

the

front

brake master cylinder remains level

to

avoid any chance

of

air

entering

the

hy

draulic system. Also check

that

the

cabl111

are adjusted correctly

and that all handlebar controls operate correctly and can

be

easily

reached when riding.

Electrical equipment

The vast range

of

electrical equipment available

to

motorcyclists

is

so large and so diverse that

only the

most

general outline

can

be

given

here. Electrical accessories very from electric ignition

kits

fitted

to

replace contact breaker points.

to

additional lighting

at

the

front

and

rear. more

powerful horns. various instruments and gauges. clocks.

anti-theft systems. heated clothing.

CB

radios, radio-cassette players.

and intercom systems.

to

name

but a few

of

the more

popular

items

of

equipment.

As

will

be evident. it

would

require a separate manual

to

cover

this

subject alone and

this

section is therefore restricted

to

outlining a few

basic rules which m·Jst be borne

in

mind

when

fitting

electrical

equipment. The first consideration is

whether

your

machine's electrical

system has enough reserve capacity

to

cope

with

the

added

demand

of

the accessories you wish

to

fit

. The motorcycle·s manufacturer

or

importer should be able

to

furnish

this

sort

of

information

and

may

also

be

able

to

offer advice on uprating

the

electrical system. Failing this.

a good dealer

or

the accessory manufacturer may be able

to

help.

In

some cases. more powerful generator components

may

be

available.

perhaps from another

motorcycle

in

the

manufacturer's range. The

second consideration is the

legal requirements

in

force

in

your area.

The

local police may be prepared

to

help

with

this

point

. In the

UK

for

example. there are strict regulations governing the position and use

of

auxiliary riding lamps and

fog

lamps.

When

fitting

electrical equipment always disconnect

the

battery

first

to

prevent the risk

of

a short-circuit, and

be

careful

to

ensure

that

all connections are properly made and

that

they are

waterproof

.

Remember

that

many

electrical accessories are designed primarily

for

use in cars and

that

they cannot easily withstand the ellposure

to

vibration and

to

the

weather. Delicate components

must

be rubber-

mounted

to

insulate them from vibration, and sealed carefully

to

prevent the entry

of

rainwater and dirt. Be careful

to

follow

exactly the

accessory manufacturer's instructions

in

conjunction

with

the

wiring

diagram

at

the

back

of

this manual.

Accessories - general

Accessories

fitted

to

your motorcycle

will

rapidly deteriorate

if

not

cared

for

. Regular washing and polishing

will

maintain

the

finish and

will

provide an

opportunity

to

check

that

all mounting

bolts

and nuts

are securely fastened. Any signs

of

chafing

or

wear

should

be

watched

for. and the cause cured as soon as possible before serious damage
occurs.

As a general rule.

do

not

expect the re-sale value

of

your

motorcycle

to

increase

by

an amount proportional

to

the amount

of

money and effort

put

into

fitting

accessories.

It

is

usually the case

that

an

absolutely standard motorcycle

will

sell more easily

at a better

price

than one

t~at

has been modified.

If

you are

in

the habit

of

exchanging

your

~ach1.ne

for

another

at

frequent intervals. this

factor

should

be

borne

'"

mind

to

avoid loss

of

money.

Fault diagnosis

In

t 1

oduet

lon

Engine does

not

start

when

tumed

over

No

hJel

flow

to

c&rt>u

et10f

Fuel

not

ra.ching

cy11~r

_

··-------

Eng

ine

flooding

-----~-------

No

spa!1( at

plug

------····-

W

eak

5011'\

at plug. -····--

·-··-·--------

Compression

low

.......

·····-···---

·--·

_____

--·--

Engine stalls afrer starting

2

3

•

5
6

7

General causes ....

..

.. . ..........

.

. ...

-····--

·---···--···-·-·····

8

Poor

running

at

idle

and

low

speed

Weak

spark

at

plug

or

errat

ic

flri

ng

.... .

....

-··········-····················. 9

Fue air m

hc

ture

incorrect ........

........

.................................... -............ 1 O

Compr

ession

low

........

..................................................................... ....... 1 1

Acceleration

poor

General causes ................................................ ..... ....................

.......

........ 12

Poor

running

or

lack

of

power

at

high

speeds

Weak

spark

at

plug

or

erratic

firing ..........

........................................

...

13

FueVair

mixture

incorrect ...............................

...

.....................................

14

Compre.ssion

low

...... ...

.. . ..

... .... . .

.. ... ... .................

....

.. ..

.. ..

.. ........

...

.........

...

. 1 5

Knocking

or

pinking

General causes .................. ......

....................... ........

...

..........

...

...

.............

..

1 6

Overheating

F

iri

ng

incorrect ............................................................... · ·

··

·· ....

····

··

..

·· ·

.. ····

FueVair mixture incorrect ...................................................................... .

lubrication

inadequate ..........................................................................

..

Miscellaneous causes ............................................................................. .

1

Introduction

17

18
19

20

This Section provides an easy reference-guide

to

the more

common ailments

tliat

are likely

to

afflict

your

machine. Obviously, the

opportunities are almost limitless for

faults

to

occur

as a result

of

obscure failures. and

to

try

and cover all eventualities

would

require a

book. Indeed. a number have been

written

on

the

subject.

Successful fault diagnosis

is

not

a mysterious 'black art"

but

the

application

of a little

knowledge combined

with

a systematic and

logical approach

to

the problem . Approach any fault diagnosis

by

first

accurately identifying

the

symptom and then checking through

the

list

of

possibile causes, starting

with

the simplest

or

most

obvious and

progressing in stages

to

the

most complex. Take nothing

for

granted,

but

above all apply liberal quantities

of

common sense.

The main symptom

of

a fault

is

given in the

text

as a majo

r

heading below which are listed, as Sections headings,

the

various

systems or areas which may contain the fault. Details

of

each possible

cause for a fault and the remedial action

to

be taken are given, in brief,
in the paragraphs below each Section heading . Further information
should be sought in the relevant Chapter.

Engine does

not

start when turned over

2

No

fuel

flow

to

carburettor

• Fuel tank

empty

or level too

low

. Check

that

the tap Is turned

to

·

on·

or

'Reserve' position

as

required.

If

In doubt. remove the fuel feed

Abnormal

engine noise

Knocking

01

pinli.lng ................................................................................

21

Piston slap

01

rattling

from

cylinder ..................................................

..

22

Other noises ..... . ...........

..

....

.......

...................

....

....

..............

................... 23

Abnormal

transmission noise

Transmission noise ..........................................

........................................ 24

Exhaust smokes excessively

Wh

it blue smoke (caused by

oil

burningl ...

....

.................

...

..............

25

Black

smo

ke

(caused

by

over-rich mixture) .................................... .

..

26

P?or . han<!ling ,

o_r

road holding

Directional instab1hty ...............................................................................

27

Steering bins to le

ft

or

right

......

...................

.........................................

28

Handlebar vibrates or oscillates ............................................................

29

Poor fro

nt

fork performance ..................................... .............................

30

Front

fork judder when braking

...

....................................

....

.................

31

Poor rear suspension performance

....................................................... 32

Abnormal

frame

and

suspension noise

Fr

ont

end noise

...

............

...

......................................................................

33

Rear suspension noise .............................................. .............................. 34

Brake problems

Brakes are spongy

or

ineffective ........................................

....

........

......

35

Brake drag ...........

...

...................................................................................

36

Brake lever or pedal pulsates

in

operation ........

....

.............................

37

Drum brake noise ............................................

......................................... 38

Brake induced fork judder .................................................................

.....

39

Electrical problems

Circuit failure .....................................................................................

........

40

Bulbs

blowing

repeatedly .......................................................................

41

pipe

at

the carburettor end and check

that

fuel runs from pipe

when

the tap

is

turned on.

e Tank filler cap

vent

obstructed. This can prevent fuel from

flowing

into

the carbur

ettor

float

bowl

bcause air

cannot

enter the fuel

tank

to

replace it. The problem

is

more likely

to

appear when the

machine is

being ridden. Check

by

listening close

to

the

filler

cap and

releasing

it.

A hissing noise indicates

that

a blockage

is

present. Remove th.e

~a

p

and clear the

vent

hole

with

wire

or

by

using an air line from

the

insid

e

of

the

cap

. .

•

Fu

el tap

or

filter

blocked. Blockage may be

due

to acc

umulation

°1

rust

or

paint flakes

from

the tank's inner surface

or

of

foreign

matte

r

from

contaminated

fuel. Remove

the

tap and clean

it

and

the

filter.

look

also

for

water

droplets

in

the fuel. .

1

• Fuel line blocked. Blockage

of

the

fuel line is more

likely_

to

resu

1

from a kink

in

the

line rather than the accumulation

of

debris.

3

Fuel

not

reaching

cylinder

feuh

diagnosis

16

fuel tank

by~pas

smg

the

filter

system

or

to

gumming

up

as de

bed

in paragraph 1. Water droplets in the fuel

al~

ieu aod

pa

ssages. The carburettor should

be

d1sman

ed

f

Of

cl

an.ng

e Fuel level t

oo

low

. The fuel level

tn

the float cham

bet' is

COfl

rol'

ed

by

float height. The fuel level

may

i

nereau

with

wea1

or

dam

ege but

w

ill

never reduce. thus a l

ow

fue

l level i1 an inherent

rath r th

an

develop

in

g condition. Checll

the

flo

at

hei

ght. renewing

the float

or

needle if required.

e Oil b

locuge

in

fue

l system

or carb

ure

llor (pe

tro

il

lub11cated

engines

only

).

May ari

se when

the

machine has been

par\ed

for long

periods

and

the

re&iduel

petr

ol

has

evaporated To rectrfy, dlsmantle

and clean the carbure

ll

or and tap. flush the

tanlo:

and fill

with

fresh

petroil

mh1ed

in the

correct proportions. Th is probl

em

can be avoi

ded

by

running the float

bowl

dry

before the machine is stored for l

ong

periods. Do not

attempt

to

use fuel which has bec

ome

sta

le

4 Engine

nooding

e Float valve needle worn

or

stuck

open

A piece

of

rust

or other

debris can prevent

co

rrect seating of th e needle against the valve seat

thereby

permitting

an uncont

rolled flow

of

fuel Similarly, a worn

needle or needle seal

will

prevent

valve closure . Dismantle the

carburettor

flo

at

bowl

for

cleaning and.

if

necessary, renewal

of

the

wo

rn

components.

I Fuel level

too hig

h. The fuel level is c

ontroll

ed

by

the float hei

ght

which

may

increase due to wear of the float needle. pivot pin or

oper

at

ing tang. Check the float he ight, and

malo:e

any necessary

ad

justments. A leaking

float

will cau

se

an increase in fuel level. and

thus should be renewed.

e

Blo

cked air

filter

. A badly r

estric

ted air filter w

ill

cause floodi ng

Che

ck the filter and clean or renew as required A collapsed inlet hose

will have a si

milar effect.

5

No

spark

at

plug

• Engine

stop switch off.

• Spark plug di

rty, oi

led or 'whiskered'. Because the

induct

ion

mixture

of a two-stroke

engine

is inclined to be

of

a rather

oily

nature

it

is

comparatively easy

to foul the

plug

electrodes. especially where

there have been repeated

att

empts

to

start

the engin

e.

A machine

used

for short journeys

will

be

more

prone to foul ing because the

engine may never reach full

operating temper

ature. and the deposits

will not burn

off

. On rare occasions a change

of

plug grade may be

required

but

the

advice

of a dealer

should be so

ught befo

re making

such

a change. 'Whiskering ' is a

comparatively

rare occurrence

on

modern machines

but

may

be

encountered

wher

e pre-mixed

petro

l

and

oil (petroil) lubrication is

employed. An

electr

ode deposit in the

form

of

a barely visible

filament

across

the

plug

electrodes can sh

ort

circuit the plug and prevent

its

sparking. On all

two-stroke

machines

it

is a sound precaution

to

carry a

new

spare spark

plug

for

substitution

in

the event

of

fouling

problems

.

• Spark plug failure. Clean

the

spark

plug

thoroughly

and reset

the

electrode gap. Refer

to

the

spark

plug

section and

the

colour condition

guide in Chapter 3.

If

the

spark

plug

shorts

internally

or

has sustained

visible damage

to

the

electrodes.

core

or

ceramic

insulator

it

should

be

renewed. On rare occasions a

plug

that

appears

to

spark vigorously

will fail

to

do

so

when

refitted

to

the

engine

and subjected

to

the

compression pressure in

the

cylinder

.

• Spark plug cap

or

high

tension

(HT) lead

faulty

. Check

condition

and security. Replace

if

deterioration

is

evident. Most

spark plugs

have

an

internal resistor designed

to

inhibit

electrical interference

with

radio

and

television sets.

On

rare occasions

the

resi

stor

may

break

down

.

thus preventing sparking.

If

this

is

suspected,

fit a new

cap as a

precaution.

• Spark plug cap loose. Check

that

the

spark

plug

cap

fits

securely

over the

plug

and,

where

fitted, the

screwed

terminal

on

the

plug

end

is

secure.

• Shorting due

to

moisture. Certain

parts

of

the

ignition

system are

susceptible

to

shorting

when

the

machine

is

ridden

or

parked

in

wet

weather. Check particularly

the

area

from

the

spark

plug

cap back

to

the ignition coil. A

water

dispersant spray

may

be

used

to

dry

out

waterlogged

components

. Recurrence

of

the

problem can be

Prevented

by

using an

ignition

sealant spray

after

drying

out

and

cleaning.

•

St

OP

s rch

shorlod. Mav

be

caused by w

ater

corrosion

or w

~,'

ater dispersant

and

con

racr clean i

ng

sprnys moy be

used

If thl fa; s

to

overcom the

probl

em

dlsmantling ond visual fnspocrlo

1'

of

I 10

sv r

ch

s

wi

ll

be

required

e

Sh

orting

or

open circ

uit

in wiring. Fail

ure

In o

ny

wire con n ctl

ng

any

of

rh

Ignition components w

ill

cause I

gnition m111fu11ct

i<>

n Chock

also that a

ll connectio

ns are clean.

drv

11nd tight.

e

Ign

iti

on coil

failure. Chec

lt the

coll

, reforring to Chop tor 3.

e

Caoacitor (condenser) failure. Tho capa

cito

r may bo chocked

mo

t

eas

ily by

substi

tution with

a repla

ceme

nt Item

. Blackonod conta

ct

brooller

points indi

cate capacitor mal

function but this

moy not olw

oys

occur

e Contact breaker

points

pitted. burned

or clo

sed up. Ch

eck tho

co

nta

ct breaker poi

nts

. referri

ng

to

Chapter

3. Check also that tho

low

tension leads ot the cont

act breaker

are

secure

and

not

shorting out.

8

Weak

spark

et

plug

e Feeble spark

ing

at the

plug

may

be

caused

by

~ny

of the

fa~lt

s

ment

ioned in the pre ce

ding

Section

other

than

those it

ems

in

tho

first

three paragraphs. C

heck

first

the

contact

breaker

assembly

and tho

spark pl

ug

. these

being the

most likely

culpr

its.

7

Compression

low

e Spark

plug

loose. This

will

be

self-evident

on

inspection.

and

may

bo accompanied

by

a hissing noise

when

the

eng

ine

is

turned

over

.

Remove rho plug

and

check

that

the

threads

in

the

cylinder

head

are

not damaged. Check also

that

the

plug

sealing

washer

is

in

good

c

ondi

tion.

• Cylinder head

joint

leaking.

This

condition

is oft

en

accompanied

by a high

pit

ched squeak from

around

the

cylinder

head

and

oil

loss

.

and

may

be caused

by

insufficiently

tightened

cylinder

head

fasteners

,

a

wa

rped cylinder head

or

mechanical

damage

to

the

head

surface

.

Re

-tor

queing

the

fasteners

to

the

correct

specification

may

seal

the

leak

in

some instances

but

if

damage

has

occurred this

course

of

action

will provide, at

best,

only a temporary

cure

.

• L

ow

crankcase c

ompression. This

can

be

caused

by

worn

main

bearings and seals and

will

upset

the

incoming

fuel/air

mixture

. A

good

seal in these areas

is

essenti

al

on

any

two-stroke

engine

.

• Pisto n rings st

ic

king

or

broken. Sticking

of

the

piston

rings

may

be

caused

by

seizure

due

to

lack

of

lubrication

or

overheating

as a result

of poo

r carburati

on

or incorrect

fuel

type. Gumming

of

the

rings

may

result from

lack

of use.

or carbon

deposits

in

the

ring

grooves. Broken

rings res

ult

from

over

-revving,

over-heating

or

general

wear

. In eith

er

case a

top

-end overhaul

will

be

required

.

Engine

stalls

after

starting

8

General

causes

•

Ignition

malfunction

. See

Section

9.

Weak

spark

at plug

.

• Carburettor

incorrectly

adjusted. Maladjustment

of

the

idle

speed

may

cause

the

engine

to

stop

immediately

after

starting. See

Chapter

2.

• Fuel

contamination

. Check

for filter

blockage

by

debris

or

water

which

reduces.

but

does

not

completely

stop, fuel

flow, or

blockage

of

the

slow

speed ci

rcuit

in

the

carburettor

by

the

same

agents.

If

water

is present

it

can

often

be

seen as

droplets

in

the

bottom

of

the

float

bow

l. Clean

the

filter

and,

where

water

is

in

evi

dence, drain and flush

the fuel tank

and

float

bowl.

• I

ntake

air

leak. Check

for

security

of

the

carburettor mounting.

Check also

that

the

carburettor

top

is

secure

.

• Air

filter

blocked

or

omitted

. A

blocked

filter

will

cause

an

over

-

rich

mixture; the

omission

of a filter

will

cause an excessively w eak

mi

xture.

Both

conditions

will

have a detrimental

effect

on

car

buration

.

Clean

or

r~new

the

filter

as necessary.

• Fuel fil l

er

cap

air

vent

blocked. Usually

caused

by

dirt

or

water

.

Clean

the

vent

orifice

.

~

Choked

exhaust

system

. Caused

by

excessive

carbon

build-up

in

t e system.

particularly· around

the

silencer

baffles.

In

many

cases

~hfese

c~n

be

detached

for

cleaning. Refer

to

Chapter 2 for

further

m ormat1on.

,

.

16

•

~

.e

caroo-i ..... ...,...,

..,

fa

~''?

w

6eca-bon<se

e-

"Vne

en

::eU<

..

e

oi

anw

"1l

ion

On

pr

he

eni;

~

-

from

"

.ed

erv1J or

~h

systems

Cieck It oil

T..ed

\he

re(Om

~

fl

~

Poor running

.r

idle

•nd

low

IPHd

• Soar\ ol

ug

tou

~

a

ty

or

incon

ec adjusted.

5" SKtioo

•

or

t e-

io

0-~

e-r

3

•

SOM\

olug

cap

or

"'¢

tension l!d ahorting.

Otedt

the

condition

ol

both

hese 1 erru

~

!\at

they

i re In

llQIXl

cond

lion

ind

dry

<>Cl

11

the U P II 11\ed

OOfTKUy

• *

olu

g

type

incorr

ect

F-

1t

olu

g of

correct

type

a

nd

he1t

range

H g

en

'"

Specif t

ions

In

certain

cood

tion

s a

olu

g

of hotter

0t

colde

r

type

may

be

requit

ed for nor-ma!

running

•

Con

act

bru

81

pomts

oo

ed burned

or

closed-iJp Check

the

coniac

bf-aa

er

a"4tmbty referr'ng

to

C apter 3.

•

lgn

tJOn •

ming

inconect

Che the

ignitJOO

timing

statically and

dynamic

al e

nsuT1

ng

tha he advance is f

unctioning

corre

ctly

.

•

Faulty

ignition

COil

Partial failure

of

the

coil

internal insulation will

d m1

n1$h

t • performance of the cotl.

No

repair is

O<>Mib

le. 1 n

ew

compon

ent

must

be

fitted

• Faul

ty

capacitor (con

denser)

A. fail

ure

of

the capacitor w

ill

cause

bl.a

eni

ng

of the

contact

bfea

lr.

er ooint faces and will all

ow excessive

spa

•

no

at

the poi

nt

A faul

ty

capacitor may best be checked

by

su

bstitut

ion of a sennc

e11b

le repl acement item.

• Def

ect

ive flywheel gene

rator

Igniti

on source. Refer

to

Chapter 3

or

further

det

ails

on

test procedures.

10

Fuel/air

mixture

inco"ect

• Intake a

ir

leak. Chec

k carburettor

mount

ings and air cleaner

for

security. Ensure

that

carbur

ettor

top

is ti

ght

.

• Air d

ea

ner clogged or omitted . Clean

or

fit air cleaner element as

n

ec

essary.

•

F-u

el level

too

high

or too low

. Check the float height. renewing float

or needle

if

required. See Secti

on 3 or

4.

• Fuel tank air vent obstructed. Obstruct ions usually caused

by dirt

or

water. Clean vent orifice.

11

Compression

low

• S

ee Section

7.

Acceleration poor

12

Genenil

causes

• All items as

for

previous Section.

• Choked

ai~

filter. Failure

to

keep the air

filter

element

clean ·

11

allow the build-up

of

di

rt

with

proportional loss

of

performance w;n

~

xt~m

e

cases

of

neglect acceleration

will

suffer. ·

holced_

exhaust system. This can result

from

failure

to

r

~n':

rv':~~~ti~:

~~~~'!':i

fr~:kthe

r silencer

b~ffles

at

the

pre:c~:~

noticeably sluggish. Refer

to

Ch~p~u;e

f

w1lfl

make_

the

machine

d

eca

rbonisation.

er

or

urther

information

on

• Excessive carbon build-

up

in

the en ine Th"

to

decarbonise the engine at the

spe

iflg d . . is can result

from

failure

o

il

consumption. On pump-fed

~

ie

interval

or

through excessive

.

engines check

pum

d"

pre-mix (petroil) systems check

that

.1 . . . P a 1ustment.

On

ratio.

01

•s

mixed

in

the recommended

• .

~gnition

timing incorrect. Check the

w1th1n

the prescribed range ens

"h

contact breaker gap and

set

If

unng t at

the

• ·t· • .

the contact

br

eaker assembl . .

•gm

•on

t1m1ng

is

correct

h Y

•s

worn

1t

may

• ·

t e gap and timing settings

to

coin

"d

P~ove

•mP<>Ssible

to

get

• Ignition

timing incorre

ct

Check

~ ~·

n~~essnating

renewal.

Chapter 3. Where no p;ovision

tfoe

ignd1~1on

timing

as descri

bed

in

, . . . . . r a

IUSfmPnt

e v :

.........

•

Meehl

• I

resistance

.

Checil

thlt

the br1kes

are

nor

binding

On

StM

!l macn·

ne.s

n particol

tr

note

that

the Increased rolli

ng resistance

ca

used

by

under-infl

1ted

tyres

may Impede

acceler1tlon

.

Poor running

°'

leek

of

pow.,

et

high spetlds

13

WNk

spertt

at

plug

°'

err•tic

firing

•

411

i

tems

11

for

S.ctlon

9.

• HT lead insulati

on fail

ure.

Insulation

failure

of

the

HT

lead

and

spark

plu

g t

ip

due

to

old

age

or

dam1ge

can cause

shorting

when

the

engi

ne

Is dri

ven

h1rd

. Thi1

condition

may

be

less

noticeable. or

not

no

ticeable

II

all

et

lower

engine

apeed1.

14

Fuet/air

ml111Ure

lnco"ect

e All i

tems

as

for

Section

10.

with

the

exception

of

items

relative

e

J11cl

usively

to

low

speed

running

.

e

Ma

in

jet

blocked

. Debris

from

contaminated

fuel, or

from

the fuel

tank. and

water

in

the

fuel

can

block

the

main

jet. Clean

the

fuel filter,

the

float

bowl

area. and

if

water

is

present, flush

and

refill

the

fuel

tank.

e

Main

jet

is

the

wrong

size.

The

standard

carburettor

Jetting is for

sea level

atmospheric

pressure.

For

high

altitudes,

usually

above

5000

ft. a smaller

main

jet

will

be

required.

e A.ir bleed holes bl

ocked. Dismantle

carburettor

and

use

compressed

air

to

blow

out

all

air

passages

.

•

Reduced fuel

flow

. A

reduction

in

the

maximum

fuel

flow

from the

fuel tank

to

the

carburettor

will

cause

fuel

starvation, proport

ionate to

the engine

speed. Check

for

blockages

through

debris

or

a kinked fuel

line.

15

Compression

low

• See

Section

7.

Knocking

or

pinking

16

General

causes

• C

arbon

build-up

in

combustion

chamber. After

high

mileages

have

been covered

large accumulations

of

carbon

may

occur.

This may

glow

red

hot

and

c

~use

premature ignition

of

the

fueVair

mixture

, in

advanc

e

of

n~rma

l

firing

by

the

spark

plug. Cylinder

head

removal will

be

required

to

allow

inspection

and

cleaning

e F 1 · .

in

ue

inco~rect

_.

A

low

grade

fuel, or

one

of

poor

quality

may result

c

o~p~ession

induced

detonation

of

the

fuel

resulting

in

knocki

ng

and

pinking

noises

. Old

fuel

can

cause

similar

problems

A too

highly

leaded

fuel

will

red d . . · .

f

. .

uce

etonat1on

but

will

accelerate

deposi

t

ormat1on

in

the

comb

t" h

. . .

us

ion c amber

and

may

lead

to

early

pre

·

1gmt1

on

as

described

in

item

1

•s

.

i~k

plug

heat

range

incorrect.

Uncontrolled

pre-igniti

on

can

~s:;.J

~m

~he

use

of

a

spa~

plug

the

heat

range

of

which

is

too

hot.

ea

m_•xture. Overheating

of

the

engine

due

to

a weak mixture

can

result

in

p _. · • .

.

re

ignition

occurring

where

it

would

not

occur w

hen

~e~in~

temperature

wa~

within

normal

limits.

Maladjustment. blocked

1

0

passages

and

air

leaks

can

cause

this

condition

.

Overheating

17

Firing

inco"ect

ee~s~pa:rk:;:--:p:lu~g~f:o~u~led"":""'"~d-f::---.~~~~~~~~~~--=----

•

Spark

plu

: e

ective

or

maladjusted.

See

Section 5.

that

the

corrgectyt

pel

incorre~

.

Refer

to

the

Specifications

and

e

n~

0 11n tvn a.

•n

i:--~

hult

d

•onoeJ•

18

Fu•

air m l(ture

l

ncorr~

e M

in

j

el wron

g

lll

l

Qll o

ph rlc

con

<J111on

1 F 0 1

ama

ll

r rnotn I I

111

uu

• Ah ftllOI

b1d

lv r.11 d 01 om111

t

hll

II

1\

1 I II\

place

nd

fltt

•d

ur ly

e Induct

on

olr I Ch cl\

th

u

rit

of

ti

carbur

ll

Ot

m~ntl

t11,1

Chock al

so

th 1 th c1rbu1 1101

toP

11

uro

e

Fu

I I vol t

oo

low

S

e Fuol tnnk

11

11

r c

op

nh d

CIMr blot

l..

g

19

Lubr

lcetlo

n l

nadequete

e P

1101/

oll

111

xtu10 lncorro t.

Th11

pr

ponlon

of o

il

m

1

,od

with th

petrol

In

tho

111nk

Is c

riti

1tl

11

th

e ttngine Is

to

oerform

co11ectly

T

00

httlc

oil will

lo11vo

tho re i

pro

ati

ng

p1tr11

end

beiuings

pooily

lubricated

and

ovorh 11tlng

will

o vr .

In

ei.11em c11se

th engm w

ill

seize

. Co nv rsoly, t

oo much

oil will

elfe

t vely

d•

plec

11

similar

amount of

petrol.

Though thl doe1

not often cnu

so

over

hoatmg

In

p111

ctlco

1t

Is po Sibl e

thnt

tho res

ultant wo11

1\ ml1<turo

may

c11u

0

overheotlng. It

will

lno

vitobly

cou o

11

los

ot Power

1100

1

, c

0

si

vo

oKhnust

smok

•

e Tronsmission

oil

low

or

worn out Chock th lcvol , gulorly

onc

t

investigate ony loss

of

oil. II tho oil lovol dr

op

with

no s1yn

ol

•to

rnol

leakage It Is likely

that tho c

ronksholt

rnoln boorlno

oil

Orll oro w orn,

allowing tronsrnission

oil

to

bo d1ow

n 1

1110 th

o crn

nlo.cMu

dwinu

induction.

20

Miscellaneous

causes

e

Eng

ine

fins clogg

ed. A

build

uµ of

mun

in lho

yli

ndor h

on<!

111111

cylinder barrel

cooling

fins

will

docroaso lho cooling copr1bi

lit

ios ot tho

fins. Clean

the

fins

as required.

Abnormal

engine

noise

21

Knocking

or

pinking

•

See

Section 1 6.

22

Piston

slap

or

rattling

from

cylinder

• Cylinder bore/piston clearance excessive. Resulting fr

om wea

r.

or

partial seizure. This

condi

tion

can

often

be

heard as a

high

, rapid

tappi

ng

noise when

the

engine

is

under

little

or

no

load. particularly

when

power

is

just

beginning

to

be applied. Reboring to the next

correct oversize should

be

carried

out

and a

new

oversize piston

fitt

ed.

• Connecting rod

bent

. This

can

be caused

by

over

-revving. trying to

start a very badly flooded

engine

(resulting in a hydraulic lock in the

cy

linder)

or

by

earlier mechanical failure.

Attempts

at straightening a

bent connecting rod

from a high

performance engine are

not

rec-

ommended. Careful

inspection

of

the

crankshaft should be mode

before renewing

the

damaged

connecting rod.

• Gudgeon pin, piston

bo

ss bore

or

small-end

beari

ng

wear

or

seizure. Excess clearance

or

partial seizure

between

normal

moving

parts

of

these items

can

cause

continuous

or

intermittent

tapping

noises. Rapid wear

or

seizure

Is

caused by lubrica

tion

starvation.

• Piston rings

worn

, broken

or

sticking. Renew

the

rings after

ca

reful inspection

of

the piston and bore.

23

Other

noises

• Big-end bearing wear. A pronounced knock

from

within

the

crankcase

which

worsens

rapidly

is

ind

icative

of

big-end beorlng

failure

as

a result

of

extreme normal wear or

lubrication failure.

Remedial ac

ti

on In

the

form

of a bottom

end

overhaul shou

ld

be token;

continuing

to

run the engine

will

lead

to

further damage Including the

Possibility

of

connecting rod breakage.

•

•

ll

nd111

111111

11

lolnl

le11ld11g

. Thi! 110

1!1

0 111011 O

fh

Jn

ll1t8

111

lnt11<I with

• I

long head

lo

nt la

11 high

pit

h111I

8{f11Mklnu.

11ltl1011u11

1111y

1

1th111

n~I

tent w

lh

g u rntlng for

11d

out

11ndor

J)lll

li8l

rrll

1111111

n

t1

1111tll

c

1111

111

o

mi

eml1111d. L1111k1111t1

11 of111n

11c

omp1111l11d

hv

{}II

e Pll{I from

11roum1

th11 m11

tlng jol

n1

Of

I

mm

11111

yllnrlor 1

11'

rul

h

kl1n{1

flo

w11

bolts 1

md

n11t1. li'111k11011 101

111

11 horn ln11

11rn

111

111

11r

unhen

hg

hten

ng

of the ayllnrt

er

h1u1tl

fn11011or

8,

or

tr

om

rnnctn111

m ch

n1c11I

falluro Retlghtilnlno

to

thn

cor

rillll

tn1(J110

llouro will

, f

it

best

only

prov1cle

tt1mpor11ry cur11

.

• e

,11

11s

t syst

11m

l11nk11gt1

Popping

or

or

11C

kllnu In thn oxhtltllll

"V"lflln

pnrtl

11torty

when

II o

ao

urs

with thi!

"''(lino

on

lho

OviHrnn,

inc

ll

c 1

11

pcor

joint

ellh11r

at 1he ayllru

lor

pnn

or 111

thn

11-h1111111

pl

J}

llonc r

co

nno

ctlon. Fallurt1 of

tht1

011

sknt

or

· l

on11onoH

ol

tho

lornp

~hou

ld

ho lookocl tor.

Abnormal

tranam/Hlon

noise

24

Tren1ml11lon

nolH

• Soaring

01

bushos

worn

or

domnyed. R11now

lhn

&ffec

tod compo

·

no11t

s

• Goor pinions

worn

or chipped

. Ronow

tho

ooor

pinions

.

• Motal c

hips jnmmod

In

00111

teeth

.This 0

110

occur whon

plo

coo of

rn

otol lrom onv lnllod c

ompono111

aro plc

kod

up

by o rno1hln11

pinion.

Tho condition

will

lood 10 ropld boorl

no

woor

or

early

oeor

lnlluro

.

•

Eng

ino/tronsmisslon

oil

lovel

too

low .

Top

up

lmmocJl111o

ly

to

provont dornogo lo goorbox ond

onolnc

.

• Chain snagging on coses

or

cyclo

parts

. A

bodly worn choln

or

OM

that is oxcossivoly looso m

oy

11nog

or smock ogolnst odlncon l

co

mp

ononl s.

Exhaust

smokes

excessively

25

White/blue

smoke

(caused

by

oil

burning)

• Piston rings

worn

or

broken. Breakago

or

weer

of

eny ring,

but

particularly

tho

oil control ring,

will

allow

engine oil pest tho piston Into

the combustion chamber. Examine

and

renew,

where

necessary,

tho

cylind

er

barrel and piston.

• Cylinder cracked,

worn

or

scored. These conditions

may

be cousod

by

overheating, lack

of

lubrication.

component

failure

or

edvancod

normal

wear

. The cylinder barrel should be renewed and,

If nec11111nry,

a

new

piston

fitted

.

• PetroVoil ratio incorrect. Ensure

that

oil

11

mixed

with

the

potrol

In

the correct

ratio

. The

manufacturer

's recommendation must bo

adhered

to

if

excessive smoking

or

under

-lubrication is to

bo

avoided.

• Crankshaft main bearing

oll

seals

worn. Wear

In

the

main

booring

oil

seals.

often

In

conjunction

with

weer

In

the

beorings thomsolvo11.

can

allow

transmission

oil

to

find

Its

way

Into

the

crankcoso ond

thence

to

the

combustion

chamber. This condition Is

often

lndlc111od

by

a mysterious

drop

In the transmission oil lovel

with

no

sign

of

ox1ornol

leakage.

• Accumu

lat

ed

oll

deposits

In oxhaust system.

II

the machlno Is

usod for short journeys

only

It Is possible for

the

oll

roslduo In tho

exhaust gases to condense In

the

relatively cool sllencor.

If

tho

machine is then taken

for

a longer run In

hot

woathor

. the ac

cumulot

od

oil

will burn

off

producing

ominous

smoke

from

tho exhaust.

26

Black

smoke

(ceused

by

over-rich

mixture)

•

Air

filter

olemont

clogged. Clean

or

renow the olomont.

18

Poor

h•ndlmg

o'

ro•dholding

27

• ring

1\

0 11 t>-a

ung

•<lN•l

m

oo

1'(1t11

T 1 w1

\f

H rolling

Of

""

.,..

no

11

~<w:I•

Re 1tJ

1u

11

1h<ll

~·

•

no•

• l"""llO

11d l)"•

nno

w ain

oi

d1m1g.cl

Com1

1

.a

1

u11mt n1 of

t b

lntlQ

w'tll l)<OVI lmPO&t;b49 to •

9'1•

11

WHr

01 d m

•Qe

..

occurr

od

lnc:on 1

!!Ml h11no1tno

will

OGc.ur lnci

udUlQ 1 •tlQ

0r

w

•1v1n

(I

111

k>w

r.oeed

11\d

poor dir11

c11on11

wntrol 111 l

0t1e

tl!lrrn1n11111 1(1

"'

w I

ft

t

II

ring h

11d

~

1111ng

ihould

b•

d 1m1ntf

lf(l

l

0t

n

~

1101'

11

!"1

r n"'1v

11

r9flu11e0 w

hr1c.1111

on

1hou

ld

el"'

h•

urrlt<

I ou1

• 6

111r1ng

ril

e. I p1

1111d

or den1

Cl

Impa

ct

d11m1ge c.11u111d

r>•rh11i:

,.

by

an

1oc1d nl or r c

lln(I

over

11 pol h

ole c•n c1uM ln<Jenuitlon

ol

the

t>o

111ng

uw

lly

In

ono

poahlon

1 h

i•

1hou

ld

b• note

d u

no1<.hlMu

w n

th

hllndl

b11r1 ar11 lurnod ReMw

and lul

}rlUl

l!i

1116

btt1tr1nu1

•

S1

ring 1t11m

bon1 1 h

la will

oc.cur

only

II

1h11

m11 hln11

la

5Ub1

tod

to a hi

gh lmpa1.t 1uch

111

hltllng

11 c.u

rb

or a 001 hol'i I h!J

low

r vok

111om 11h

ould be

runewo

cl.

do

not

1111ernot

10 a1111

lght11n

1he

11111m

• Fron

t 01

re111

lyre me11

ur11

1 t

oo

low

• F

ron

t or

roar

tyre

w o

rn Generlll

ln11!lbollly, hi

gh 11n•J•

HI wOl)IJlts!I

and

s opp1ng

ovo

r w hole

llno

a l

ncJ

1ca111s

thnt

tyru rono

wol

may

t11s

requ1

rod

Ty

r

Induced

problem

a,

In

11o

me mo

chlnts/tyr11 c

omlllr1111

r)rlff

,

can

occ

ur

even

when tho

tyro

In ciuo

1oon

11

hy

no

mean

~

f

ully

worn

•

Swinging

orm

beorong

11

worn

Dllfocul

ll!l

ll

In ho

ld1n11

tin•:.

p1r1o

cul

arly

when cornering

or

when

ch1

rnglng pow111

B

11trlno~

1

ncJ

lco

tris

w ear

on lhe 1w1ng1ng

orm

boorlngs The 11

wongong

arrn 11hould ho

r

emoved from

tho moc

h1no ond tho b11arlng

11 ren

•sw•Jd

•

Swinging

arm flexing.

Tho

B

ympt om~

glv1

1n

In

the

pr1Jc;•idl

no

p

arag

rap

h w

ill

also occ

ur

ii

tho swingi

ng

arm fork

llox1J6

hMlly

Thill

can

be caused

by stru

ctural

weakne

ss

as a res

ult

of corr

o'11on.

foti(ju•

i

01

impact

damage. or

because

the

rear

whe

el 11p111dle

Is sla

ck

•

Wheel

bearings

worn

. R

enew

the

worn

bearings

•

Loose wheel spokes. The

spokes s

hould

ho rlght!ln'ld

r:v!lnly

ro

mainta

in

tension

and

trueness

of

the

rim

.

e

Ty

res

unsuitable

for

machine

. No t

all

ava

ila

ble

tyrns will suit

tho

c

haracteristics of

the

frame

and

suspension

. i

ndeed

. eom c

tyro

s or

tyre

combinati

ons

may

cause

a

transformation

in 1hc

handlino

ch

aracter

istics. If

handling

problems

occu

r immediately

alter chanoing

to a new

tyre

type

or

make. revert

to

the

original

tyre

s

to

see

wheth

or

an

improvement can be

noted. In

some

instances

a c

hange

to

what

are, in fact, s

uitable

tyres

may

give rise

to

handling

defi

cio

nces.

In this

case a

thorough check

shou

ld

be

made

of

all

frame and su11pension

items whic

h affect

stability

.

28

s

...

ring

bi••

to

left

or

right

• Rear

wheel

out

of

alignment. Caused

by

uneven

adjustmenl

of

chain

ten1ioner adju

ste

r•

allowing

the

wheel

to

b9

111kew

In

the

fork

end

s. A

bent

rear

wheel

1plndle will

alao

misalign

the

wheel

in the

sw i

nging

arm

.

•

Whe

els o

ut

of a.lignment. Thia

can

be caused

by

l

mpa

c1

damage

to

the

fram

e. 1wlng1

ng

arm. wheel aplndlet

or

front

forks. Although

o

ccas

ionally a result

of

mat

erial

failure

or

corro1lon

It

11

usually

111

a

res

ult

of a craeh.

29

Handlebar

vlbretH

or

oscllletH

•

Tyro

11

badly

positioned

on

the

wheel

rims

. A

moulded

line

on each

....

f •

1,1•

,, l

lf'""'"'

' I

••

1t

ll··~

, •

,,_,

.,.,

,10

1

••

·•1/1 I'•' fl"' ,

,,

,,

t.Qf

••

llt

1

;r

I

'

~

I

1.-

1 II " • lfll

Ii

•I

*'

' I

111

1 •

ll1~1f.,

'' I

ll1111f

,, ',I r.

~

ltt9

t

ir

11.>t

tJ'

I

1tl

""

1 l

,11

l

lllll•'l

'll'l

fll

( f1l / l '111•

e

y.,1

, ' 1110 ,,,.,.,,,,..,

11~

1

l"l

lf11'1J'••I

l!1*f•••

I ti - fJlr

•1•~

1

1

,1

l•H.•

rrf

t

tf

•• ' .

..

,, .,. ,

ft "'"'

,,

.

.,

• 1.., ,,, ,,,

rm

ll

t1r10•

w

111t1

I """"' fl,., 11-.•rff •

e

WI""

' J• ,

,.,

1 11

•1111 I 1111

11 a 11"

111

•

e

11

...

rlr

r,

•I

'••ll

liltfl•

""

•111.;

r

Il

l

111l

jr1

•l'lt

l / 1

l,fl•ll•1f1 ''

rr '"•

..

...

. r' ,

,,

, .

..

,

11

1r1,111

,,

....

tr

• ,

,,

,,•It

.,,, ,,,,,

,.,,,

....

l•ll

l•ll ' ' "' "

fh'

, ,

..

, •

fl

ot

•lj•

rtl

II

e 11

01

f1 •

• lJJll'ffiO

f

(1I

~

Ult1lf1IJI

..

111 I

U!t!fl'll

il ' ' " ' ' " r11

1l

ll 1111•1 t,•,

IJ6

lt11l1f.

1:.

11111

ln

10 leg•

wh

1i11

f •pl

ntJI

tr111tf1Jllll

•ll• l

tl

•llfnt

ill

lJ

<il111fl

1,

1tl

1 f1f• 111

'

"~

al 1 01fli) Ii i 11•4 11 r 1Jlel1

111i.

I

ht'i

l11i,_ "'' 1

111111INiJ

(J'llfl

•Ill.Ii

Illa ll

tll l•,t

,

4

ltvl •

1lf}4lfll)f)O

l lllJHl•I

1111

f,1111•,~

ll(Jhl'll•"'

'

l•

t;/,1t

\lt11f11

JI

/

l'J

J1f'l I r,

ti•

1111

..

,.

fll<)l!!r "''

IJ

I 1

mr

1fl1""'''"

''"

m1l11a

• r nylnot ffli1HOlllllJ lif1lll

IOO"I

l l

tjhl'i

tl

11

11

l

811l

•IJl'!•4

•

Wf!li~ h'JI~

prlf!Oil

l'rt~t

f!•lil

18

l11fl(l

o14

11

1

tll'I

1 1

11~

11µ1

fl!J'

rilii

ulrtng

In

11 ''" " " "'' •

flr

lrlU ''""

l"J

llCJ!h, w 11

1fl

•A.tll111

11111

11f1J

llllf/IJ

11"°

T

h"'

"1

11f

111

1i1

11 "''"

01u1r1r

,"'

"'~"'"

'""

1or~

'''"" 1

m1

1.,,

1i,,.~'""

·

11w1

,,

'" 1

1th.11111

t

.,,

1 IQ

rm

il'1

lll

111•lur.11 fllli

Iii

r111tf

"ll'lnd'i

(I

l1111c,11

h

r,

f

11111

l•,1~

r

11rw1 r

h11•

1h•1

fur~

u.,•,

mtsr1

1

A111l!1w11I

r

1I

r

h11•11t1ny

11u111

111

lr

lei

lh

•1

"'

''~

11111.,lllf triry

l,lJ•ll~

'l

f1f

111,1111!1

• ll<1

nt 1

111

nr)olr1111

or

f.l)trfltflfrl

"t11111,l

1l1111

11

!foth 1,1,1;<lll

lum1 w lJ

IJ"

111'""

c;tlt

t'l

t;r

t'll•1<1'.

•1t

1lny

ol

rh" lmt-l'i(lli,

llflll 111

1111 lid .11J111..41(l

•llilt

1;

1111

1.1111ftfl .,1

11.

i..1110

f)

f 1ti" fur

"'

In

m1., 1

1011 tlon

111

Ii

ml

l<l

lurm

1.om11W1,1

w lll "

""

"'' Mlc.tl11n

'''

thli

101~

lh'ir!Jt

l!/

lnt.-r

'lli

llln

q 1

h11 tlr

n11 ti>'

•uftP••n-l

un

ro ~•

J~

1•

1

tt111

r.1

rn

1111

11rltfll'in

11111rl

11urfll(,'I. 011

rrt

f

ur~

•

1rt

nr,hlo

rn1

11huultl

t.1i 1111•rnr

llfd

IO

ltn

mli

tllli

V;ly

11fl

(,1'Uli'I

lh~y IMlii,1~

tho! IHl

pfH

. I

rl

flmf1~1·

1

tir1

11

l)f,1,

111r;;11

,

llrtrl

th•1r11

111

8

d11nq1;r

lhlft

lh#

fo~1

will fall with

rllri.111

111111

11

1,1111!1's(lo1'1rlt,'i

!i

31

Frmit

fl)rk

Judder

when

br•klng

IH•

•It<>

8!tet1on

341

• W••·" l1•1rw•; •

1n

'"'

'

frn~

r..

ronr.hl

•,11

11

11111

1 tht1 l

mk

ffJQ\.

R,;n11,.111

t

rA

th•1 rrll•i•.l•sll 1,

umprm1sr11r1 111

r1Jqulrt11l

,

•

lt1r.~

M•1rirl

no lt•1rirl b<srsrlnu

11

flt, a

cJju11t th!i

1li;11r1ng11

,

•

Wri

rp•irl

tmi~o

rll1.r.

or

drurn.

II lrr•squl111 braking 11

ctl

on

occu

r•

for'•

1wl<l•11 r.rs11 h•: 1nd11c.•;

ll

111

what

rtr•i

nor

mally

116rv1Gll

11IJl

!.i

lor

tu. R

!ir11;1

,

thr: •l'1rM11j•1d

tir:i

k1i 1,1Jffl(J

1Jn

•sll

llj

,

32

Poor

rear 1uapenalon

performan

ces

•

W11r

1~

rfj;_ir •ipr1ng11.

If

thr, -iuF.pcn11lon

unit apring

11

fatly

u!J

lhliV will

nrnmmr,

1

:1t.IJ'l'iiv1,

1111r.hlnu

of 1hc mach

ine

and

ror.Juefi

thi; g1ouoo

cl

r,1Jnsn1

,•1 whr

:n corn1srl

rou

.

• S

w1n111

no

arrn

fl

r,~ln

11

or b•s

arino

w orn. S

•:!.i Scct

lon1

27

and

213

Abnormal

frame

and

suspsn•lon

noise

33

Front

end

noise

•

Sp

rino

weak or broken. Makc

11

a clic

king

or acraping

111>1

1rid

• St•:

cri

ng

head bea

ring

s 1

0086

or

damaged. Clickl

when

bfakitlg

Che

ck.

adju11t or

ropl

ace.

•

Fork stanchi

on

bent. Go

od p

o111l

bility

If machine hH

b!;e

n

dropped

. R

epair

or

repla

ce

tub

e.

34

RHr

1u1pen1ion

nolH

•

Deloctiva

rear

1u1pen11ion

unit

with

Internal damag

e. Renew t

he

au11ponalon

units

a1

a

pair

.

Brake

p'obl•m•

3&

Brakes

ere

spongy

or

Ineffective -drum

brekff

•

Brake cable

detor1oratlon.

Dam11ge

to

the ou111r cat

ile

111

F

eult dlegnoalt

19

stretchi

ng

or

being tra

pped will

g· e a

soongy

le I to

tile

br

a

The

cable shou

ld

be re

newed

. A cabfe

wh

leh has be

com

e corroo d ue

to

old

age

or

neglect

of lubrication

wi

U partia

ft

y s I

ce

ma

ng

operation

very

heavy. Lubricati

on

al

this

stage

may over

com

e the probt

em

but

the

fitting

of a

new

cable Is recomme

nded.

e Worn brake

linings

Dete

rmi

ne

tinin

g we

ar

u ng the

e11tem11l

brake wear

indicator

on

the

btake

backplate

or

b rem

ovi

ng

the

wheel

and

withdraw

ing

the

brak

e bac plate R"n

ew

the ahoellini

ng

units

11

a pair

if

the

lining

s are w

orn

bel

ow

the reco

mmended limit

e

Worn

brake

camsh11f1.

Wea1 between the camsha

ft

and

the
bearing surface will reduce brak.e feel and reduce operating efficiency
Renewal

of

one

or

both items will

be r

equired

to rect i

fy the fau

lt.

e

Worn

brake

cam

and

shoe ends R

enew the w

orn

comoonen

ts.

e Lini

ngs contaminated

with

dust

or

grea e.

Any

accYmulatlons

of

dust should be cleaned fr

om the bralle assembly and

drum using a

petrol dampened

cloth. Do

not

blow

or

brush

off

the

dust

because It

is asbestos based and

thu

s ha1mful if inhaled Ligh t contamination

from grease can

be

remove d from the surface

of

the brake

lin

ings

using a solvent;

att

emp

ts

at remov

ing

heavi

er con

taminati

on

are

leu

likely

to

be

successful because some of

the

lubricant w i

ll

have been

absorbed

by

the

lining

mat

erial

which will

severely reduce

the

braki

ng

performance.

36

Br•k•

dreg -drum

brakes

e Incorrect adjus

tment

. Re-adfust

the

brake operating mechanism.

e Drum

warped

or

ova

l. This can result f

rom overheating

or

impact

or uneven tension

of the

wheel

spokes. The condit

ion

is difficult to

correct. although

if

slight

ovali

ty

only occurs. skimmi

ng the surface of

the brake

drum

can provide

a cure. Thi s is

work

for a specialist

engineer. Renewal

of

the c

omplete wheel

hub

i~

normally the

only

sat

isf

actory

solution

.

e Weak brake shoe re

turn

springs. Thi s

will

prevent the brake

linin

g/

shoe

units

from

pulling

away from the

drum

surface once the

brake is released. The

springs

should be renewed.

e Brake

camshaft

, lever

pivot

or

cab

le

poorly

lub

ricated. Failure to

attend

to

regular

lubr

ication

of

these areas

will inc

rease ope rating

resistance

which. wh

en com

pounded. may

cause tardy operation and

poor release

movement

.

37

Brake

lever

or

pedal

pulsates

in

operation

• Drums

warped

or

oval. This can result

from

overheating

or

impac

t

or uneven spoke tensi

on

. This

condition

is

difficult

to correct. although

if

slight ovality only

occurs

skimming

the

surface of the

drum

can

provide a cure. This

is

work

for

a specialist engineer. Renewal of the

hub is normally

the

only

satisfactory sol

uti

on.

31

Orum

bt•k•

nolae

• Or\lm warped

01

ovel. Thia c1n c

au111 Intermitte

nt rubbing

of

th

e

brali.e llnlng1

1g111n11

the

drum

.

See

th

o precedi

ng

Section.

• Brak e llnlng1 gl

1tod

Th

l1 co

ndition,

usu11llv 11

cco

mpan

led

by

heavy lini

ng

dull

cont11mlnat

lon, often

ln<lucH brake

squul.

The

surface of the llnlng1

m•v

be

roughened usi

ng

glau

-paper or a

One

me

31

lr•k•

Induced

fork

judder

• Wom fro

nt

fork 1

t11n

chlon1 and legs,

or

worn

or

badly

adjusted

steering head bearing1. These condi

tions

, c

omb

ined

with

uneven

or

pulsating braking

11

deacribed In Section

37 will

Ind

uce

more

or

leaa

judder

when

the

br11k11

are applied. dependent on the degree

of

wear

and

poor

brake

ope

ration.

Attention

1hould

be given

to

both

areas

of

ma

lfunction. See the relevant Sectlona.

E/11etrlc•I

problems

40

Circuit

f•llure

• Cable failure. Refer

to the machine'•

wiring

diagram

and

check

the

circ

uit for

contin

uity

. Open circuits are a

result

of

loose

or

corroded

connections. either at

terminals

or in-line connectors,

or

because

of

broken

wires. Occasio nally, the core

of a wire

will

break

without there

being any apparent damage

to

the

outer

plast

ic

cover

.

•

Switc

h failure. All sw

itches may

be

checked

for

continuity

in each

s

wit

ch posi

tion. after

referring

to

the

switch

position

boxes

incorporated in the w

ir

ing

diagram

for

the

machine. Switch

failure

may

be a result

of

mechanical breakage, corrosi

on

or

water

.

41

Bulba

blowing

repeatedly

• Vibrati

on

failure. This is

often

an

inherent

fault

related

to

the

natural

vib

ration characteristics

of

the

engine

and

frame

and

is,

thus

,

diff

icult to resolve .

Modifications

of

the

lamp

mounting, to

change the

damp

ing characteristics. may

help

.

• In

term

itt

ent

earth. Repeated failure

of

one

bulb, particular

ly

where

the

bulb

is fed

directly

from

the

generator, indicates

that a poor

earth

exists somewhere in the circuit. Check

that a good

contact

is available

at eac h earthing

point

in the circuit.

Check

list

l

....,_l...,~

.........

.

._........-

...

.._

,.

__

l...,.

•.

.,

,~

.......

l.,Vft

... ,

,...,

......

.,.

~

, ........... .,.,....,

..

.....

....

tNlf'I

4 , ....., ,

...,.

... ~ ...

~.,..,..

c

...

,.

,..,...

,_..,

"'-'.

·~

w-..

_.

,,,..,

'

.._.,...

......

...

J (

.....

~

r'Wt

•• , .....

f'IA

,._

• 1>tC e

"1

'

c

Not

.

•N'I

r1 " '""'

....

. . ,

(

Not

•

•<wt

._'1

.,

,.._

.........

II/

..,

..

.,,.....

~

..

the

...

'"' • ""

l

wt;

W

•tri

ft~

I

tlif\t't

• I

•IMil

\ut"'1(attt"""

1

,,,..1

, ,

tu~-t

C-

111.,..

.,,

1

ft

tM

th4t

•"

f1IH

11

Ott<•~_,,.._.~

..

CNw

lt

th•I 1tW

mt'

•

hll\tl

l

•tttngl

a

""1

lultt

n*ll •'"

h(lt\I

0.... •

IN

,,_,

,. , I l>rt"•lt.11t

Q"P

a

nd

topl~~t.ort l1t'1•~

()wi.<:• r'W1

~·~"'4

,.,,.

IWl~·no

••

rn

H.H

tnbt\'

0.,,.-,"""

I

•""°

.c.i

l'U

• I thfll tlH

f"'Q h11ta

;1 hee11ng•

It

~

°'""

..

mev1

ttw

-.

h.t>

i"la

--035-045mm

Adjustment

data

_,.

__

-_.l

., i.G

g

t.

-

()

QJO""'

2'

1110-t<>on

OO

! r

1

1·oc

'

!'0""!'!

11C*

tt

...

l ' •

C

h.ckmv

tha

tper

k

pl

ug

gap

Recommended

lubricants

Compon~

t

Ouentit'

r,

pelvi•

co1

lty

0 Gu

,bo

•

200

ct

10

Jb

po

n1l

Tvpe A A

lf

or SAE

IOW

IJO molar

oU

0 ,

""''

di

-v

• t

hl

lf'I

A

.J

rtt(luU"'

Aaro'-0' ch1

1n lut>ncent

(D

rrori

1

'°'

'

h.ibe~

AJ •

•au!rtd

Gennr1I

purpoH

oreate

0 \.\-'hftl

be1

nng

1

At teQ

v••MI

U'Qh

mtll

ll'

'O

J>Ot'll greue

<D

St"""V

h.,.

d

AJ

lttQUlted

Ge

ner

t l

purpe>se

grease

be•"''9•

@ s"'

""'tio0

•"''

AJ

1.au

ued

Gentr•I

purpoH

grnH

~"''''tV

·

(!)

H•r~tl

eb•

t

lttver

As

1euuued

M

OIC

)f 011

or

W04

0

()1¥01•

@ S

ttt

ndDt'IO

IS

A

.!

1ec1u11ed

Mo lor Otl

Of

W04

0

©

Cc>f'

t10I C

f't

>I• •

At roc1ul10'1

G1rne1al

pu1

pc>se 011

Gearbo•

011

filler, level

and

drem

plug locetiqns

Filler plug

Level screw

Oram

plug

RDUTINI

MAINTINANCE

GUIDI

j

Routine

maintenance

Periodic routine maintenance is a continuous process which

should commence

immediately

the machine is used. The object is to

maintain all adjustments and

to

diagnose and

rectify

minor

defects

before

they

develop

into

more

extensive. and

oflen

more expensive.

problems.

It

follows

that

if

the

machine is maintained properly,

it

will

both

run and perform

with

optimum

efficiency.

and

be less prone to

unexpected breakdowns. Regular inspection

of

the

machine

will

show

up any parts

which

are wearing. and

with a little

experience.

it

is

possible to obtain

the

maximum

life

from

any

one component,

renewing

it

when

it

becomes

so

worn

that

it

is liable to fail.

Regular cleaning can be considered as

important

as

mechanical

maintenance. This

will

ensure

that

all

the

cycle parts are inspected

regularly and are kept free

from

accumulations

of

road

dirt

and grime.

Cleaning is especially

important

during

the

winter

months

. despite

its appearance

of

being a thankless task

which

very soon seems

pointless. On the contrary,

it

is during these

months

that the

paintwork,

chromium

plating, and

the

alloy casings suffer the ravages

of abrasive

grit

. rain and road salt. A couple

of

hours spent

weekly

on

cleaning the machine

will

maintain its appearance and value, and

highlight small points. like chipped paint, before

they

become a serious

problem.

The various maintenance tasks are descr

ib

ed under

the

ir respec­tive mileage and calendar headings. and are accompanied by diagrams
and

photographs where pertinent.

It should be noted

that

the

intervals

between

each maintenance

task serve only

as

a guide.

As

the

machine

gets

older. or

if

it is used

under particularly arduous conditions,

it

is advisable

to

reduce the

period

between

each check.

For ease

of

reference

most

service operations are described

in

detail under

the

relevant

heading. However, if

further

~eneral

inf_or-

mation is required,

this

can be found under

the

pertinent Section

heading and Chapter

in

the

main

text. . •

Although

no

special tools are required

for

rout1~e

mamtena~ce

,

a

good selection

of

general

workshop

tools

is

esse~t1al:

Included

in

the

tools

must

be a range

of

metric

ring

or

combination

spanners, a

selection

of

crosshead screwdrivers, and

two

pairs

of

circlip pliers, one

external opening and the

other

internal opening.

Additiona

lly.

owing

to

the extreme tightness

of

most

casing screws on Japanese machines,

an

impact screwdriver, together

with

a choice

of

large

or

small cross-

head screw bits, is absolutely indispensable. This

is

particularly so

if

the engine has

not

been dismantled since leaving the factory.

_,,..--'

Cleaning

the

machine

Keeping

the

motor

cycle clean should be considered as an

important part

of the routine maintenance,

to

be

carried

out

whenever

the need arises. A machine cleaned regularly

will

not

only

succumb

l

~!iS

speedily

to

the

inevitable corrosion

of

external surfaces. and hence

maintain

its mark

et value,

but

will

be far more approachable when the

time comes

for

maintenance

or

service

work

. Furthermore. loo

se

or

failing components are more readily spotted

when

not

partially

obscured

by

a mantle

of

road grime and oil.

Surface

dirt

should be removed using a sponge and warm, soapy

water

; the

latter

being applied copiously

to

remove the particles of

grit

which

might

otherwise

cause damage

to

the

paintwork

and polished

surfaces.

Oil and grease

is

removed

most

easily

by

the

application

of

a

cleaning solvent such as 'Gunk'

or

'Jizer

".

The solvent should be

applied when

the

parts are still

dry

and worked

in

with

a sti

ff

brush.

Large

quantities

of

water

should be used when rinsing

off

, taking care

that

water

does

not

enter

the carburettors.

air

cleaners or electrics.

If

desired a polish such

as

Solvol Autosol can be applied

to

the

aluminium alloy parts to restore

the

original lustre. This does not apply

in

instances.

much

favoured

by

Japanese manufacturers. where the

components are lacquered. Application

of

a wax polish

to

the cycle

parts and a

good

chrome cleaner

to

the

chrome parts

will

also give a

good finish .

Always

wipe

the machine

down

if

used in the w et. and

~ake

sure the chain is

well

oiled. There is less chance

of

water

getting

m~o

control cables

if

they

are regularly lubricated .

which

will

prevent

stiffness

of

action

.

Rout1nemall1181181IC9

n.

cheddisC

lhowr1

below

should

be

carried

out

poor

to

rid

ng

the

m8Chine

NCh

day

The

procedure

should

take

only

a

few

moments

end

wiU

reduce

the

risk

at

~ed

fa

re

fn

use

(aJ

Check

brake operauon

bJ

Check throttle operation eng e

stopped

(cl Chee\

tyre

pressures and ch for

damage

d Check the e ectrlcal

1JY51em

(el

Check

f11

fevel

ThrM

monthly,

or

every

1000

miles

1

lubricating

the

control

lever

points

The handlebar lever

plvot

should be lubricated

us

ng

motor

oil

from an o I can or one

of

the g nerel-purposc aerosol

ma

ntenance

sprays

such

es

WO

40

Ch

c that the lever

pivots

are secure

and

unworn.

and

that

the

control operate

moothly

2

lubricating

the

stand

pivots

Lubncat tho stand pivots using engine

oil

or

a general purpose

melntenanc aerosol such as

WO

40

Ensure that the stand operates

smoothly

and

retracts fully Check the condition

of

the return spring

r newing

11

if

11

11

weakened

or

damaged

3

lubricating

and

adjusting the final drive chain

Place the machine on

its

centre stand so

that

the rear wheel

is

raised clear

of

the ground. Using

an

old rag.

wipe

off

any accumulated

road

dirt

from

the chain Lubricate tho chain, using one

of

the

proprietary chain lubricant aerosol sprays. ensuring that the whole

chain is coated and taking care

10 avoid getting lubricant on the rear

wheel or tyre.

Check

the

amount

of up·and

down

play in

the

chain. Make the
check several times, turning the rear wheel between checks Chains
rarely

wear

evenly in service , and the significant reading is where the

chain is at

its

tightest point.

If

correctly adjusted, the chain should have a

total

of

20

mm

(f in)

up and

down

movement.

If

adjustment is required. slacken the rear

wheel spindle nuts and move each

of

the snail cam adjusters by an

equal amount,

to

preserve wheel alignment. Tighten the wheel spindle

nuts and recheck the adjustment.

IO

mm

T /

~

l

10

mm

Final

drive

chain free

play

measurement

Lubricate

the

chain using an aerosol

lubricant

4 Checking

the

spark

plug

Remove

the

plug

cap

and

unscrew

the spark

plug. Check t

condition

of

tho

plug

electrodes.

compari

ng

it

with

the

colour

sectl

in Chupter

3.

Where

necessary, clean or

renew

the

plug.

For furth

information, refer

to

Chapter 3 Section

6.

5 Cleaning

the

exhaust

baff

le

Remove

the

single

screw

which

retai

ns

the

exhaust

baffle

in

end

of

the

silencer. Withdraw

the

baffle

and

remove

any

ca

deposits, using a

wire

brush

If

the

baffle

proves

difficult

to

remove,

the carbon

build

up

seems

heavy,

refer

to

Chapter

2,

Section

8.

R

emo

ve the

single

screw

at

the

end

of

th

·1

e

s1

encer

...

6

Checking

the

gearbox

oil

level

Place

the

machine 0 't

level

screw

from

the

.

~1 ~stand

on a level

surface.

Re

gearbox

oil

is

up

to

ther;g

tj

and

engine

casing

and

chtCk

the

right-hand

engin

ev~

of

the

threads.

Where

nece

automatic

transmissio~

~

~~ud(

and

unscrew

the

tiller

required.

ui

ATF)

or

SAE

10W

30

• then pull

out

the baffle

for

cleaning

Oil

should be level

with

plug threads

Top up using funnel.

or

gear oil squeeze pack

•

7 Ch«lcing

the

eltlctricel

system

Pl•ce

the

m11chlne

on

Its

stand.

atwt

the

engine

end

dow

•

ID

idle

Outck

the

oper•tlon

of

the

lights. breke

light

awltchee

end

ham.

eod elso the

tum

slgnels where fitted Replece

any

blown

bu._

end

rectify anv

other

feult. referring to Chepter 8 for further

lnformedan

8 Checl<ing

snd

adjusting the brakes

The setting

of

the brake ceble edju1ters

will

very according

to

personal requirements ,

but

as e general guide

the

brakas ahould

start

to

operate almost

as

soon

as

the lever begins

to

move, but

without

causing drag

when

released

If

there

11

Insufficient travel aveilable et

the adjuster, screw

it

fully home, then reposition the

lower

end

of

the

inner cable in

its

cleat at the operating lever. Make any fine

adjustments using the threaded adjuster.

Slacken locknut (arrowed) then reset the adjuster

Slacken retaining

nut

(arrowed)

to

reposition cable inner in

the

cleat

9 Checking

and

adjusting the idle speed

The engine idle speed should be checked

with

the

machine

on

lta

stand and the rear wheel clear

of

the ground and free

to

rotate. The

engine should be

at

normal runn ing temperature, so make

the

check

immediately after a run.

Start

the

engine and

allow

it

to

Idle. Using

the

adjuatlng screw et

th~

han~lebar

end

of

the cable, set

the

Idle

speed

at

the

llowell

~ehable

t1ckover. The rear wheel may

tum

during

the

ed)ustrnent,

It

should be possible

to

stop

it

easily

If

the

rear brake

Is

applied. M

Routlne

.........

•11:e

....

tD

....

the

engine

the

Ille

speed

19

...

too

high

and

the 1

S1

......

dutch

wll

have 9taf'ted

IO

engege

IMPORTANT NOTE:

It

Is

wr.t

m.t

the

enfl""'

idle

~

Is

,,,.,,,alned

corrKt/r

.,

a#

ttmn.

If

the

Idle speed ls

set

too

high. the

MllOmatic clutch

may

come

mto

~11tton

when

the

machine ls

wpposed

to

be

at

a standst

'/,

• potentially dangerous

slru11t1on

If

clutch drag s

stfll

evi<Mnt

llfter

Idle

sf)ttd

adjustment. dismantle

and

check

the

dutches (see

Chapter

1

for

det1111&}

Six

monthly.

or

every

2000

mrlu

Carry out the operations descnbed under the three monthly

1000

m e head ng then complete the following

Changing the gearbox

oil

The gearbox oil should

be

changed

with

the eng ne

at

normal

operat

ng

temperature

to

ensure that

it

drains fully and eas ly, taking

with

t any contamln:ints. For this reason the

job

should be undertaken

1mmed1atcly after

tho

machine has been run

Remove

the

right hand engine shield

by

releasing the single

cheese head

screw

and the

two

cross head screws which secure

it

to

the frame Place o tray

or

bowl

of

at least

400

cc (1.0

Imp

pintl

capacity beneath the drain

plug

Remove the drain plug filler plug and

the oil level plug and

allow

the

oil

to

drain completely.

2

Gearbox

oil

filler.

level

and

drain

plug

locations

1

Filler

plug

3

Drain

plug

2

Level

screw

Gearbox drain

plug

is located on underside

of

the crankcase

Refit the

chin

plug. Ullng a

new

l88llng

...._If

tighten

it

securaty. Top

up

with

SAE

1C:JN/30

mo&arol

automatic transmission fluid

CA

TFJ

untU

the

oll

just

begJn9'

from

the

level hole. Refit and secure

the

level

end

fller

the right-hand engine shield.

2 Lubricating the control cables

Before adjusting the control cables. lubricate

them

using

or

a general purpose lubricating oil.

It

will

be

necessary

to

free

upper end

of

the cable

to

gain access

for

lubrication. In the case

of

brake cables. release the

lower

end

of

the

inner

cable

from

Its

cleat

the operating arm. The upper end can

now

be

pulled clear

of

the

I

stock and disengaged

Pull back the

twistgrip

rubber

to

expose

throttle

cable

cable suspended

•----

vertically

cablfl

lubriur.d

-

""".,,

oil

dripl

from

far

Md

Oiling a

control

cable

To

free thtl throttle

cmle.

wort

the

twiatgrip

rubber

pen

way

on

the (Wlatgrlp barrel

to

8xpoM

the

inner

cable

end

nipple

Pu the cable

outer

1111(1

diMngage h from

the

twistgrip

hou

ng then unhook the

1nner

Cheek

the exposed section

of

Inner cable carefu

ly

Any

broken

.irande are Indicative

of

Imminent

fa lure and

the

cable ahou d be

renewed

without

delay Remember

that

a broken atrand cou d easi

ly

jam the cable.

Support the cable

upright

by

taping

It

to

the handlebar Form a

small funnel using Plasticine

or

by

tap

ng o plastic bag orou

nd the

outer cable as ahown In

the

accompanying

lino

draw

ing

Add a

few

teaspoons

of

oil

and

allow

It

to

work

through

the cable

until

It

emerg s

at

the lower end

If

possible. leave tho machine overnight to ensure

that the oil

works

through.

A quicker method requ ires the use

of

o proprietorv cable oiler.

available from

most

motorcy

cle dealers. These deVtce cla

mp

around

the cable. Oil is then forced through

th

e cable by turning a screw.

Newer types use a smaller

fitting

. through wh

ich

a maintenance spray

such

as

WO

40

can be introduced

3 Lubricating the

front

fork

tubes

To minimise wea r pull

dow

n the fork dust seals and remove any

accumulated dirt. Apply

gr

ease to

the area

around the

bottom

of

the

upper tubes and re

fit

the dust seal.

4 Cleaning

and

oiling

the

air

filter

The air filter

must

be kept clean

if

it

is

to

function efficiently.

If

allowed

to

get

badly choked, fuel consumption

will

increase

<1nd

the

engine will run badly, due to t

he

excessively rich mixture.

Pull

off

the rubber adaptor hose

which

connects the carburettor

and

the intake silencer. Prise

out the

wire

mesh filter element from the

mouth of the carbure

ttor

.

Wash the e

lement thoroughly in clean petrol. repeating the

operation until all

dirt

and old oil has been removed A

llow

the element

to dry, then soak

it

in clean engine oil before refitting

it

Remove

air filter element, wash

in

petrol and re-oil

5 Decarbonising the engine . . . t

To maintain efficient running

of

the

engine

1t

1s

necessary

0

remove the build

up

of

carbon

from

the cylinder head. exhaust port and

O.en

off

the carbon

from

the

cyllnder held

Ullnl

•

to

~d

sc:ratchlng

the

elloy

turfece

Though not

1111111111.

Internal aurfece can

be

polished

to

reduce

the

rwte

at

which

builds

up

In

the

future, using a proprietary

metal

polleh

auah

• 8otilf

Autosol

Remove the left-hand engine casing end

tum

the generator ratOr

unti

l the piston Is about t In from the

top

of

the

bore Apply •

llMlf

of

grease

to

the

exposed bore surface

to

trap any

loote

cerbon

then

carefully clean

off

the piston crown . Gre1t care must

be

taken

to

avoid

d mago

to

the piston material or the bore surface.

Wipe

out

the resulting debris, than turn the rotor

to

lower

the

piston slightly (do

not

expose the piston ports)

Wipe out

the

gre1H

and trapped carbon

to

complete the operation.

Usi

ng

a screwdriver

or

a similar tool, clean

out

the exhaust port,

taking care not

to

damage the piston. Clean

out

the exhaust pipe

In

a

similar manner.

Reassemble the cylinder head and the exhaust system. Note

that

the cylinder head nuts should be tightened progressively,

in

a diagonal

sequence to 1.2 kgf m (8.7

lbf

ft).

6 Checking fittings

and

fasteners . . .

Give the whole machine a close visual examination, making sure

that all fast

en

ers are secure and undamaged. Apart from

the

obvious

purpose of

pr

eventing the unintentional departure

of

any

loose

component. the check affords the opportunity

to

make any necel'.5ary

running repairs

to

areas which

might

otherwise have gone

un~ot1ced.

It

is preferable to make this check immediately after the machine has

been cleaned.

Yearly.

or

every

4000

miles

Ca

rry out the operations described under

the

three

monthly/1000

mi

le

and the six monthly/

2000

mile headings, then complete the

following

1 Checking the

contact

breaker

points

and

ignition

timing

Ch

eck and where necessary reset

the

contact breaker gap as

described in Chapter 3, Section 2, then check

the

ignition

timing

as

de

sc

ribed in Section 4

of

Chapter 2.

2

Checking

and

overhauling

the

swinging

arm

assembly

The swinging arm bushes should be checked

for

free play and

renewed

or

lubricated as appropriate. The procedure is detailed

in

Chapter 4. Section 6.

3 Overhauling

and

adjusting the steering

head

bearings

Dismantle, check and lubricate the steering head bearings as
described in Chapter 4. Section 3. Reassemble the steering head.
ensuring

that

the head race adjuster

nut

is set correctly. See Chapter

4, Section 4

for

details.

4 Checking

and

overhauling the wheels

Check

the

wheels

for

trueness and damage as described In

Chapter 5, Section

2

or

3 as appropriate. Check the wheel bearings for

free play and renew as necessary. Remove the wheels and grease

the

wheel bearings. Refer

to

Chapter 5, Section

8.

Chapter 1

Engine and transmission

Content.

General dellCfipti

on

. ... ...•.

...

.. • ...

. .

------··

Operations with t

he

engi

ne

unit

in t

he frame

····-·-·-·-·--·

Open11

ion1 requ

iri

ng engine removal

UICI

of

soeclal 1

0011

.•••.....••..•

R

emoving the

eng

ine unlt f

rom

the

frame

D

asm11ntltng the

engine/

gearbo• unit . preliminaries

..

Dism&ntltng t

he

engine/

geerbo•

unit removin

g t

he

cylinder head

b11n

el

and

pis

ton

. . ................................... .

D

i5man

tli

ng the

engine/ge11

rbox uni

t. remov

ing

the flywheel

gen

ra

tor assembly

.. ..

........................... .......

..

D1sman

tltng t

he englne/

gearbo)( unit·

remov

ing

the transmission

co

mpo

nents ........................................................................................ .

D

ismantling

the

engine/gearbox unit : separati

ng

the crankcase

1

2

3

4

5
6

7

8

9

halves ...................... ................

....

....................................................

...

....... 1 O

E.umination 11

nd

renovation: general .................................................. 1 1

Cylinder head· uamlnation and renovation ....................................... 12

Cylinder barrel: examination and renovation ...................................... 13

Piston and rings

: exa

minat

ion and renovation ..................................

14

Cranks

haft

asse

mbly

: exa

minat

ion and renovation .......................... 15

Sm

all-e

nd

bus

h: examination· and renovation ................................... 16

Specifications

Engine

Typ

e .....................................

.......................................

............

....

...

...

.........

.. .

Bor

e ..........................

...

............................

...

..............

.................................

..

.

Stroke

............................................................................

.......

.................

......

.

Dis

placement

..........................................................

................................

...

.

Compression ratio ..........

....

....................................................................... .

Power

output

.........................................................................................

....

.

Cylinder head

Type .....................................................

...

.....................................................

.

Cylinder barrel

Type .......................................................................................

....

.................

. .

Standard diameter ...........

..

....................................................................... .

Piston

Type

·················································

·····

···

·······················

···

···············

·······

···

··

Diameter

....

...........................................................................

.......

.............

..

.

Crankshaft assembly

~~~

·b·~·~·

;1~~~

··:.·.·.·::

.·

.·:

.

·.·:.

·:::

:

.·.·.·

.

·::::.·

.

·:::.

·

:.·.·.·::.·.·::.·.·:::.·.·:.·.·.·.·::.·.-.·.

·

.·::

.-.

·

.·.·.·.·.·.

·

:.·.·.·

.

·:.·.·

.·.

·.·:.·.·.

·

.·:.·:.·.·.-.

~~~~ln:n~e~:~~~~

·:···

·

················

·

············

·

·············

·

········

·

··

··

···········

· ·

······

·

·····

6~~~~~

·

~;

·::::::::::::::

:

::::

:::::::

:

:::

:

:::::::::::::::::::··········

·

·············

·

········

·

········

·

·

Maximum

crankshaft runout: .................

....

...................... .

At

main

bearing journal ...................................

....

............................ .

At

mainshaft ends

·············································

·············

·············

···

···

·

Crankshaft end float

.................................................................................

.

Adjustment

method

......................

....

...... .

Shim

sizes available ······

············································

......

...

...

...............

...

......

...

.........................................

..

Main and gearbox bearings and

oll

seals: examinat

ion

and

re

novation ..

.......................................................

.......

.........

...

...................... 17

Crankca

se

castings: exemlnatlon

and

renovation .........................

....

18

Centrifugal c

lut

ch asse

mbly: dismantling

. overhaul

and

reesse

mbly

.......................

.......................................................................... 19

Tran

smissio

n gears and roll

er clut

ch:

dismantling. ove

rhaul and

reassembly

..

.................................

....

..........................................................

20

Klckstart mechanism: examinat

ion

and

renovati

on

........................

..

21

Engine reasse

mbly

: general ........

..................................................

.......

..

22

Engine reasse

mbly

: refi

tting

the

main

bearings

and

oil

seals

and checki

ng

crankshaft end

float

....................................................... 23

Engine reasse

mbly: joining

the

crankcase

hal

ves ....................

........

. 24

Engine reassembly: re

fitt

ing the transmission shafts and

centrifugal c

lut

ches ....................

...

...........................................................

25

Engine reasse

mbly

: r

efitti

ng the

flywh

eel

generator

asse

mbly

......

26

Engine reasse

mbly: refitting the

pis

ton. cylinder

barrel and

cylind er head ............................

..

............................................................... 27

Fill

ing

the engine

unit

into

the

frame

....

.............................................

28

Starti

ng

and running the

rebuilt

engine

..............................................

29

Single cylinder air-cooled

two-stroke

38

mm ( 1.

496

in)

43

mm

( 1.

692

in)

49

cc (3.0 cu in)

8.5:1

2

hp

~

5500

rpm

Light

alloy

Cast iron

38

.01 -38.

02

mm

(1.4964 -1.4968

in)

Light

alloy

Refer

to

text

Pressed-up

assembly, full flyw

heel

Journal ball

beari

ngs

Roller

Bronze

bush

10

.01 -10.

02

mm

(0.3941

- 0.

3945

in)

0.01

mm

(0.0004

in)

0.

02

mm

(0.0008

in)

0.

02 -0.12

mm

(0.

0008

- 0.

004

7

in)

shims

0.1, 0.

15

and

0.2

mm

(0.004

. 0 .

006

and

0.

008

in)

Chapter 1 Engine

end

tr•namlHlon

27

Prlm•rv

tr1n1ml11lon

Typo

Aot

o ·

111t

......

2nd
St

nr

tor oorir

Clutch ond float
Thrust wosh ra ov

II

bl

Shoo to drurn cl arnncn

secondary

tran1ml11ion

Typo

........

............................................

....

....................

Choln

si

ze .

·········

..............................

······························

Torque

wrench

aetting1

component•

..........

...

..........................

...

.......................

............................

...

.........

...

.................

...

..

Clutch rotalnlng

nut
Tronsrnl slon covor screw

Cylinder hood nut ......

Generotor rotor n

ut

.........................

.....

......................

...

...

Qener•I

de1criptlon

The

Tornos

mopod

s e

mpl

oy

o single cylinder air-

coo

led

two~stroke

engine built In

u

~it

with

th

outomotlc tw

o-speod transmission . The

engine

Is

of

tho piston ported

typ

o. u I

ng

a cast Iron cylinder barr

el

in

conjunction

with a light

olloy

cyli

nder

hood, tho folnt between the two

effected

by

ground soollng locos.

The crankshaft is o

pr

osso

rl

up

nsso

mbly aupportcd

on a fournal

ball

main booring at ooch o

nd

. A rollor

big

end is

fltt

od.

whilst

tho small

end bearing

Is

of the bron10 bush

typ

o.

A

two

-speed

primory

tronsrnlssion

system is

fitted

and

Is

controlled

by two centrlfugol clutches. Those operate sequentially 10

ensure that the machine

moves

otf s

moo

thly

as the

throttle

is opened.

As

the mac

hine gath

ers spood tho second, higher ratio. overrides 1st

gear

to

give better

economy. On

steep gradients

the

machine

will

revert

to

1st ge ar as the engine speed falls.

2

Operations

with

the

engine

unit

in

the

frame

The

items

listed

bel

ow

can

be remov

ed and overhauled

without

removing the engine un

it

from the

frame. It

should be

noted, however

,

that engine removal is a rela

tiv

ely easy task and should take about half

an

hour

or

less. In view

of

this

it

is recommended

that

where

a number

of operations are

to

be

undertaken. th

e engine should be removed

to

gain better access and

more

com

fortable working conditions

.

a)

Cylinder head. barrel and

piston

b)

Centrifugal c

lut

ches and transmission gears

c)

Kickstart mechanism

d)

Flywheel genera

tor

assembly

3

Operations

requiring

engine

removal

To gain access

to

the

following

components

It

will

be necessary

to

r~move

the engine

from

the

fram

e,

remove

the

flywheel generator.

k1ckstart

mechanism and

the

transmission

components

to

allow

the

crankcase halves

to

be separated.

a)

Crankshaft assembly

bl

Main

bearings

c) Transmission bearings

4 Uae

of

special

tools

In the course

of

the

workshop

project

on

which

this

manual Is

based

it

was established

that

it

is possible

to

strip and reassemble

most

of

the engine assembly

without

the

use

of

the

manufacturer's

service tools.

In

some instances a degree

of

Ingenuity

will

be required

to

hold

or

remove a

particular component

, and details

will

be

found

In

the relevant Sec

tion

.

Some

own

ers may

prefer

to

obtain

the

official

tools

, and these

c~n

be

ordered through

Tomos

dealers.

Whilst

the

tools are primarily

A

11tom1tlc

1....,

0 llOfl!ld

Oetl

r drlvo

tw

n Cflntr

lfug I ChJtch

I

4 3 3 I I 1 / x

74

TJ

2 4

02

t (20 JI 4

11

0 4

65

t {"

...

71 tJ

0 1 3 0

mm

10004 0012

lnJ

0 3 and 0 6

mm

1

0012

1nd O

020

lr1J

0 4

mm

(0

0167

lnl

approc

Ch1ln

i

11

4 In,

90

llnlla

kgf

m

2.5

t.O

1.2

J.O

lbf

ft

18

.0

7.2

8.7

21

.7

Intended for professional use. many can

be

used

to

advantage

at

homn.

6

Removing

the

engine

unit

from

the

frame

Pl

ace the machine securely

on

Its

centre

stand

leaving

adequate

working space on

both

sides. Place a

bowl

or

drain

tray

beneath

the

transmission drain plug.

which can

then

be

removed and

the

oil

allowed to drain. Note

that

the transmlSBion casing

holds

about

200

cc

11

Imp

pint). Leave the oil

to

drain

whilst

continuing

the

dismantling

sequence. remembering to refit

the

drain

plug

before

the

engine

is

lift

ed

out

of the frame

to

avoid

spilling

any residual oil.

2

Wh

ile the oil Is draining, remove

the

two

side

covers

. Each

is

retained

to

the frame

by

two

self-tapping

screws

on

the

upper

edge

and a single larg e cheese-headed

screw

at

the

side. Remove

the

single

bo

lt

whi

ch secures each footrest and

lift

them

away

.

J Slacken

the

nut

which

retains

the

kickstart

lever

cotter

pin. leaving

the nut flush

with

the

end

of

the

thread.

Using a soft

faced

mallet

or

a hardwood block and a

hammer, drive

the

cotter

pin

out.

Remove

the

nut and displace the

pin

to

free

the

kickstart

lever. Lift

away

the

spacer

followed

by

the

kicks

tart

return spring and

its

two

end

caps

.

4

Slacken and remove

the

three

screws

which

retain

the

engine

left-

hand cover, then

lift

it

away. Note

that

if

It

Is

intended

to

separate

the

crankcase halves

It

is advantageous

to

slacken

the

gearbox

sprocket

nut

at

this

stage. Straighten

the

locking

tab,

then hold

the

sprocket

by

applying the rear brake whi

lst

the

nut

is

slackened

by

one

or

two

turns

.

5 Turn

the

rear wheel

until

the

final

drive

chain

joining

link

is

a~cessible.

Using pliers, displace

end

remove

the

spring

clip,

disengage

the

ends

of

the

chain and

remove

it.

6

Slacken

the

two

screws

which

retain

the

cable channel

to

the

underside

of

the

tank. The

channel

has

keyhole-shaped

slots

and can

be

slid

to

one side and

lifted

clear.

7 Unscrew

the

knurled

carburettor

top

and

pull

out

the

throttle

valve

assembly.

It

can

be

left

attached

to

the

throttle

cable and lodged clear

of

the

engine.

8 Disconnect

the

leads

from

the

flywheel

generator

at

the

Lucar

connec

tors. Note

that

the

engine

earth

lead

will

remain attached

but

will

be freed

when

the

engine

mounting

bolts

are removed .

9

Unscrew

the

union

bolt

which

retains

the

fuel pipe

to

the

carburettor. Disengage

the

pipe and

refit

the

bolt

and sealing washers

for

safe keeping.

1

0 Remove

the

two

exhaust pipe

nuts

and

the

single silencer

mounting

nut

and

lift

away

the

exhaust system.

11

Slacken and remove

the

three

engine

mounting

bolt

nuts,

holding

the

bolt

heads

to

prevent

rotation.

Displace and remove all

but

the

centre bolt, ensuring

that

the

earth lead

terminal

is freed

from

the

front

bolt

.

12

The engine is

now

ready

to

be

lifted

away

from

the

frame. It

is

not

h~avy

and

will

be

easily managed

by

one

person.

Support

the

engine

wit~

one hand and

withdraw

the

remaining

bolt. Lower

the

engine

,

notrng

that

the

rubber

air

filter

hose

will

pull

clear

of

the

intake

~i~en~er

.

Pla~e

the

unit

on

the

workbench

to

await

further

dismantling

.

e rntake silencer

will

drop

as

the

unit

Is

removed

and

may

be

lifted

away

.

f teppmg screws

5

2b

and

by

a single cheese heeded scrow

at the side

5.6 Slacken retaining screws and disengage channel

5. 7

Un

screw carburettor

top

and

withdraw

the

throttle

valve

assembly

5.8 Disconnect the generator wiring at the Lucar connectors

,,,,,,--

-

Chapter

1

Engine

end

tr•nsmlalon

29

I

Ofernentllng

the

englne

/ g11tbo11

unit

·

~•llmlneri"

8

.,

10

11

,

11riy

(11smnntl ng

wo1k Is undet111ken. the

ex_tetn11

1 aurfRces

the!

unit ah

ould

bt1 thoroughly

clun11d

11nd

degt

11ted Th 1 will

of

11111

the co111nmlr111tlo11

of

the

onglnt lnt

em1111, 11nd will

111ao

meke

~=r•dng

8

lot

081101 8nd cl

Hne

1 A hi

gh flu h

p0l

nt

solvent. 1uch

111

81

"

11

1

11

(ke•o•on

el

cen be u

1ed

, 01

better

11111. e proprie

tary engine

P eosor

11uch

H Gunk.

U111

old

palntbtvehea 11nd too

thb1v1he1

to

:0:,~

tho solvent Into tlH1

v11rlou1

19ce1111 of the engine

c1t11ing1

. Teke

lo

.,.-elude

11otven

t or

water

Ir- om tho t1fectr

ic11I co

mpanent

1 end

co

re!

u

11

,11,1 nnd ox_h8ltlt pans. The VIM!

of

petrol

lg111ofl

ne)

111

e chutnl

ng

,nl!fli

urf1

shou

ld

be

1tvo

lded

, beceuee

the

v11pour

11 ex_ploslve

end cen

mi t

ox

ic

11

usnd In

11 conflnnd

1p11

ce.

2

- Whlln

cle11

n end

dry, 11rr11nge the

unit

on

the

workb

enc

h, leavi

ng

a

auitnble cl

o11r

11r11e

for working.

Gethor e 111

loc1ion of s

mell cont

11lners

snd

p11111t

ic

begs

110

that

Pllt1!!

can

be

grouped together In en eeslly

ldo

ntlfleble

mann

er.

Some

popor

end 8 po

n should

be oo

hend

10

permit notes to be

modo end

lnbol

s e

ttached where nec

ess11ry

. A

supply of cl

on

n regs is el

10 required.

3

9

11

fore commencing wor

k. r

end

through the

1tppropri111e

section

so

th

et some

idi!•

of

the nece1"ary procedure cnn

be

goinod. Whon

remo Ing

the

v11rlou.1

engine

c:o

moonents

It should

be

notud

th

It

groot

force 1 seldom reoulred,

unleu

specl

f14td. In

mt1ny coses. o

co

mp0nent

s r luc

tan

ce 10 be

romoved

Is indicative

of

on lncorroct

1ooro11

ch or r

ooiovat method. II

In

11ny

doubt

, re-check wi

th th

o IU•I.

7

Dl1m1ntling

the

engln1

/geerboJ1

unit: r•movlng

th•

cylinder

hHd.

ban•I

end

pleton

1 This operation can

be

cnrrlod

out

with

the eng

lno

unit

In or

out

of

th

e fr

nme. II

the engine

11

Insta

lled

In the frame It will first

bo

nec

euary

to

remove

the

e111h11u11

1y11em

by

releasi ng

the two

e111

hnus1

part

flenge

nuts

and the 1lngle silencer

mounting nut

. In

olthor

caso,

release

th

e cnrbure

ttor

by

removing

the

two

flange

bolts and

lilt

It

cloor

of

the

b11rrel

.

2 Slncken evenly and progre111lvely

the

four

cylinder

head

nuts

,

turning

eoch ono

by

about t

turn

until

pre11ure has

been

reloasod from

th

e head. Run the

nuts

off.

then

lift

the

cylinder

head

away

from

tho

holding

studs

.

3

Th

e head will no

rm11lly

come

away

quite

easily.

but

If

corrosion

has occurred

between

It

and

the

holding

11uds.

spray

the

area

liberally

Fig. 1.1

Cylinder, pl1ton

and

crankcase

assembly

1 Crank.case halves

2

Left-hand

cover

3

Right-hand

cover

4

Stud

- 4

off
5 Crank.case gask.et
6 Cover gask.et

7

Dowel

pin

8

Oil

level

screw
9 Sealing washer

10

Oilfiller

plug

11

Sealing washer

12

Screw -17

off

13

Screw

14

Engine

mounting

bolt

15

Spring

washer

16

Washer

1

7 Cylinder

barrel

18

Cylinder

head

19

Cylinder base gask.et

20

Spark.

plug

21

Washer - 4

off

22

Nut

- 4

off

23

Piston

24

Piston

rings

25

Gudgeon

pin

26

Circlip - 2

off

27

Engine

mounting

nut

28

Wiring

grommet

29

Stud

- 2

off

...

WD

4001 • .._

nwln

..

aence

woeol

If

nece.-y

lep

eround

N

....

ol

dw

hMd

whh e llOft

f8C8

meht

IO

etelst

In

MP818tlng

the

......

On

no

eocount

etternpt

IO

le¥9f

betwffn

the

heed

end

bafTel

r.c.:

dw

llght

~heed

Cffting

la

brint•

and H

frl

I red

4

Cl-*

lhet

the

l)itlton

la

11

the

top

of

the

bot•

If

necesurv

the

~

~n

be rotated

by

tumlng

the

generator rotor

Ult

the barrel

by

mout

an

lnd1

and

peel

eom•

d111n

rag

nto

th•

cram.ca

mouth

and around the

connect

ng rod

Th

1 precaut

on

wl I

pr

nt

any d brl1

from

entering the

cr1nlca

The barrel can

now

be I

It

d awav.

8U1JPOrt

ng

the

pi1ton

11

It

emerges

6

Ullng

rel p

pl

111

relea on

of t gudg

on

pin

clrcl

ps

The

pin

can now

be

removed

by

push ng

It

through from

th

oppos

t a de

If

the

pin

proves stubborn

warm

the

piston

by

wrapp

ng It n r g

eoaked n

very

hot

wat

r. Th 1 wl I ellpand

th

a loy and r I a

lta

grip

on the p n Place

the

gudgeon

pin

end

clrcl~

I d

th

p ton and

place

It

to

one

de

8 D

lamantling

the

engine/gearbox

unit: removing

the

flywheel

generator

auembly

N

ote:

If

th

centrifugal clutch Is

to

be

remov d

It

may

bD

necessary

to

have

the

g11nerator

rotor

in place as o

method

of

holdmg the

cr11nli.shaft

Refat

to

Section 9

for

details

Th flywheel g n rotor comPon

nts

mav

be

removed

with

th

cngln

in

or

out

of the frame

If

It hos

not

alreodv bnen

1emn11ed

It

will

be

nee ssary

to

drsmantl

th

klckstort m chanl m and romovo tho

left

hand outor covor. The procedure I

desc11bcd

In Section 5.
paragraphs 3 and 4.
2 Tha flywheel rotor

is

mounted

on

the tapered end

of

the

crankshaft. located

by

a small pin and retained

by

a single nut. When

romoving thn retaining nut

1t

will be necessary to prevent the rotor

from turning In tho absence

of

the correct holding tool (part number

732

2021 an alternative method

must

be

devised.

3

If

the cylinder head. barrel and piston

ha11e

been removed. the

crankshaft, and thus the rotor, can

be

immobilised

by

passing a

smooth round bar through the connecting rod small end

eve and

resting

the

ends on wooden blocks placed against the crankcase

mouth. The arrangement is shown in photograph

26.2c

. Another

Possible

method

is

to

use a strap wrench around the outer face

of

the
rotor.
4 Once the rotor

nut

has been removed. the rotor can

be

drawn

off

the tapered crankshaft end. The best method

by

far

is

to

use the

correct puller and this can be ordered through Tomos dealers

as

part

number

700.334.

Note

that

although there

is

sufficient clearance

to

use a legged puller, there

is

serious risk

of

damage

to

the rotor and

stator comPonents. For this reason the correct tool

must

be considered
essential.
5 Screw the puller

into

the

thread provided in the rotor boss. then

tighten the cen t

re

bolt

to

apply pressure

to

the crankshaft end.

Do

not

overtighten the centre bolt;

try

tapping the end sharply

to

jar

the

rotor

free.

If

necessary, tighten the centre

bolt

further then tap the end

again, until

it

comes free.

6

With

the rot

or

removed, attention can be turned

to

the stator.

Before this

is

removed note that

it

is advisable to mark the position

of

the stator in relation to the crankcase

by

scribing a line across

both

are~~·

This

~ill

allow

the ignition

timi

ng

to

be reset

to

its

original

p

os1t1on

during reassembl

y.

Slacken and remove the three retaining

screws and

lift

the st

ator

assem

bly

away.

9

Dismantling

the

engine/gearbox

unit: removing

the

trans

-

miuion

components

Final

drive

sprocket

.1

Not

e.

that this

operation is b

est

carried out

with

.

installed

'"

the frame because this

allows the s k

tb

he engine

f

h

d

. . proc

et

to e held

by

way

o t e nve chain and rear brake

whi

lst the s k · ·

Is

slackened (s.ee Section 5, paragraph 41. proc

et

reta ining

nut

2

If

the

engine has been removed and the

nut

h

slackened, a sprocket holding

tool

, Part Number

732

°lo~o

.

t

vet .been

from

the

manufacturer. In the absence

of

the

offici~I

·

~

available

drive chain around

the

sprocket and lock

it

b

too • loop

the

through

the

chain finks as

shown

in

photo~r~=~I~~

~dscrewdrlver

~et

In

position

, straighten the

tab

washer

and . . Hold

the

U81ng

I

30

mm

box

or

ring

spanner.

remove

the

nut

Centrtfupl

alutah

•••mbfy

3

If

the

engine

11

111N

In

the

frame drain

lhl

Remove

the

MVen

chffM

heeded

ICt9WI

which

,...,,.

die

outer cover and

lift

It

away

Note

that

the

tranarnlallon

have 1hlm wa1her1

which

m•v

11 k to

the

lmilda

of

the

are

to

reta n

theH

on

the r respect ve

lhah

anca

4 Flatten the

tab

wisher

to

allow

the

clutch

c.ntN

nut

removed

It

will be

necenary

to

prevent

the

clutch

from

turning•

nut

11

slackened using the holding

tool

732

202

referred

to

one

of

the methods deacrlbed

below

5

II

the cylinder head and barrel have been removed

PHI

•

round metal bar through the connecting rod 1m1ll end eye, au
Its onda

on

small wooden bloclur placed

on

the crankcate m

Alternatrv ly, use o

strap

wrench around the generator

rotor'•

o

foce

Wrth

tho clutch hold socurely, alacken and remove the

nut U1lng

a standard I ggod puller,

draw

tho clutch assembly

off

the

cr1nklha

h

end and ploc It

to

on

sldo.

Lift

off

tho clutch

thrull

washer and keep

h

with

thp clutch

Input

and

output

shafts

and

connecting chain

6

Th

Input and

output

shafts ere connoctecJ

by

an endless prim

chain and thus

must

bo removed as o pair. Once the centrifugal clu

assembly ha been

withdrawn

. the

two

shafts can be

lifted

out

of
casing and placed to one sldo. Remove tho thrust washer from the f
of

the Internal

output

shaft gear and place

it

over the end

of

the

ah

9.~

Remove

the

transmiss

ion s

hafts an

d di

se

ngage them

Prtmary chain

-

ChaPter

1 Engine

•nd

transmission

31

W

Dismantling

the

engine/gearbox

unit: aeperetlng

c,..nkcase

halves

the

T""

It

should be

noted

that

the

crankcase

halves

can

be

after

the

engine unit

has

been

removed

and

th

see oar111·ed· only

· 1·

'

ed

pre 1mrn

ary

dismantltng

o~era

rons

~arrr

out

as

described

in

Sections

6

10

9

2

Using

~n

rmp~ct

dnver

, slac

ken

and

remove

the

cheese-head~

screws whrch

retain

the

crankcase

halves. It will

be

found

1

..

h

· f ·

r1

· h

fi

"

11

t e

main bearrngs are a at y

t1g t 11

over

the

crankshaft

end

d

consequently a

method

of

separating

the

casing halves

m~~t

a~

devised.

3

The

manufactur~r

_

produces

a special

tool

, Part

Number

736.88

8

•

for this

purpo~e

but

rt

1s

assumed

that

few

owners

will

have access

10

it.

The

following

method

was

adopted

during

the

workshop

pro

· t

and

works

well

provided

that

reasonable

care

is

taken

to

a'e~d

damage.

If

in

doubt

It

would

be

best

to

have

the

cases

s

eparat~o~Y

a Tomos dealer.

4 Arrange

the

assembl~

with

the

right-hand

side

uppermost

. usi

ng

wooden blocks

to

hold

1t

level.

Run

the

nut

onto

the

end

of

the

projecting crankshaft

end

to

protect

it.

Assemble

a large

two

-legged

puller over

the

crankshaft

end. hooking

the

legs

over

the projecting

crankcase

flanges. Place

slips

of

wood betwe

en

the pull

er

leg

s and the

crankcase

to

protect

the

latter

.

5 Tighten

the

puller

gradually

to

eKert pressure on

the

crankshaft

taking care

not

to

overtight

en it.

With

the

pull

er

load

ed as described'

tap the end

of

the

puller

bolt

to

Jar

the crankshaft out

of the bearing'

Repeat

this

sequence

unt

il

the

cas

ing

halv

es are separated. The same

method can be used

to

displa

ce

the crankshaft

from the left-hand

casing half (see

photograph)

.

6 The

internal

output

shah gear can

be

llft

ed

out

of tho loft-hand

casing half.

If

the

various bea

rings ar

e to be removed. they can be

driven out.

using a large socket. The bearing

boss area should first be

heated

to

e>1pand

the

alloy

using

a rag soaked

in

near boiling w ater.

The

use

of a blowlamp

or

an

oven

for

this

purpo

se is

not recommended

unless the

owner

has

eKperience

of

this

method

because of the risk of

distortion

if

the

heat

is

applied uneve

nly

or

in

e>1cess

.

10.5 Use a legged

puller

to

press

out

the

crankshaft

11

Examination

and

renovation:

general

1

d

·

it

for

wear

Before e>1amlning

the

parts

of

the

dismantle

engine

un

U •

it is essential

that

they

should

be

cleaned

thoroughly.

se

~

Petrol/paraffin miK

or a high

flash-point

solvent

to

ren:io~e

all

tr:~e~n~

old oil and sludge

which

may

have

accumulated

wrthm

the

~

·

Wh

.

al

fire

precautions

ere

petrol is

included

In

the

cleamng

agent

.

nor~

a

well-ventilated

should be taken and

cleaning

should

be

carried

out

n

place. . f

2 k

or

other

srgns o

Examine

the

crankcase

castings

for

crac

s

cialist

repair.

gamage.

~f

a crack is

discovered.

it

will

requlr~

at~~e

eKtent

of

wear

.

h

E~amrne

carefully each

part

to

determ~

Specifications

section

c

eck1ng

with

the

tolerance

figures

listed

In t e

of

th~

s

Chapter or in the main tut.

If

there Is any

doubt

about

the

~~tl

on

of a partl.c11lar companent.

play

safe and

renew

.

se a

clean. hot

free

rag.

for cleaning

and

drying

the vari

ous

components..
5 V ' I

. a

no

us nstruments for measuri

ng

weer are requi

red

, Inc

lud

ing

11

vem

ier gau

ge

or

external micrometer and a set

of

standard feeler

gauges. Also an l

ntemal

and an external micrometer

will

be required

to

:.'~ck

wear

limits. Add

itionally, although

not

absolutely necessary, a

•a

gauge and

mounting

bracket

11

Invaluable for accurate

me11sure

-

ment

of

end float. and pley between components

of

very l

ow

diameter

bores.

where

a micrometer cannot reach. After some

e>1per

lenco has

been

ga

ined. the state

of

wear

of

many components can bo

determin

ed

visually

or

by feel and thus a decision

on

the

ir suitability

for

c

ontinued

service can be made

without

resorting

to

direct

measureme

nt

.

6

In

the absence

of

the

correct measuring Instruments. some

of

which may prove

proh

ibitively expensive

for

occasional

home

use. tako

the

suspect component

or

assembly

to

a Tomo1 dealer

who

will

have

the equi

pment

and

e11pertise

to

assess

its

condition.

12

Cylinder

heed: examination

end

renovation

Remove all traces

of

carbon

from

the

cylinder head. using a

blunt-

en

decl

scraper. Finish by polishing

with

metal

polish.

to

give a smooth

.

shiny s

urf

ace. This

will

aid gas

flow

and

will

also prevent carbon

from

adher

ing

so fi

rmly

In the future.

2

Ch

eck th e conditi

on

of

the

thread in

the

spark

plug hole.

If

the

thread is worn

or

stretched as

the

result

of

overtightening

the

plug.

it

can be reclaimed by a 'Hellcoll' thread insert.

Most

dealers have

the

means of providing this cheap

but

effective repair.

3 Lay

th

e cylinder head

on

a sheet

of

plate

glass

to

check

for

distortion. Aluminium alloy cylinder heads

will distort

very

eeasil;y.

especially if

th

e cyl inder head

bolts

are

tightened

down

unevenly.

If

the

amo

unt

of dist

ortion is only slight.

it

is

permissible

to

rub

the

head

down

until

it

is flat

once

again

by

wrapping

a sheet

of

very

fine

emery

cloth around the plate glass sheet

and

rubbing

with a rotary

motion.

4

If

the cylinder head is

distorted

badly,

it

is advisable

to

fit a new

replacement.

Although

the head

joint

can be restored

by

skimming

.

this

will

raise

the

compression

ratio

of

the

engine and

may

adversely

affect performance.

13

Cylinder

barrel:

examination

and

renovation

EKam

ine

the

bore surface

for

wear

or

damage

.

If

scoring

or

other

serious damage is discovered.

it

will

be

necessary

to

have

the

cylinder

bored oversize and a

new

oversize

piston

fitted. This

work

should

be

entrusted

to

a Tomos dealer

who

will

have

the

necessary parts and

machining

facilities.

2 Normal

wear

over

many

miles

will

cause a small ridge

to

form

near

the

top

of

the

bore,

marking

the

extent

of

piston travel.

It

is possible.

with

practice,

to

determine

whether

the

bore

is

serviceable.

but

if

in

doubt

seek

the

advice

of a Tomos

dealer.

J

If

measuring

equipment

is

available.

note

that

the

maKimum

permissible

bore

ovality

Is 0.

006

mm

(0.0002

in) and

the

ma>1imum

allowable

bore

taper

is

0.006

mm

(0.0002

In).

4

Where

a bore

is

to

be

reused

in

conjunction

with a new

piston

or

new

rings.

it

Is possible

that

the

wear

ridge.

if

excessive.

will

fracture

the

new

top

ring. A

Tomos

dealer

will

be able

to

advise

on

this

point

if

there is

some

uncertainty. Generally speaking.

the

best approach is

to

rebore,

but

it

may

be possible

to

have

the

ridge machined

away

by

a local engine reconditioner.

5

To

ensure

that

the

new

rings

bed

in

correctly,

it

is

important

to

remove

the

surface glaze. preferably

by

honing.

If

necessary.

this

process can be approKimated

at

home

by

careful use

of

fine abrasive

paper. Rub

the

bore surface

with a rotary

motion

until

the

surface

is

lightly

scratched along

its

length

and

remember

to

clean

off

all traces

of

abrasive

prior

to

reassembly.

14

Piston

and

rings:

examination

and

renovation

If

e>1amination

of

the

bore

surface

has

Indicated

the

need

for

reboring,

this

Section

can

be

ignored. since a

new

piston

will

be

'2

C~pter

1 Engine and transmission

It

lh

d p

ould

be

""

to

move

n their

groo

e • t

hough

the _,.. N

n1

fr ' ro11

11ng

in use b

small

pins. These

slop lhe

ro1n

bee

"ng

cau

ght

n 1he

ports

If

the

rin

gs

are trapped

th

1 m

a,

be

du

to

bunlng

of the pi

ston mater

ial cau ed

• •e Of b'

gumming

due

to acc

umulated

o I resi

due

.

•tnQ

uld

be

removed

to

allow

the

grooves

to

be

cleaned

and it are Is tak n

th

is

can

be

accomplished

by

e

1ng

th nr g

tmd ltghtly

with

the

thumbs

and

lihing the ring

1 A

~at

r n et

hod

In 1

ew

of

the

brittle

nature

of

the

rings is to use

thr9e

l m

l~

I

111p_ uch

Ill

old

feeler gauges. as

shown

in

tho

M-<-nn

,nanymg line

drnwlng This

method

ls

a useful

woy

of treeing

ri g

Trtlrn

care to ensure 1hat

rings are marked to

indicate

t

oi

upper surfa

nd

1he correct

poslllon

on 1he piston This can bo

t>',

~

r I

ng them

· I .. and

··1r·

using

11

splrl1-basod felt pen

6

C;m~rull~

le n o

ul

lhe

ring

grooves

before

refitting the pist

on

riog_

"' I

figures

11re

11v11ilab

le to indica te

1he

allowable ring to

g

Yt~

cle

nr, n e.

but

as

o

rough

guide the

maximum

clonrance

on

n

1I

Jr

on9iMs

is

ilbout

0

05

mm

(0.002

In).

If

greatly

in

oxcoss of this,

r

en

ew the P•-t

on

Gild r

ings

ns an nssembly.

If the pist

on

is

to

be

reused, clean

otf

any accumulated carbon

fron

tt l'O\ n usi

ng s blunt

scraper. and

111k

ing care

not

to

dig into

th

e piston

m teriat.

If

desired. a

mo111I

polish can be used 10 give a

bright fin

ish This '

ill redu

ce subseq

uenl

carbon build-up

.

15

Crankshaft

assembly: examination

and

renovation

1 The crankshaft

is

unlikely

to

require

attention

unless as a resull

of

serious

mechanical

damage

or after a very high mileage has been

CO\-ered. The

com

ponent

most

likely

to

wear

is

the big-end bearing.

especially

where

lubrication has been inadequate. A

damag

ed big-end

bea

ri

ng w

ill

not

normally

go

unnoticed. emitting

a c

har

acteristic

clicking

or

knocking noise

and

causing vibration

which

may be

felt

through

the

frame

when

the machine is ridden.

2 The

big-end

bearing

should be examined

for

radial play

by

grasping

the

con

necting rod

and

attempting

to

move it

up

and

down

in relati

on

to

the

flywheels. Any

detectable

movement

in

this

direction

is indicative

of a badly worn

big

-end bearing,

and a new

cranksha

ft

assembly

will

be

required.

Note

that

a small

amount

of

end

float

is

normal. and care should

be

taken

not

to

confuse

this

with

the

radial

play

described above.

3

ti

there is reason

to

suspect

the

crankshaft has been

distorted. ils

ali

gnment

can

be

checked

by

placing

it

between

centres

and

checking

for

run-

out

as

shown

in

Fig. 1.5. The

maximum

permissible

out-of-

round figures are

0.

01

mm

(0.

004

in)

at

points 2

and

3, and 0.

02

mm

(0.

0008

in) at

points

1 and 4.

In

view

of

the

need

for

specialist

equipment. professional help

will

be

required

for

this

check.

16

Small-end

bush:

examination

and

renovation

1

.

sm~ll

end

b~sh

wear

is

char11cterised

by

a metallic

rattle

when

the

engine

is

ru~

.

If

in

need

o~

renewal.

the

old

bush can be

drawn

out

of

the connecttng rod eye using the special tool, Part

Number

708.253.

or

a.

drawbolt

arrangement as shown

in

the

accompanying

lin

~ng

.

e

2

Draw

the

new

bus~

into

po~ition

,

then ream

it

to

1O.O1

_ 1 0.

02

mm

(0.

394

1

~

0.3945

1.nl. Once mstall.ed, drill

two

lubricating holes

to

con:espond

with

those

in

the connecting rod eye.

In

most

cases

it

is

easier

to

take

the

crankshaft assembly (or the complete engine ·

the cylinder head. barrel and piston)

to

a Tomos dealer

for

a

new"'~:~~

to

be

fitted

and reamed.

0 38

(1.

496

1n

)

Fig

. 1.2

Piston

wear

check

measurement

points

...

··

..

.

Fig

. 1.3

Method

of

removing

gummed

piston

rings

5

Fig.

1.4

Crankshaft

1 Crankshaft

2

Small-end

bush

3

Main

bearing - 2

off

4

Oil

seal - 2 off

5 Thrust washer

....

1

2

3 4

t/

Fig.

1.5

Checking

crankshaft

run-out

- see

text

2

3

6

. ·. . . .

..

. .. . . ·. :

··.

1

4

5

"·

.

...

Fig.

1.8

Drawbolt

arrangement

for

removing

the

small-end

bush

1 Extractor

bolt

2 Bush

3 Rubber washer

4 Tube

5 Washer

6

Nut

17

Main and

gearbox

bearings

and

oil

seals :

examination

and

renovation

l T

ft

in their housings and

he

various bearings are an interference

1

h t each one in

may

be

checked for

wear

whilst

in position.

w_as

·n outhem

by

hand.

~ean

Petrol. then check for play and

wear

by

spi~~a~

but any radlal

small

amount

of

side-to-side

movement

is

no •

play or roughness is indicative

of

the need

for

renewal.

2 To remove the bearings. heat the casing around

the

bearing. using

n

ea

r boiling water. taking care

to

avoid scalding. Support the boss area

well. then drive out the bearing using a large socket. The

new

bearing

c

an

be fitted in a similar manner. taking care

that

the bearing enters
its bore squarely and fully .
3

The

oil seals must be renewed together

with

the bearings. and

it

is

good practice

to

renew them as a precautionary measure whenever

the engine is overhauled. Take care

to

avoid damaging the seals during

fitting. and remember

to

lubricate the seal

lip

with

grease prior

to

reassembly.

1 7. 1 Check the bearings for wear and renew

if

required

Clo•

1

...............

I 1'111

11

Cu

'1

11

1111

:wa

••

Ill

rdan

_...

•••••dol•

19

Centrlfug•I clu

tch

HHmb

ly· d11manthng,

o\l•rh•ul •nd

,

..

n•mbly

t

Th

c ntrlfugal clutch control tho

ou1oma11c

clutch operation

when

moV1ng

off

from r

lit

and tho change botwoon

low

anrl high gear.

If

thoy ho bocome rratlc

In

op

ration they should ho

di

mantled and

checkod as de

cnbcd bolow

2 R

mov

the clrclrp b

twl'on

th

two

gears on tho inner face

of

the

assembly end parate

th

clutch hubs from the drum The

two

du

tches are dismantltJd In a similar manner,

but

should be dealt with

scparat

fy

to

avoid interchanging parti;.

3 Using a screwdriver, hft the spring band over one

of

the ·ears'

of

the guide strips and remove it. Note the position

of

the guide strips,

they ere

amm

ged so that they overlap each other and must be refitted

in

the sa

me

manner. Remove the strips and place them

to

one side. To

free

the

indi

vidual shoes from the hub press out the pivot pins and

lift

the shoes

away

.

4 Examine the

fr

iction surface of each shoe.

If

they are badly worn

they

should be renewed as a set.

No

precise wear limits are available,

but

the p

ivo

t end

of

each shoe will be relatively unworn and

will

thus

grve a

g

ood indicat

ion of the exte

nt

of wear

If

the whole clutch

assembly

appears worn

or

is sloppy in operation.

it

shou

ld

be renewed

as a unit.
5

If clut

ch slippi

ng

has been noted and the shoes appear relative

ly

unworn. renew the spring band as a precautionary measure. N

ote

that

the

outer

clutch (clutch

I) controls the initial movement from

rest

whilst the

inner

clutch (clutch II) is responsible f

or

the change

to the

higher gear

If

either operation occurs

lat

e,

renew the spring band
concerned.
6 The clutch drum unit incorporates a small roller

clutch

whi

ch is

designed

to

allow

drive in one direction only.

If

this is damaged

or

suspect,

it

is recommended that a Tomos dealer should be consulted.

This is because a press

will

be needed

to

remove and

fit

the

roller

clutch. For owners

with

access to a press, note

that

the roller clutch

must be

fitted

with

the marked face innermost.

If

this is

not don

e,

the

clutch

will

operate in reverse.

7 When reassembling the cl

ut

ches,

it

is far easier

if

the assembly

tool

, Pa

rt

Number 731.

798

, is

ava

ilabl

e.

When assembling c

lut

ch I,

clamp

the support h

alf

of

the tool in a vice

with

the

projecting lug

downwards. Place the clutch hub over

the support,

not omitti

ng

the

thrust washer, fit the shoes a

nd

position the guide str

ips

so that they

overlap and

hold

each

oth

er in place. Using the handle pa

rt

of the tool,

flt

the spring band, ensuri

ng that the

join

is

fitt

ed

at

the ce

ntr

e of o

ne

of

the shoes.

8

When

dealing

wit~

clutch

II

the procedure is s

imilar, but

note

that

the

support should be inverted

and

the

lug

engaged

in

one of the gaps

between the shoes.

Use the handle secti

on

to

fit

the

spring band as

described above.

9

In

the

absence

of

the

correct

tool

it

Is possible

(though

not

easy)

to

auemble

the

shoes, guide strips

and

spring bands

by

hand.

With

an

19.3a

Work

the

spring

band

over

the

guide

strip 'Mrl

19

Jb

Uft

oot

the

guide

strips, noting

relative

posit

ion

s

Fig.

1. 7 Centrifugal

clutch

1

Bush

2

Clutch

drum

3

Roller

clutch

4 Thrust

washer

5

Shoe

- 6

off

6

7

8

Boss
Pivot

pin

- 6

off

Tab

washer

9

Nut

10

Clutch

bearing

11

Retainer

12

Guide

strips

- 6

off

13

Spring

band
14 Boss
15

Circlip

2

H/b.q_7b

19.Jc

Press

out

the

pivot

pins

to

free shoes

from

boss

7-#

20

y, • ..,...r:ain

ews ..tet

,.,..,

dll1dl

dismending.

~

9ltd

111w1mbfy

20

.1 b Lever

off

the 2nd gear pinion using screwdrivers

- -. .

20.2b ... disengage spring end and lift

off

the

sprocket and

II

· ro

er

cage

20.4a

Place r

oll

ers in

pos

iti

on

...

20 G II

al

vo

g r h

nrin11'

1

110

worn or d1irnegotl, ronnw the aloove

11r

os an

11s11ombly

Fig.

1.8

Tran1mi11lon gears

and

roller

clutch

1

Input

shaft
2 Woodruff key
3 Bearing

4 Circlip

5 Chain sprocket

6

Input

shaft 1st gear pinion

7 Roller

(8

off)

8 Wire spring

9 Spring retaining plate

10

Rivet 4

off

11

Tab washer

12

Nut
13 Thrust washer
14 Bearing
15

Input

shaft

2nd

gear pinion

16

Output shaft sleeve gear

1

7 Sleeve gear bearing

18 Final drive sprocket
19

Tab

washer

20

Nut
21 Distance piece
22

Oil seal

23

Roller cage

38

Ch8pW

1 Engine

end

transmission

21

Klc:btart

med\enism: eamination

and

renowtion

E.u

mtne

it.

ratche

t t

tt

fOf

59'S

of

n>uJdng

off. 1

common

cav.te

of

pping • t

1rt

rit

dte

ts.

If

damaged.

renew

the

r1tchet

bfoclt

1:nd •

Ito

the

outDvt

&haft

~

Qe•

11'1d

tile

sprodlet

if

t.he

corr

~

ee i

re

da:m~

01edl

ttuit

the

fricti

oo

d ip grips

t.he

ratc:N! blocl!;

irmty

Note tf\11

tt>e rat

chet

blodt

must

be

poslt

iooed

f

f'IC1

oao cGo

~

away

from

the

IJ)f'Odet.

22

Engine

,...

...

mbly:

general

~

1 Before reassembly

of

the

engine/ge

-

~

various

component

parts

should

be

clea~:x

Unit

is

Co

a sheet

of

clean

paper

, close

to

the

work!

thorough!

fllrne

~

2 Make sure

all

traces

of

old

gaskets h ng

area

. Y a

r\d

DI~

the

mating

surfaces are

clean

and

unda ave

been

re

·

taken

when

removing

old

gasket

compo

mdaged. Gre81rn

°"eti

a

~

un not to d

care

!I... t

arnage

the

..._

.i

q•

5 8

<BT({

(c)

3

~6)

~~

1

Output

shaft

2

Needle

roller

bearing

3 Needle

rol/tu

bearing

4 Thrust washer

5

Spacer

6 Sleeve

7

Kickstart

lever

8 Ki

ckstart

lever rubber

Fig. 1 .9

Kicks•-"

...

•ssembl

9

Y

and

output

shaft

Nut

10

Washer

11

Bush

1

2

Cotter

pin

13

Spring

14

Detent

Pin

15

Spacer

16

End

cap - 2

off

1 7

Return

spring

1

8

Sprocket

19

Primary

chain

20

Friction

clip

21

Ratchet

block

2

2

Outer

plate

2

3

Spacer

24

Nut

~

16

25

Spring

washer

26

Screw

27

Screw

28

Sleeve

29

Spacer

30

Spacer

31

Shim

c....,_,~

~

8nd

11tr:n••=•••-

..._

gesket

compoonds

can

be

90ftenect

~..,ch

as

methylated

spirit.

acetone

or

celluio..,"*tg •

SUitable

d

..,tvent

requ

red

will

depend

on

the

type

f

thinners.

The

f'lfl'

~

of

the

non-harden"ng

type

can

:,

<:omc>ounct

Wed

~

~-wtre

bnsSh

of

the

type

used

tor clearnng

~

usmg a

~~

amount

of

scrubbing

can

ta

e plaoe

wi

shoes.

A

cor-'"'"-tf,e

mating

surfaces.

Some d fficulty

may

be

thout

fear

of

:=:::nemptmg

to

remove

old

ga

ets

of

the

self-vu1C:~ntered

of

which

ls

becoming

widepsmad

partlculart

ng

tvPe.

:;!i

':'-gaskets

The

gas

et

should

be

pared

from

t~:~~~inder

head

dtl!I

1

sea

pel

or a small

ch

el ~ th a finely

hone<1

d ng surface

~

resort

to

scraping

with a sharp

instrumen

t unl:ssge.

Do

no

Gittler together all

the

nee

ssary

tools

and

have ava

~ry

.

3

ed

with

clean

engine

011

Ma

e sure

that

all

new

gft_._8 e an

°~

1

Cl:'I

nd

1-

II I

~ets

and oil

-~

•~

to

ha h. a

so a rep

a~cm

nt

pans

required

Nothing

is

more

!nJStrll!ng than

1

a

n:

to

stop

1~

the m ddlc

of

e reassembly sequence

beC-luse 1 ta

gas

et

or

rep

acement

has

been

overfooke<I A

gtnenl rule

each

moving

engine

component

should

be

hrb·. s

8

rtiorOUQh

as

It

is

fitted

into

position

ncated

" t e sure.

that

the

reas..;embly area is

dean

and

that

there

is

~ate

v.'Or

mg space. Refer

to

tho

torque

and

clearanrft

·

M

1

..

....., settings

"f!el'f\1!T thev are given.

any

o.

the

small

bolts

are

eas

1y

sheared

if

(!l'e(l-ghtened

Atwa~s

uo::e

the

cor~ect

size screwdnver

bit

for

the

24

1 Place the cran shalt in po<:•tion In the left·hand casing

half

cross.:tiead

scr&\\S

an~

ne~er

an

ordinary

screwdriver

or

punch

If

the

e'.st

og

scre\\S

shoVI.

e\1dence

of

maltreatment

in

the

past.

at

15

adl

,51b)e

to

renew

them

as a complete

set

It

is strongly

(!COOUTlended

that

if

renc\\al

of

the

screws

is

required a set

of

Allen

~sis

purchased

instead

Allen

screw

sets

are available through

::iost

good accessory

retailers

and

are

an

inc

..

pensive

but

thorough!

.

l.

J y

pract

ca

1mprm.ement

to

most

apanese machines.

23 Engine

reassembly: refitting

the

main

bearings

and

oil

seals

1nd checking

crankshaft

end

float

If

the crankshaft

main

bearings

are

to

be

renewed.

warm

the

bearing

bosses

then

tap

the

bearings

into

position

using a large socket

as

a

drift.

Ensure

that

the

bearings

enter

their

bores squarely and seat

fJ .

2 ote that

if

the

main

bearings

crankshaft

or

the

crankcases have

been

renewed. it

will

be

necessal)

to

check

the

crankshaft endfloat.

Th's

requires

the

crankshaft

assembl\

to

be installed and the

cran

cases

assembled as

described n Section

24

noting

that

it

will

s~ffice

to secure

the

cases

with

the

three

screws adjacent

to

the

crankshaft.

3 Arrange a dial

gauge

against

the

end

of

the

crankshaft and note

the

total endfloat

present

If

this

exceeds

the

permitted

clearance

of

0 02 - 0.12

mm

(0.008 -0.004 7 'n)

fit

the

necessary shims behind

the

main bearings. These are available

from

Tomos

dealers

in

0.1

0.15

arid

0.2

mm

(0.004

0.006

and O 008

inl

sizes.

4

Once

the

endfloat

has

been

checked

and

adjusted.

the

crankshaft

oii

seals

can be

fitted.

These

should

be

renewed

as a

matter

of

c~urse

each

time the

engine

is

dismantled.

Lubricate

the

seal

lip

s w

ath

a

sme

ar of grease

prior

to

installation.

The

left-hand

seal must be fitt?d

With

its spring side

facing

inwards

whilst

the

right-hand seal has its

· · large

S?rmg

side outwards. Press

the

seals

home

carefully us

ing

a

SOck.et as

a drift.

24

Engine

reassembly: jo

ini

ng

the

crankcase

halves

1 Pl rkbench supporting it

ace

the l

eft

-hand

crankcase

half

on

the

'!"

0

.

~kshaft

.

Place

:'

WOoden bloc

ks to leave

room

for

the proiec

ting

c~a

th

t the big

e crankshaft end

thro

ugh

the

main

beari

ng and

turn

it

50

:tal

strip

~nd

bea

ring is

opposite the crankcase mout

h.

Plac~ a ~otograph.

Th~n

the

flywhee

ls as shown

in the

a

c.c

om~an~~~

:s

it

is fitted.

2

IS

Will

prevent

any risk

of

the cranksh

aft

being

distod

nd

use

this

to

~lace

a

length

of

tubing over the

c~

ankshaft

e~

~Uy

and

that

it

tu

the

crankshaft

home

. Check

that

1t has seat u h

its

bearing.

Pu':·

~

·

Fit

the

output

shaft

sleeve

gear

~=':.!ve

gear

needle

rol~ng

•t fully

home

. Pl

ace

the shim

washer

on

t

3

bearing.

I

wer

the

rtght-hand

era

Place

a

new

gasket

over

the

joi

nt

face. then

~Ing.

tap

the

casing

ha~

half

into

position.

Using

the

l~n~th

of

tuws.

tightening

them

flven

down

until

it

seats

fully.

Fit

the

retaining

sere

ly and progressively.

24.2a Support flywheels

with

met

al strip (arro

wed

) as sh

own

. Use

tubing

to

drive crankshaft home

24.2b

Lower

the

sleeve

gear

into

its

bearing .••

24

3

b Use tubing

as

a drift to close joint

25

Engine reassembly·

refitting

the

transmission

shafts

and

centrifugal clutches

1 Assemble the input and output shafts, joining them

with

the
endless primary chain. Lower the assembly into the casing, ensuring
that the kickstart friction clip lo

ca

tes between the

two

raised

Jugs

forward

of

the output shaft bore.

2 Place the washer and the sintered bush over the end

of

the

crankshaft. then slide the

ce

ntrifugal clutch drum complete

with

the

Inner clutch into place. Check that

it

meshes correctly with the input

shaft gears . Place the shims over the !!haft end, then

fit

the outer

clutch into the drum.

3 Fit the plain washer, tab washer and the retaining nut. Hold the
crankshaft to prevent rotation,

th~n

tighten the retaining

nut

to 2.5 kgf

m (

18.0

lbf

ft) Send

up

the lockrng tab to secure the nut.

4 Check that the clearance between the clutch drum and the shoes

is

approximately 0.4

mm

(0.0157

in).

The end float

of

the clutch d

should also

be

checked.

~his

should be .from 0.1 0.3 mm

(O.O~~m

0.

012

in) and may

be

adiusted

by

altering the thickness

of

the shim

washer between the outer clutch and the drum. Shim washers

available in

o

..

3 and 0.5

mm

(0.012 and 0.

020

in) thicknesses. are

5

Fit the shims

to

the end

of

the Input and output shafts

Pl

new

gasket on the

joint

f~ce

,

then offer up the outer cover.

Chec~~~a~

it

has seated fully, then

fit

and tighten the retaining screws.

24

3a Lower casing

into

position

25

.1 a Loop

the

primary

chain

around

the

transmlssk>f'I

-----

--------

---__,..

r

-~

1

~

If

2

s.

1b

...

and

lower the

assembly

int

o the casi

ng

recess

2

5.2b

Check

that

the

shim

is

in

place

between

the

drum

and

outer

clutch

...

25

.2a Fit the wash

er and sintered bush

over

the

crankshaft

end

25.2c

...

then

fit

the

assembly

over

the

crankshaft

end

'

'

l

I

I

I

I

l !

2 5.

Sa

Place the shim over the end

of

the

output

shaft

...

25

.Sc Place a n

ew

cover gasket

in

position

...

Chapter

1 Engine

and

transmission

.

43

~embly

:

refitting

the

flywheel

generator

aasembly

f11g111e

re

___________________

_:.

26

bl . h .

enerator stator assem Y rnto t e casing recess. routing

1

fit .

the

~rough

the slot

at

the

top

of the casing. A

lign

the

scribe

ttie

~innQ

t during removal. then

tighten

the

retain

ing

screws.

Note

:

made

· · · h

ffi

·

1118

~s.

the

ignition

t1mrng

wit

su

1c1ent

accuracy

to

allow

the

lhi

S

will

sebt

run when reassembly

is

complete. It

is

import

ant

to

· e

to

e · · • h k d

,

og1n

the ignition

t1mrng

ts

c ec e as soon as possible. Refer

to

re

that

.

,osu

3

for details.

Chapter

the generator rotor,

making

sure

that

it

engages over the

2 . .

otte~:~n

the crankshaft end. Fit

t~e

washer

and

the reta ining nut.

drl'llflll

P h crankshaft

to

prevent

1t

from

turning

as

the

nut

is

tiofdillll

I e

tightened.

2

6.1b

Align

the earlier made reference marks then tighten

the

retaining

screws '

26.2b

- -

..

. then fit the washer and retaining

nut

26

. 1 a Offer

up

the stator

asse

mbly, pus

hing

the

wiring

grommet

into

its recess

26.2a

Pla

ce

the rotor over the cranksh

aft

end ...

26.2c Lock the crankshaft and ti

ht

h . .

g en t e

retaini

ng

nut

C"8Pt8' 1 Engine

and

trensmisalon

-

Set

the a1nklhaft

it

toe>

deed

centre and

pa0-li.

the

crankC!'se

mouth

with

dun

reg o catch

•11Y

ccid

nta

dropped

clr.chps

Lubricate

the

sma

end

bush

"'

th

eng

ne

oi

Offer

up

the piston.

noting

that

the

1rrow

mark

on

the

crown

must

fee rorward Push the

gudgeon

pin

through

the

gma

end

bush

warming

the

piston

1f

necle

rv

to

eue

fittlng

2 Reta

gudgeon

pin u

ng

new

circlips Ensure that the circlips

teat

fu n t r groove•

and

that they ere curel

In

position

3 P tion

the

piston r s so

that

th

ends

co

nclde with

the

location

ra

R move t rag from the crankcase

mouth

end lubricate

t e piston and

cy1

nd

bor

with

eng

ne oil Place a

new

cylinder base

g

Ml

n po

uon

4

Ott

r

up

the

barr I I

ed

ng

th

nngs

Into

tho tapered lead-in

as

the

P

on

ent rs the

bor

On

the

nngs

ar well inside

the

bore. push

th

barrel down against

th

ga

ct

5 Plaoe

th

cyhnd r h

ad

ov r

th

hold ng

studs

ht

the washers and

run

th

nuts

onto

th

studs Tighten the cy1inder head nuts evenly and

progr

1voly

in

a diagonal

Gequencc

to avoid warpage

The

final

torqu

ftgur

I 3 0

kgf m 121

7 lbl ft)

f

2 7 1 b

dOffer

up

the

piston ensuring that the arrow

ma

k f

orwar

..

r aces

2 7 .

4a

Offer

up

the cylinder

ba

I .

rre

• using a new b
ase

gasket

Chapter 1 Engine and tran . .

sm1ss1on

nd

tighten the retaining

nuts

in the sequence indicated

21.4c

...

a

28

fitti

ng

the engine

unit

into

the

frame

1

Lodge

the

plastic intake silencer inside

the

lower

frame

member

.

Uthe

carburettor

was removed. refit

it

to

the cylinder barrel stub. using

1

new

gasket

on

the mounting flange. Fit

the

air filte

r gauze

into

the

end

of the

carburettor and check

that

the

black

rubb

er intake hose is

in

pl

ace

on

the

intake silencer stub. Place the engine

mounting

bolts

wi

th

in

easy

reach

of

the frame.

2

Lift

the

engine unit into position and hold

it

in place

with

the

two

upper

mounting

bolts.

Work

the

intake hose over

the

end

of

the

carburettor.

Fit

the remaining bo

lts. not

ing

that

they

should be pushed

through

from

the left-hand side and

that

the

lower bolt

also reta ins the

centre

stand

return spring anchor

plate

.

3

Fit

the

moun

ting bolt

nuts

and washers

and

tighten

them

securely.

U

si

ng pliers. refit the centre stand return spring. Slide

the

carburettor

thrott

le

valve

into the body,

fitting

the

knurled

top

hand-

tight

only

.

Reconnect the

generator

wiring

at

the

connectors

on

the left

-hand side

of

the

machine.

4

Reconnect

the fuel feed pipe. using

new

sealing washers

on

the

ban

jo

union.

Fit

the spark

plug

cap.

Refit

the

channel section

below

the

~e

l

tank

, noting that the

HT

lead is routed

up

and

through the slot in

rts left-hand

side.

5

Assemble

the exhaust system using a

new

exhaust

port

gasket.

Once

the

two front and single rear

mounting

nuts

have been fitted

~sely,

tighten them securely, starting from

the

front.

Pl

ace

the

distance piece and final drive sprocket over the splined

~d

~f

the

sleeve

gear.

then

fit

the

tab

washer

and retaining

nut

. Loop

s

·de nal drive

chain

around

the

sprocket and

refit

the

joining link and

1

e

Plate

Ft th · d f ·

the

dir : 1 e spring clip,

noting

that

its

closed en

must

ace

in

7

ection of chain travel.

On

ce

the

ch

· h · · ·

'th

t

he

a

in

as

been refitted

it

can

be

used

in

con1unct1on

w1

rear

brake

t h

Id

· · · t 's

secur

d o o the drive sprocket

whilst

its

retaining nu 1

8

Ref

.

~ghten

the nut firmly

then

lock

it

by bending over the tab.

e

erring

to

Ch

' h

ssa

ry

adjust

the

. . . apter 3

for

details. check and w ere nece.

l

eft.hand

ignition timing.

When

this

has been set correctly. refit

the

9 A outer cover.

ssemb

le

th

k' k

f'tf

g

thern

ov

e

1c

start return spring and

its

two

end caps, 1

in

lllaking

er

the

shaft end. Place

the

kickstart lever over

the

shaft end,

the

con:~r~

that the return spring

end

engages. Turn the lever until

the

kicks

ttn

can

be

inserted. Tap the pin

into

place, then check

that

and

nut

an

rt

ope

rates normally.

If

all is well. refit

the

cotter

pin washer

10

Check d secure

the latter.

the

level

,that the transmission oil drain

plug

is secure and

remo~e

transrnis ~ ug.

Add about

200

cc

It

Imp

pint)

of

a Type A automatic

When

th!1~~

!luid

(ATF)

or

SAE 1 OW

30

motor

oil. The level is

c~rrect

l

evel

Plug 1 Just

begins

to

emerge

from

the level

plug

hole. Refit the

11

R •

h

e~~

h

s

Ou

ld

be

~footrests

on

their

frame projections. noting

that

t . ey

~vers. Ma~

set upwards. Refit

the

right-hand and left-hand

en~~ne

35

been

f e a final check around

the

machine

to

ensure

that

not

ing

orgo

tten.

28

. 1 a F

it

the intake silencer into t

he

bottom

of

the

frame

28

.1 b

If

the carburettor

was

removed,

refit

it

to

the

intake

flange

-

J..>

28.2a Lift the engine

into

pos

ition

and

refit

the

mo

t' b

1

un

mg o ts

.

..

.

....

45

I "

28

2b

Do

not

omit

the

oMh I

ad

tag

under the head

of

the upper

mountmg

bolt

•.

28.5

The

silencer is retained

by

a single

nut

28

·

6

C Fit the tab washer and retaining

nut

k

the

sprocket

with

the final drive chain and tighten the

2s.6d

LOC

reta

ioi

l19

out

28

.8

Once

the

timing has been checked. refit

the

outer cover

28

.7 Secure the nut by bending over

the

locking

tab

28.9 Fit the kickstart return spring and end caps

fng

that they should

be

offset upwards

28.

11 Fit

the

footrests.

no

1

--

···

----------------------~

ChaSJU' 1 Engine

end

trensmission

rl for •

few

mom.nll

to al

low

the

St

•:n

the

~

us,.ng

the

norm

al cotd

start

1 m

ay

be

oeceuary

to

perHvere

fot a

while -

do

1 lhtore s

Ao

sign ~ fe

during

the

fim

few

attempts.

ne

f to

stFt.

~

th

at

the

sp.eril

plu

g electrodes

not

boeoom

e l

outed

by

excns

oOl

11

sed

during

assembly

If

this

fails

e e

0<1

m.

the

Hl

oonoection

. wui

ng

connections

Dl)ly

, u:wng

~

fault

d~

Se

ction

'°'

guid ance .

.

..

3

When

the

eng

ine does

start. run

it fairly

51

the

first

few minutes

it

will

probab

ly smoke

~wly

for

a

ifi

h·

oil

is

burnt

off

. There is

no

cause

for

alarm lllewha1

as

11

~

~

••

subside. Check

around

the

engine

for

leaks

or

b.I

th

~

srrio~

8

8

1'fr

t,

run the engine within a

confined

space.

owing

gaSke

.,,.

t:

4

St

op

the

engine

and

lea

ve

it

to

stand

for a f .

lt

D:

.

th

e transmissi

on

oil level. Check

tha

t the brake

ew

rninutes.

lh

system

function

normally

before

taking the ms.

~~rottle

a

lld

ent' ,

S Duri

ng

the

flrst

few

hundred

miles

treat

tha

c i

ne

on the

elt

~:·

• • · e mach·

ro~

new

. The various

new

or

disturbed

parts

will

ne d

1

ne

as

if.

properly.

requ

iring a

gentle

throttle

hand. Not e a

chan

ce

t q

°"

·

eng

ine is

rather

vulnerable

during

the first

fee

tha.t

any

lw

0

lit

~

·

It · th

· · w

miles

0.1~.

pathetic use

may

resu m e

engme

s seizing · a

nd

·

6 Keep a careful eye

on

all fasteners.

tight~n

i

n

~n r,

loose. Check

the cylinder

head

nut

torque

settin ~ any Yihieh

~

·

miles have

been

covered

and

at

the

same time

re~d

.

afte

r

a

botJ1 Ir

whi

ch

may

have

settled

in

use.

Just

a

ny

ton-

~

chapter 2

Fuel system and lubrication

~

·7~:~:e,S:i~~i~~

~j~~

-~i

~~

·:

::::::

::

::::::::::::·

.:::::::

:

:::::::::::::::::::::::::::::::::::::

~

F

:i

pipe: examination and

;.e~ewal

.......

..

........................................... 3

Ca

rbU

rettor: removal and re 1tting .......................................... .............. 4

Sp1Cifie8tlons

Fuel

tank capacity

Main

supply .....

...... · · ·

···

· · ·

··

· ·

·· · ··

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

··

· · · · ·

··

· · · ·

··

· · ·· ·

··

···

· ·

···

··

· ·

Reserve

supply .......................

................................................................... .

Clfburettor

Si

ze

.............................................................................................................. .

Main

jet ............................

...

......................................................................

..

Air

filter

Type .....

.....

................................................................................................... .

Engine

lubrication

Type

.............................................................................. .............................

..

.

Mi

xture

ratio ....

.....

....................................................................................

..

Oil

type ....................................................................................................... .

Transmission

lubrication

Oil

grade

............

...

.......

............................................................................... .

Quant

ity

.........

.........................

.......................................................

...........

.. .

G111eni1

description

fr

The

fuel

system comprises a

petrol

tank

incorporated

in

the main

arne

· • •

th

f1o

spine

. from

which

the

petroVoil

mixture

is

fed

by

gravity

to

e

th

at

chamber

of

the

carburettor

. Fuel

flow

is

controlled

by

a

r

~sition

fuel tap,

providing

Off. On

and

Reserve settings. .

ca

s1 in

ca~urettor

is

of

conventional

design. the

float

chamber

being

lll<>peo

uni~

With the

main

body. In

common

with

most

Eur~pean

main · designs

it

is

a very

simple

instrument.

having

only

a single.

vaive'

/

8

1

~

·

Additional control

is

provided

by

the

cable-operated

throttle

•.

1

8

Ide). No

throttle

needle

or

needle

1'et

is

fitted

. d

"'r

ent

· . . ·1 I regnate

gauze

Iii enng the engine passes

through a simple

0

1

-

mp

. .

1

le

1 ter ele . . d

st

and

1s

eas1

Y

c

aned

.rnent.

This

removes

any airborne u . h a

Pl

astic

· to maintain efficiency.

Air

is

ducted

to

the

filter

throug

intake

·

1

·

The..

.

St

encer housed

in

the

main

frame

section. . d on the

en..

•uel

cont . f 'I Th'

is

depos1te

-

..,,ine

int

ains a

small

proportion o 01

. 1s.

.

'thout

the

e~nse

ernals

during use

providing

engine

lubncat1on

w~

Tomos

rn

Od

and

c

1

• • .

1

mp

Certain

d

r"

els. not

1

ornp

ex1ty

of

a separate

01

pu

· b . ation system

i

ven

Off

thernP<>rted

into

the UK.

employ a pump

lu

nc

generator

rotor

unit.

Carburettor:

dism1ntli~g

.

eumln1tlon

end

reeuembly ...

....... ·········

Carburettor:

adjustment ...

..

........

...........................................................

..

Air filt er: removel end cle1ning ....................

...................................

....

..

Exhaust system: maintenance ..........

......

............

....

.............................. .

4.0 litres (7.

04

Imp

pints)

0.5 litre

(0.88

Imp

pint)

12

mm

(0.47

in)

46

Oil-impregnated gauze

Premixed

two-stroke

oil

in

fuel

2%

(50:

1)

Self-mixing

two-stroke

oil

6

6

7

8

Type 'A' automatic transmission

fluid

(ATF)

or

SAE 1

OW/30

motor

oil

200

cc (0.35

Imp

Pint)

A one-piece

welded

steel exhaust

system

is

fitted,

and

this

incorporates a detachable baffle

to

allow

the

removal

of

carbon

accumulations.

2 Fuel

tank

end

tap

cleaning

1

As

has been mentioned,

the

fuel

tank

ls

an

integral

part

of

the

frame. and thus

cannot

be removed

for

cleaning.

If

it

Is

necessary

to

flush the tank. as a result

of

contaminated

fuel

for

example.

proceed

as

follows.
2 Set the

fuel

tap

lever

to

the

'Off

position

. Remove

the

banjo

union

bolt

which secures

the

fuel

pipe

to

the

carburettor.

Obtain a sealable

metal container

of

at

least

1 gallon capacity, place

the

end

of

the

fuel

pipe in It.

turn

the fuel

tap

on

and

allow

the

tank

to

drain

completely

Store the fuel

in

a safe place,

away

from

any

poss

ible

fire

risk

. ·

3 Slacken the gland

nut.which

retains

the

fuel

tap

to

the

tank

outlet

stub

and

llh

it

away

. Examine

t'-'

gauze

strainer

on

the

tap

and

remo

any

dirt

which

may

have

accumulated.

ve

60

end lubrication

Chepter 2 Fuel system

4

Tempcx~

plug

the

tank

outJe

using

a cork. Pour

In

aboUt

one

pm

of

dean

fuel

refit

the

cap

and rock

the

machine

from

side

to

aide

to

flush

the

tan1t.

Remove

the

plug.

catching

the

fuel In a suitable

bowl. Check

'°"

signs of

dirt

or

water

and

if

these

are present

reP8

8

~

the

oPeratiOn u

the

merging

f

dean.

If

the

orig

nal tan

contents

are

to

be

reused.

do

so

onty

If

you

are sure

that

no

contamlnants

rema

5

Refit

the

fue

tap

by

ng

I.he nmtOV•I t;equence Reconnect

the

fuel

pipe

and

the

tan

Tum

t fuel tap

on

and chedt carefully

for

I a

3

Fuel

pipe

•

.umination

and

renewal

1

The

fuel

pipe

I

mado

of

synthetic

rubber

tubing

and Is

se~ured

~o

the

union

at

each

end

by

cnmped

femJ!es

In

time

, the pipe

~II

det

riorate

and

It

shOuld

be

checked

periodically

for

signs

of

cracking

or

hardening

2

If

r ncwal ls n c saary.

dra

in the fuel

tank

as

described

in

Section

2.

and

remove

th

tap

and

pipe

complete.

Most

motorcycle dealers

wm

be

able

to

mak

up a new

pipe and

crimp

It in place

on

the

fittings

Failing this. carefully

file

or

hacksaw

through the ferrules

to

remove

them

and

fit

a si

milar

length

of

synthetic

rubber

or

fuel-resistant plastic

tubing. The

ends

can

be

aecured safely,

though

less neatly, using

wonn-dnve

hose

clips

.

3 Refit

the tap

and

hose

union. using

new

fibre washers

on

the

latter

as required . Check carefully

for

leaks. NOTE:

On

no

account should

natural

rubber

tubing

be

used

to

replace the fuel pipe. The rubber

will

be

dissolved

by

the fuel and the resulting sticky

gum

will

block the

carburettor

.

4

Carburettor

removal

and

refitting

Tum

the

fuel

tap

to

the '

Off

position and disconnect the fuel pipe

union

at

the

carburettor

end. The carburettor

is

retained

by

a single

clamp

bolt

to

the

intake flange. the

latter

being secured

to

the

cylinder

barrel

by

two

bolts. The

carburettor

can

be

removed

with

or

without

the

flange

.

2

Once

released

from

the engine, manoeuvre the carburettor clear

of

the

rubber

adaptor. Unscrew

the knurled top and

withdraw

the

throttle

valve

assembly

from

the

carburettor

body.

3

Installation

is a straightforward

reversal

of

the removal sequence.

If

the

flange

was

removed

, check and

if

necessary

renew

, the gasket.

5

Carburettor: dismantling,

examination

and

reassembly

Slacken

and

remove

the

two

screws

which

retain the float

bowl

top

and

lift

it

away.

Invert

the

carburettor and

tip

out

the

float

assembly.

Remove

the

hexagon-headed main

jet

holder

from

the side

of

the

carburettor

body, then

unscrew

the main

jet

from

the

holder.

2

If

attention

to

the

throttle

valve

is

necessary, compress the return

spring

and disengage the

throttle

cable. Prise

out

the gauze

filter

element

and

place

it

to

one side.

3 Check

that

the

carburettor

body

is

clean, washing

it

out

with

clean

petrol

to

remove

any

sediment. Examine the main

jet

for

obstructions.

These

can

be

removed

by

blowing

the

jet

through

with

compressed air.

If

the

blockage

is

stubborn, clear

it

using a nylon bristle.

Note

that

wire

must

never

be

used

for

this

purpose because

the

internal bore

of

the

jet

will

be

damaged.

4 Shake

the

float

to

check

for

leakage.

If

fuel can be heard inside

the

float,

it

must

be

renewed. Examine

the

condition

of

the

float

needle

and seating.

If

scoring

or

an obvious groove can be seen

renew

the

float

and

the

needle seating. '

5

After a high

mileage has been covered, the

throttle

valve (slid )

may

wear. This

will

~ften

allow

~ir

leakage

between

it

and

t:e

carburettor

body,

making

carburat1on erratic and unreliable s h

damage

will

be

evident as a polished area

on

the

valve and

if.

uc

·

1·

k'

d h h severe

will

cause a c

1c

mg

soun

w en t e engine is running.

If

renewal

of

the

valve

does

not

cure

the problem.

it

may

be necessary

to

renew

the

carburettor

body.

6 Reassemble

the

carburettor

by

reversing the dism ti'

· b I t I

1·

an

mg

sequence.

ensuring a sou

e c ean mess. Take care

not

to

overt·

ht

· h rb

bod

· . .

1g

en

any

of

the

screws.

t e ca

urettor

y

1s

cast m

brittle

zinc alloy and

is

easily

damaged.

5. 1 b

Lift

out

the

float

assembly

and

check

for

leakage

S,IC

Rfl!IOVI

lhlll

rm1ln

jot holdor

from

lh11

aldn

nf

th

c

11rhur1

ttor

I

Cl

1 d M In I I

i:;M

hi! un crowed from holder for c

lHnlng

~18

Fig.

2.

1

Carburettor

and

air

filter

1

Cnrb11Tt1t1<1r

2

Air

filter

ttlt1mt1m

3 Float

bowl

gnslt11t

4 flo11t

5 Flottt

bowl

top

6

Screw

- 2

off

7

Fuol

filtfr

8

Fuel

plpo

union

9 8

tt11/o

union bolt

1 O

Cnrburtmor

1<.nvrlt1d

top

11 Rttturn

spring

1 2

Throttle

vttlvs

13

lntol<.8

flttnge

14

lntttktt

flttnge

gasket

15

Clnmp

screw

16

Main

jet

holder

1 7

Main

jot

18

lnrttl<B st'lBncttr

19

Fiiter

adaptor

20

Pipe

21 Bolt - 2

off

22

Washer

- 2

off

........

1

Alf

fitter. retno¥al

end

CIMnlng

1

TI,.

wl1'11

gauie

filter elem

nt

can be r moved for cleaning after

the

rubber

edaptor

betw

n th carburettor nd

th

intake llencer hos

been diaplac.cf Uft

out

th

el ment and

wa

h it thoroughly

in

clean

petrol

to

1'9rn<>Y9

•cC\Jmulated road d rt, then allow It

to

dry. Soak the

•l•mtnt

In clean engine oll then r

ftt

It

2 On

no

account run the engine

wlth

the filter

or

adaptor rubber

missing

Anv

den

drawn Into the engine will cause weer and scoring,

reducing the lite

of

the engine .

It

should elso be noted that the

carburatlon

hu

been set

to

function effectively with the filter in place.

If

11

la

omitted

the m1•ture will be weakened and there will

be

some

risk

of

engine seizure.

Fig

. 2.2 Exhaust system

1 Exhaust pipe

2 Screw

3

Baff

le

tube

4 Packing
5

Nut

-2

off

6 Spring washer - 2

off

7 Washer - 2

off

8 Bolt

9 Gasket

1

The

uheul1

lyttem

11

I

~

ftnllhed

In

chromium plate

Ind

In~

atrok• 1ngln11 lnv1rl1bly

Produ~

·'"°"

af

gaHI

than would 1 comp1r1bl1

four~

c:ondenH

In

th•

11e

h1u1t 1v1t1m,

btoom1ng

1

1

period

of

time

.

2

Thi

b1ff11 ln1ert

11

1tcur1d

by

1

•Ingle

removed vii 1 1m1ll hole neer

tht

rHr

of

the

removed

grHp

the

horl1ont1I

bar

acroq

tht

pllere then

twist

end

pull

the

baffle

out

Of

the

done regularly, there shou

ld

be

no

•trloua

di

befflo, though In

11

badly

neglected 1v1t1m

It

COUid

even impossible

to

shift.

3 Remove tho 11ccumulotod carbon dePOllta

i...

brushing

insuring

th11t

the

baffle holea and •Iota 1"'

4 In cases

where the system

has

become

btdty"

carbon, baffle removal

may

prove lmpo11Jble Ind

approach

will

be necessary.

It

wlll

first be nec

1111

1

system from the

mochlno

by

roleaslng the two

t'#.~

to

bolts and tho silencer rear

mounting.

The silencer

end:*

securely

with

11

Jorge

cork

or a wooden

bung medt

to':

5 The method used

to

removo

car

bon deposits

from

system

Is

to

dissolve thorn

by

using a chemical

aolutJon

dissolved In

wator

Is

the

solution

most

frequently

u1ec1'

11

l

effective and rolotlvoly cheap. The mixture

uaed

la

1

l1tlo

If

caustic soda

to

a gallon

of

fresh

water.

This is the

atron8'1t

llkely

to

bo required.

Note

whilst

mixing

the solution

thit

the

soda should

bo

added

to

the

water

gradually, whllat

ltlrrlng.

pour the

water

Into a container

of

caus

tic

soda power

or

will

cause a v!olent reaction

to

take place which

Wiil

rtluft

Ill

danger

to

one s person.

Chapter 3

Ignition

system

S~tions

Ignition system

I

2

3

4

Type

--·--····--······---·····-······---····-·············---········

Ignition

timing

-·······

···-···--·-········-···-······················-··-············

Contact breaker gap -·······-·····-····-·········--·····-··········-·-·············-

Spark

plug

Make·

-····-········--··--···············-······

·····

..

·······································

S

ize

-····-·-··-····-···-············

..

···

······-·······································

TVJ>8

-··-··-····-·-···········································································-··

Electrode gap ····-···-.. -·-············································

···

·····-·····················

1 General description

. The

igniti~n

. system is of the contact breaker type and is

lrlCOrpora~~

w~th~n

the flywheel generator assembly (flywheel ma

neto).

lgnit1.on

timing is determined

by

the point

at

which

the

conta~

brea~er

points

~~parate.

and the

firing

point may be adjusted b

altenng the

P<>Sltion

of the generator stator. Y

.

The

system requires little maintenance other than period" .

tion and adjustment of the contact

break~r

.

IC

mspec-

plug

maintenance.

It

should be not d h P?ints. and regular spark

developing

in

the system most

of

thee t

at

in

the event

of

a fault

use of a test

rig.

This

is

~nlikely

to be

~~:l~~~ent

tests

will

require

the

therefore consult a Tomos dealer Roufn h e

~o

owners,

who

should

be

performed

at

home and are

descri~~

~

ech

s and

a~justments

can

in

t e following text.

2

Contact

breaker

gap:

checkj .

ng

and

ad1ustment

1 Place the machine on its stand

plug. Remove the left-hand

shroud

and;emove the

HT

lead and sparit

ga2

lnRaccess

to the

ftvwhee1

QeneratC:.n

the left-hand outer cover

to

otate the

A.-

• ..1..

88

1 •

The

"'"'"

rotor

by

hand unfl the

contact breaker assembly can

be

•

1

contacts are fully

0

the rotor.

Examine

the contact

faces.

vilfew~

through

the

WinA--~!'·

further using a small screwd . required they .

""""VS

in

be renewed

bei

nver.

If

burnt

or

P1tt.

can

be

opened

good

condition.~

~rther.

See

Sec:!

t~e,:nta~

must

3

With

the

contacts

fully

ct

gap. details.

If

in

the

gap

..

outside

the

open,

check

the gap .

adJustment

will

be

range

0.35 - 0.45

"""~

feeler

gauges_

If

l'9CIUinld.

•

014

-

o.01e

inl

Flywheel

generator.

incon><>rati

ng

•

gnition

coil and Ulllllll

24° 1.

8 -

2.0

mm

(0.071

- 0.

079

· before

n>p

demi

0.35 -0.45

mm

(0.01

4 -

0.01

8

in)

Bosna

14

mm

F

75

0.5

mm

(0.0

20

in)

Chamoion

l

86

G

B6HS

4 S acKen slightly

the

cheese-h

eaded

screw which

contact

to

the

stator. Us'ng

the

notch

provided,

move

...

unt

il

the

required

gap

is

obtained.

Ttghten

the

screw

..r

gap, repeating

the

ooeration

if

necessary

.

If

it

prOll9S

obtain

the

correct

setting

it

·s e y

that

the fibre heel

fl

contact

has

worn

down.

If

tti s is

the

case reoew die

assemb

ly.

3

Contact

breaker

assembly

:

renewal

If

the

contact

faces are badly

pitted

or

the

...,.

must

be

renewed.

It

should

be

noted

that • .,.....

Number

700.334

will

be

required -

it

is

not

adu.

**

•

puller.

2 Holding

the

rotor

with

a

strap

wrenc:ti

..,....

..

slacken

and

remove

the

rotor

nut

aod

washs.

$c:IWlf

..

thread

provided,

then

tighten

the

centre bolt

10

*-

taper.

If

it

does

not

come

off

easily.

try

tapping

.,.

it free.

3 Noting carefully

the

arrangement at

wazhllS

11

disconnect

the

contact breaker lead.

then

,.._

..

by

pulling

it

off

its

pivot.

Remove

the

screw

_......

contact

and lift

it

away.

4

Frt

the

new

contact

set

in

the...,..

....

do

not

tighten

the

fixed

contact

9Cl1IW

fulr

......

contact

spring

and

the

contact

....._

....

•

5 Apply a

trace

at grease

to

1he

...

d

1119

heel.

Refit

and

secwe

the

l'OlUr,

.......

_.

...

ovar

the

cam

inside

the

rotor.

s.

1he

C.-.

in

Section

2.

jiP

3

1 2

~

®@

15

4

(}]

0.35-0.45mm

r-

~

Fig.

3.2

Contact

breaker

gap

measurement

Fig. 3.1

Ignition

system

components

1

Nut
2 Washar
3

locating

pin
4 Condenser
5 Flywheel

rotor

6

Stator

7 Washer - 5

off

8

lock

washer - 3

off

9

Screw

- 3

off

10

Screw

11 Ignition

coil

12

Spring washer - 5

off

13

Screw

- 2

off

14

Suppressor cap

15

lighting

coil

16

Screw

- 2

off

17

Contact breaker assemb

ly

18

HT

lead

~

..............

IJ'lll

.....

·-

'

,..

.__

......

lfmuld

be

cMCUd

......... .,., the

~

....

-·

._ -

to

IUtped

the

~ecy

.....

II

r9lftOWd

01

I._.•

eftY

•-·

....., ....,..

ne

timing

~

9ffecl

the

.,,,..,

........

N

.......

lfwclcur'IM

cMn'leQe

left

11M4u1ted

Not•

,.,,..,

end

In

eatrWM

~

INY

C**

c:heeked

nd

reMt.

...

it

11

llTCM

'*''

Chet

the

cont.ct

breal•

VIP

19

a

I

n«tlfl')

t.b'9

IM

dmiing

~

rt

pfug

ad41ptor

will

be

2

To

cl-*

the

timing

•dial

v-uge

1

IP8 dealef or

by

mail

nee1111

r

8nd

m.t

'*1

be

Obtained~

•

Tomost

-•e

.va11

In

the

order

from

one

of

the

edll'enlMn

In

tn•

mo

or

..

,...

....-

abl9nee

Of

this

equipment the mach

ne

should

be

11ken

to

11

Torno•

....,

for cheC:llng

Ind

l14ustment

3 Al90

1'9QUlred

fa

IOm9

method

of

checking the exact point 11

wh

ich

the

ciontactl

eep1rate. A

muh

meter t on the reslstanee scale

may

be

UMd

If avellabfe but

fl

mg

th11

1 simple torch

bait

rv

and bulb

arrangement

may

be

used

The

accompanymg

hne

drawing

shows the

rwo

atranoem-ntt

~

Remove

the spart

plug

and flt the adaptor and the dial gauge

to

me

pfug thread Est1bl t exact pasltlon

of

top d ad centre (

TOCI

,

tum

ng

the

cr1nklhlh

backwards and forward

by

hand Set tho dial

gauge acal• to zero

11

TDC

5

Con"9C1

the

multimeter

or

battery/bulb arrangement across the

contact breaker points. connecting one

probe load

to

the contact

breaker terminal and the remaini

ng

probe lead

to

earth.

6 Rotate the rotor clockwise untll the contacts just touch. This

will

be

Indicated

by

the bulb lighting

or

the multimeter indicating conti·

nulty Note that

It

ls

lmpanant that

th•

rotor must approach the firing

point In

1 clockwis direction only;

if

necessary, turn the rotor back

an

Inch

or

two

and

start

again.

7 Note the reading shown on the dial gauge.

If

the ignition is set

correctly, the

firing point should occur when the piston is 1.8 2.0 mm

(0 071 -

0.079

In) BTDC, as indicated

by

the dual gauge.

If

the

Ignition

11

too advanced, the stator should be turned in the direction

indicated by the arrow embossed on the rotor, whilst

if

retarded

it

must

be

moved In the opposite direction.

8 Slacken the stator retaining screws

by

one

or

two

turns and move

it

by

the necessary amount, retighten the screws and check the timing

as described above.

If

necessary, readjust the timing until

it

is within

fimlts.

0

©

Fig.

3.3

Simple

testing arrangements

to

determine

contact

breaker separation

A Multimeter

B Bulb

C Battery

D Positive probe

E Negative probe

5

Checking

the

ignition

coil

1 A full test

of

the coil performance r .

test

rig (SEM-MA

2)

available

at

Tom:aq~ire~

the use

of

a specialised

warrant purchase

for

home use.

If

the

qulc:a

~rs

kbut

t?O

expensive

to

to

confirm the condition

of

the coil

it

sho

1

~

beec

outlined

below

fails

dealer. ' u checked

by

a Tomos

2 Remove the spark plug, connect It

to

the HT

thet the

plug

body

i.

In contact

with

a sound

rth

lead and lodge

It

so

Operet.

the

ldckstart

and note the appearan:.•

of

,rlnt

on the engine.

electrode& e

'P•rk

at

the plug

3

If

the

tyatem

II

operating normally

1

f

evident.

If

a weak or yellowleh spark la

~ld=t

blue 8P8rk should

be

If

thla

faffs

to

rnolve the

problem

and the

con111;:

~ew

'Plrk

plug •

..... aker

polma

are

•t

correctly

It

It

likely

that

the

coll

or

lht

this confirmed

bV e full

tnt

befOf'9

conclliea

..

e

Checking

the

condenHr

t

The

condenser Is located

on

the

99nerator

to

prevent arcing

acrou

th•

contact brHker

-

If

the engine is

difficult

to

start

or

ml1flring

occu,.~

condenser Is

at

fault.

Arcing

ecro1a the

l>OI

blackened

or

burnt

poin

t fac&1.

nta

2

If

the

co~de.nser

Is suspected

of

being faulty It

by

1he

subst1tut1on

of a new

compo

nent, there

~

available from the manufacturer.

-""IJ

no

3 Follow

the

instructlon1 In Chapter 1

leeti

generator

rotor

removal.

With

the sta

tor

pie.ta

811

on

I

can be identified as the cylindrical component

0

~

t111

of

the plate.

Tak•

note

of

the three wire poiltlon

~

removal as a guide

to

refitting.

1

_,.,,.

7

Spark

plug: checking

and

reeettlng

the

gap

1 The Tomos mopeds ere

fitted

with

a Bonsa F

76

standard equipment.

It

is unlikely that this brand

of

pl

'P11t

in the

UK

, so one

of

the alternative fitments ugWflbt

Specifications should be used as o replacement.

lhown

In

2 A

new

plug

of

the correct grade and type should

be

Cl

machine

Although

plug

fouling is

not

a common

problem"':•

useful

to

have a sound replacement to hand should

the

~

II

3 It is

not

usually

worth

bothering

to

clean

used

spark

pl

...

plugs are relatively Inexpensive and eliminate the

Poellbil

l'llf,

flllr

internal

fa~lt

.

If

the

plug

is

to

be reused,

do

so

only If It

le::~

worn

or

011

contaminated. Remove any carbon

deposits

by

...,

~craping

of

the electrodes, taking care

not

to

damage

tht

C::

insulator nose.

4

So~e

garag~s

offer

a.n

~bra.sive

cleaning service,

and

homt

M

are available

which

do a s1m1lar

JOb.

If

the plug is ba&icallylOUlldllla.

methods are

quite acc

eptable,

but

make sure that no

traces

of..,,.

remain

after

cleaning.

5 The plug electrodes

should

have a gap

of

0.5

mm

(0.020

lit

adjustment is necessary, benn

the

outer, earth electrode

only

.

OI•

account

try

to

bend

the centre electrode: this will

almOlt...,,

result in the ceramic

insulator

being damaged.

6

When

refitting

the

plug

, apply a trace

of

graphite

gre•

ID•

threads

to

ease future removal. Fit the plug hand-tight

at

flrll.

•

secure it, using a

proper

plug

spanner. Turn

it

by no

more

than!•

It

is necessary

only

to

seat the plug firmly; there

Is

no

pallll

overtightening it.

7

If

the

plug

threads

in

the

cylinder head have

been

damaged!njl

past,

th~y

can be reclaimed

by

fitting

a Helicoil

insert.

Thll

11

•

inexpensive service offered

by

most

motorcycle

dealers

and

wllllll

avoid the need

to

renew

the

cylinder head.

, .

. ,

SI>""

plug

maintenance:

Checking

plug

gap

with

feeler gauges

Spark plug

conditions: A brown,

tan

or grey firing

end

is

indicative

of

correct

engine

running

conditions

and

the

selection

of

the appropriate

heat

rating

plug

Black

sooty deposits

indicate

an

over-rich

fuel/air

mixture.

or

a

malfunctioning ignition

system.

If

no

improvement

is

obtained,

try one grade

hotter

plug

A bliste d . · d. cates

over·

adva re. white

insulator

or

melted

electrode

m .

1

lfco~Ced.ignition

timing

or a malfunctioning

cooling

:,St~i;:i

·

rection does

not

prove

effective,

try a colder

gra

P g

Altering

the

plug gap. Note use

of

correct

tool

,

White deposits have

accumulated

from

excessive

amounts

of

oil

in

the

combustion

chamber

or

through

the

use

of

low

quality

oil. Remove deposits

or a hot

spot

may

form

Wet, oily carbon deposits

form

an

electrical

leakage

path

along

the

insulator nose, resulting

in

a misfire.

The

cause

may

be

a

badly

worn

engine

or a malfunctioning

ignition

system

A worn

spark

plug

not

only

wastes fuel

but

also

overloads

the

whole

igni!i<?~

system

because t_he increased

gap

requires

higher

voltage

to

m1t1ate

the

spark.

This

condition

can

also

affect

·

pollution

air

1

S.

GtMM

the piug threads

th9n

ln1t11l

1t

finger

tight

only

•

chapter

4

Frame and suspension

cjeSCfiption

...................

........ · ······ ····· · · ··

·· · ···

··

····

· · ············ ··· ··········

~

fl)IU:

removel

end o.verhaul_

···

···········

···

···················

·············

······

fft."'I

,

held

assembly

:

d1~manthng

and overhaul ........................ .

~

heed beerings:

ed1ust~ent

......

...

.......................................... .

~

,..mination

and renovation ......

...

........

.....................

........

...... .

f!llTll

1

2

3

4
5

Type

.......

.....

................

..............................................................

....

............. .

f1ont

llJIPMSIOn

Type

•......••.•..•..••...•

.•.•

.•.•.•••.••.•.

...•...................................••..•..•.....•

...

..•...•...•.

Travel-·····

·········

······························

···

·························································

R•

suspension

Type

.......................•

..........•.

..•

.....................................................................

T

n1vel ................

.............

..........................................................................

..

.

1

General

description

The

Tomos

mopeds employ a

welded

semi-monocoque frame

of

~

design

,

the

engine being carried

below

the

main frame membe

r.

!he

main

frame

section is fabricated

from

steel pressings and

flCO!pora

tes

the

fue

l tank in

its

front

section.

F

iont

suspension

is by simple. undamped coil-spring telescopic

b\s.

Rear

suspension

is provided in

the

form

of

a swinging arm

llingemen

t supparted

on

twin

coil-spring rear suspension units.

IOltJ~

e

are

various

types

of

seat fitted

to

the

Tomos models. those

bw

111

~

UK

having

either a sprung cantilever saddle

or

a larger and

~

~ngle ~at

un

it. All models are equipped

with

a luggage

ra.ck

.

CWithe

orn

painted

pressed steel

or

chrome-plated tubing , depending

m

ode

l.

;---

F~~:fu~11ta-

-

----------------------~~~~~---

:--.-..::.:

· removal and overhaul

1

11

is

Unlik

. .

'-ljess

they

e

ly

that

1t

will be necessary

to

disturb the front forks

~Ssi

ve1y

have

been

damaged in an accident

or

have become

P

la

ce

th~orn.

In. each case,

the

affected parts are easily renewed.

°'·g

round.

T

rnachin~

on its stand and raise

the

fr~nt

wh~el

cl~ar

of

~hts

to th

he easiest

way

to

accomplish this

1s

to

tie

suit~ble

~iScao

n

e

luggage

rack

or

to

lash

down

the

rear

of

the machine.

llit

!!Wing :: the

speedometer drive cable

st

the

whee~

by

~

oi>e

rati

ng

e knurled retaining ring. Free

the

front

brake cable

ro;

• ~ adiuste

arrn

by

releasing

the

nut

and anchor piste. Unscrew t e

!Ian

~lllave

~

h!"~

l<>dge

the cable clear

of

the

wheel. dgusrd

lie

10

O

fll

th

e e ront

Whe

el spindle nuts. disengage the mu leer

of

5

~~

·

Placin nd_s

of

the wheel spindle and

lower

the

wheel c

~

"'°"e th2 it

to

one side. . tsin the

,.......

~

four nuts. bolts and washers

whi

ch re

Swinging erm essembty:

e111min1tion

, remover

ind

overheul ....... 6

Centre stend: e•emination .

........

....

........................................................ 1

Speedometer heed: removel end replecement

.................................. 8

Speedometer drive cable: examination end renewel

.......

................ 9

Cleaning the mechine

...........

.................................................................. 1 0

Welded tubular steel. incorporating fuel tank

Undamped coil-sprung telescopic forks

60

mm (2.4 inl

Swinging arm with coil-spring suspension

units

40

mm

(1

.6 inl

mudguard to the lower legs. Manoeuvre

the

mudguard clear

of

the

forks. taking care not

to

scratch the painted finish.

6 Remove the four Allen bolts

wh

ich retain

the

handlebar

clamp

halves. Remove the clamp halves and

lift

the

handlebar assembly clear

of

the top yoke. resting

it

against the frame and using rag

to

protect
the paintwork.
7 Remove the large plated esp

nut

from the

top

of

the

steering stem.

followed by its plain washer. Remove

the

two

small cap

nuts

above

the

fork legs, then

lift

away the

top

yoke.

8 Slacken and remove the

two

fork spring anchor

nuts

. Grasp each

leg in turn and pull

it

downwards. The

lower

leg, spring assembly

and
dust seals are removed as an assembly.
g Check for free play

betw

een

the

lower

legs and

the

upper

tubes.

No

precise tolerances are available.

but

wear

can be assessed qui

te

easily

by

comparing movement in a fore-and-aft sense

with

side

to

side play.

If

renewal

of

the

lower

legs fails

to

cure

the

problem,

it

may

be

necessary

to ren

ew the upper tube/

lower

yoke assembly.

1 O If checking

for

accident damage, renew

the

lower

legs as a matt

er

of

course

if

they have been bent. This can be checked

by

rolling

them

on a flat surface.

If

the upper tubes have also sustained damage, these

too

should be renewed as described

in

Section 3.

11 Whilst minor damage can often be straightened in a press .

this
calls for professional help.

It

should be remembered

that

straightening

the

forks does not guarantee

that

the forks have

not

been

overstressed. The risk

of

subsequent failure does

not

normally

warrant

attempts

st

repair.

12

When reassembling the for

ks,

make sure

that

the

spri

ng

units

are

screwed firmly into the lower legs. Grease the

lower

legs and springs

to

ensure smooth operation and the absence

of

harmless

but

alarming

no

ises from the forks.

13

When fitting the front wheel. ensure

that

the torque

arm

on

the

brake backplate eng.sges over the

loc~ting

pin

on

the

fork

leg, and

that

the

speedometer drive dog engages m the hole

in

the

hub. Spring

the

mudguard stays into plac

e.

then

fit

and tighten the

wheel

spindle

nuts

.

2 5 R

move

the

four r

claar

of

th

fork

2 7 Remove the

two

small cap nuts (A) and steering stem

nut (Bl

then

remove

top

yoke

2.12

Check

that

springs are securely screwed

into

lower

legs

2

6 Release the c

lamp

halves and

lift

handlebar assembly

cl

.

~~

steering head

2.8

Release the

two

fork

spring

anchor

nuts

to

free fork

legs

from

the

top

tubes

3

Steering

head

assembly:

dismantling

and

overhaul

1

To

gain access

to

the

steering head assembly.

it

will

fi:U~

necessary

to

dismantle the

forks

as described in Section

2.

It

"th

the

be noted

that

whilst

it

is

possible

to

carry

out

the

o~e!haul

~e

to

forks in position,

it

is easier

if

they

are removed

and

1t

is

advi

check

the

fork co

mponents

at

the

same time. blytotht

2 Remove the

two

bolts

which

secure the headlamp

asse~

vlng

first

upper

tubes

. Lift

it

clear and unplug the

wiring

connectors. ~ duni.

made a

simple

sketch

to

show

the correct connectio

reassembly.

tingbCJll

3 Disconnect the horn leads then release the single

mounptug

dill

and

lift

it

away. Lift

the

in~trument

panel clear.

and

b':; tofltll.

speedometer

lamp

and

unscrew

the speedometer drive

ca

tht-

4 The steering head assembly can

now

be removed afte:.ci thlt

1111

steer~ng

head

nut

has been unscrewed.

It

should be

"°1s~

steering head bearing balls

will

drop

free as

the

assembly~

It

and some provision

must

be made

to

catch them.

It

lathe--

spread some clean

cloth

below

the

headstock

to

prevent

bouncing

on

a hard surface.

~

5 Examine the steering head balls,

cups

and cones for

.hOul'

or

damage. The

working

surfaces

of

the

cups and cones

11

from

corrosion

or

indenting. Note

that

even

If

lndentlnl

often enough

to

cause vague

or

'notchy'

steering. the"'

6 The bearing cups can

be

removed

by

driving

Chapter 4

Fra--

··-

•nd~

e1

8

®-32

Efr-33

~10

,-11

~14

~12

f-3

30

Hth482..

h

eadst

!QcL OCk

Usin

· a large

7

•et

as

ad

.9 a long

drift

. Tap

the

new

cups

home

using

di

lhe

uppenft

and ensuring

that

they

enter

the

bore

squa~ely

.

head

fit

S!nantli

ng

a~

~ne

will

have been

lifted

away

during

.

st:e;~~~Y

tight

u,~

the

stee

. is thus easily

renewed

. The

lower

cone .1s

ff

the stem

"'ot

a

Pair

~ng

stem.

It

should

be

possible

to

work

it

o mbly

to

a

~Cle

deal

screwdrivers.

If

this

fails

, take the

ass~

cone can

'-.....

er

to

have

the

old

cone

drawn

off

. The ne

0

Fig. 4.1 Front forks end

atHrlng

heed

euembly

1

Lower

yoke
2 Top yoke
3

Allen

bolt

- 4

off

4 Fork cap

nut

- 2

off

5 Spring

anchor

nut

- 2

off

6 Spring seat - 4

off

7 Spring - 2

off

8 Right-

hand

lower

leg

9

Leh-hand

lower

leg

10

Sleeve

11

Bolt-4

off

12

Nut-8off

13

8olt-4

off

14

Spring washer - 8

off

15

Front

mudguard

16

Top

mudguard

brace

17

Bottom

mudguard

brace

18

Bearing cone - 2

off

19

Bearings

20

Lower

bearing

cup

21

Upper bearing

cup

22

Dust

cover

23

Adjusting

nut

24

Washer

25

Steering

stem

nut

26

Plastic insert spacer

27

Damper

insert spacer

28

Grommet - 2

off

29

Steering

lock

30

Lower

handlebar

clamp

- 2

off

31

Bolt

- 2

off

32

Spring washer - 2

off

33

Nut

- 2

off

34

Upper handlebar clamp - 2

off

be

fitted using a tubular

drift

.

8 When reassembling the steering head, apply grease

to

the

cups

and cones

to

stick the bearing balls

in

place.

Note

that

the

balls are

0.5

mm

in diameter and

that

21 are

fitted

to

each race.

9 The

slott~

~djuster

nut

sho~ld

be set so

th~t

free

play

is

just

taken

up. Note

that

1t

1s

easy

to

overt1ghten the bearings, placing excessive

pressure on the balls and races and making

the

steering

unduly

heavy

.

82

Chapter 4 Frame and suspension

3.2

Remove headlamp from brackets and unplug leads

3.4

Note

that

bearing balls (arrowed)

will

drop free as the slotted

adjuster

nut

is unscrewed

4.5a

Slacken

or

remove

the

steering head cap

nut

(arrowed)

3.3

Unscrew knurled ring

to

free speedometer cable

4

Steering

head

bearings

adjustment

1 The

adjustment

of

the

steering head bearings should

be

checked

whenever

they

have been

disturbed

or

if

the steering

feels

vague

or
heavy.
2

Place the

machine

on

its

stand

and raise the front w

heel

clear

of

the ground. The easiest

way

to

accomplish

this is to tie

suitable

weights

to

the luggage rack

or

to

lash

down

the rear

of

the

machine.

3 Check

for

excessive free

play

by

pushing and pulling

on

the

handlebar. If any

movement

can be felt, the bearings

shou

ld

be

adjusted. Check also

that

the

bearings are not too ti

ght. The

handlebars sho u

ld

turn

easily

from

lock

to

lock, with

no

sign

of
stiffness.

4

Note

that

if

the

steering feels

'notchy' when the

handlebars

are

turned,

it

is likely

that

the bearings

have

become inden

ted.

If this is

suspected,

dismantle

and

check

the bearings

for

wear

as

described

in
Section

3.

5

If

adjustment is required,

start

by

slackening the

large

cap

nut

at

the

top

of

the steering stem.

Adjustment

is

made by turning

the

slotted

adjuster

nut

below

the

top

yoke

in

the required direction. .

6

Set the adjuster

nut

so

that

free pl

ay

is

just

taken

up.

Note

that

rt

is easy

to

overtighten

the

bearings, placing excessive

pressure

on

the

balls and races and making

the

steering unduly heavy.

4.

5b

Adjust

bearings using a C-spanner

(top

yoke

removed

tordlfll"

a.....,

4

,_Md

I

1$17111•

2

Mt.

..

llllllMI•

._

.......,

•

tan1'?

II*

ESP

~----::=·-.-.ion

end renovetion

......,

...

_.

...

._.......,..,.,...,~_.

~:

-~--

81

....

welded

........................

Udll•

···d

.. • ...

..

t

~

·kefV

to

require attention

uni

...

accident dem.ge

loints.

Mlnorclamlgecenbtrepalredbf

......

Gl'

.........

I

,,_.,

11

unll cases renewal

of

the

frame la

the

only

on

the

at.n

end

.,.....

of

the

c1em1ge.

1

111'_:..,ed.

In

'f.:~e

tram~

Is badly

out

of

alignment, Only •

few

3

Remember

that •

rmn.

which le

GUI

of

algiiment

• 0::

-..!;Y-,.inedY

the jigs and mandrels necessary for resetting handling

problems

end

~

evel'I

pomoee

IPMd

wotAalel

If

Hl'I

,._......--~ts

hav~

ed standard

of

accuracy. and even then there la alignment

i.

SUlpeeted

, • •

rnuh

of

en

accident.

It

wll

~

MC

1

aJ

.....

__:';

th8

requir ssing

to

what

extent the frame may have been

to

strip the machine completely

IO

that

the

fr8fM

oen

be

c:necUd.

.,,..

..

fi,een•

of

•

118

If

necessary, reoewed

~~·~

:__----------------~:::::.::.:::::.:::.

______________

~

16

27

'-

~

29

'ft@

28

Fig.

4.2

frern•

end

fftdnllS

1 Frame

2

Swinging

arm

bush

- 2

off

3 Fuel cap
4

Fuel

tap
6 Ferrel
6

Fuel

pipe

7

cable

channsl

8

Ssat

9

Bolt

10

Spacer-2

off

11

Bolt

12 Washer - 2

off

13

Nut

- 2

off

14

Rear

cerrier

16

Trim

16

Rear

mudguard

17

Nut-6 off

18

Washer - 6

off

19

Screw-6 off

20

Right-hand

engine

shroud

21

Left-hand

engine

shroud

22

Rubber

mat

23

Rubber

mat

24

Screw

- 4

off

26

Washer

- 4

off

26

Nut-4

off

27

Spring

washer-4

off

28

Screw-2

off

29

Washer - 4

off

30

Centre

stand

31

Spring

retainer

32

Return

spring

33

Nut

34

Bolt

36

Screw

- 2

off

36

Washer

- 2

off

Chllpter

4

frame

and

suspension

4

ff

it

..

nec:esurv

to

repair

the

tr.me

11y

~lding

it

must

be

remembenld

that

the

fuel

tank

is

incx>fpofeted

in

IL

In

view

of

the

risk

of

fire

Of

explosion

t!Ws

wort

5hou1d

be

sntrusted

to

en

e.apert

with

expenence

of

this

type

of

woB..

8

Swing

ing•""

eSMmbly. exemlnetion,

remove!

end

ovemaul

Aher • high

m leage

has

been

QOV8f8d,

It

ls

possible

that

the

aw1ng1ng

arm

assembty I

begin

to

show

signs

or

wear. Anv

such

free

play

teod1

to

develop

slowty

and the gradual deterioration can

often

go

unnoticed

by

the

owner. It

la good practice to check the

HMmbly

for

play

on

a regular

bam

and at least once e year.

2

With

the machine

on

ha

stand. grasp the enda

or

the

swinging arm

and

try

to

push

It

from

aide

to

side.

If

virtually

no

free

play

can

be

felt

the

pivot

can

be

considered serv1ceable. If, however, definite

wear

can

be

detected,

the

iwtnglng

arm should

be

removed for further investiga-

tion.

3 Place the machine

on

its

stand. Tum the rear wheel

until

the chain

jointing

I

nk

is accessible, pnSf!

off

the spring clip and separate the

chain. Run

It

off

the

sprockets and place It

to

one side.

4

Fr"

the

end

of

the rear brake inner cable from the operating arm.

then

unscrew

the

cable adju1ter and lodge the cable clear

or

the

wheel

Slacke~

fully

the rear wheel spindle nuts. push the wheel

forward unttl

1t

drops

clear

of

the

swinging arm and lift

it

away

.

6.3 Separate drive chain at the

joining

link and remove

it

Release

the

suspension

unit

lo"'."8r.

mounting

bolts.

5

Slacken

and

remove

the

swinging

arm

pivot

nut

bolt

oot

of

Its

bore.

If

the

bolt

proves

reluctant

to

Ind

Piii

...

refit

the

nut

by

two

or.

th~

ee

turns

and

tap

it

until

l"l'IC>v9, --

·----.

mo\le.

Support

the

swinging

arm

as

the

bolt

1

the

bolt...._

remove

it

and piece

it

to

one

side.

5

l>Ullect

delr-"

6 Push

out

the sleeve

which

is supported b th

bushes

in

the

frame

cross-tube

and

degrease

it

aJd

he

~

the

condition

of

the sleeve

and

bushes, renewln t •

bulhtl.

e\lident. The

amount

of

wear

can

be

checked by g fi

both

If

-..,

and

auempting

to

rock

it

in

the

bushes.

If

any discre

~Ing

the

felt. renewal is required em ble

Play

ceii

7

Note

that

the

swinging

arm bushes

will

be d

removal, so

do

not

attempt this until

new

bushes

ha

estroYed

du

Pass a long

drift

through

the

cross-tube

and drive

ve

been

obta

bush.

New

bushes shou

ld

be

drawn

into

position

o~t

the

arrangement as

shown

in the

accom

panying line

dr

us

~g

a

dr

8 Grease

the

bushes and sleeve

prior

to

reassem~7ing

.

swinging

arm

and

refit

the

pivot

bolt

and nut, tight v

.,

Offer

up

Ille

securely. Continue reassembly

by

reversing

the

disma

e~!ng

the

11

noting

that

c~ain

tension mu.st

be

set

correctly usin n

~~g

seq~ence

.

adjusters provided, and ensuring

that

the

wheel is

ke~t

1

?

ana11

Clin

swinging

arm. Mak?

s~re ~he

torque.

arm

of

the

rea~

1

~rned

in

the

engages correctly

with

its

pm.

The

chain is correctly te .

ake

plate

there is

20

mm

(f in)

up

and

down

movement.

nsioned

when

6.Sb

Lih

away

the

swinging

arm,

noting

guides

for

bnlke

CIJlJif

,.._..,.i.

tor tree play

between

the

sleeve and bushes

e&vi--

r

swinging

arm

z

PiVOt

bolt

3

Washer

r-~

-

,

Loc•

·washer

5

Nut

6

Sleeve

I

----

1

Suspension

unit - 2

off

s

Bolt-2

off

9

Washer

- 2

off

ro

Chainguard

II

Screw

12

Spring

washer

13

Washer

r4

Mounting

bracket

15

Footrest

bracket - 2

off

16

Footrest

rubber- 2

off

11

Boll-2

off

18

Spring

washer - 2

off

-

------

I

-----

-

~,

13

12

~

Fig.

4.3

Swinging arm

...

•mbly

•

_......,..1111an

C141114

,....._

!

Hrbtf

eb

Fig. 4 4

Orewbolt

arrangement

for

fitting

new

swinging

arm

bushes

7

Centre

stand: examination

1

Drawbolt

2 Washer

3

Bush

4

Bush

housing

1

The

machine

is

equipped

with

a pressed steel centre stand

retained

by

a

pivot

bolt

and

fitted

with

a spring

to

hold

it

in

the

re

tra

cted pos

ition

when

the machine is being ridden. No special

mainte

nance is required, but the pivot should be kept well lubricated

and

the return spring should be checked periodically. Although failure

is

not likely. the spring

must

be renewed

if

signs

of

wear

or

cracking

are

no

ted. Remember t

hat

the stand

will

drop onto the road

if

the

sp

ri

ng fail

s. a potentially dangerous situation that is best avoided.

7. 1 Lubricate

stand

pivots (arrowed) and check condition

of

the

return

spring

5 Tube

6 Washer

7

Nut

8 Sp

eedometer

head: removal

and

replacement

Re

1ease the headlamp

mounting

bolts

to

free the

i~

nacelle from the forks. Release

the

speedometer dri

ve

cable

llld

unplug the illumination

bulb

from

the

back

of

the instrument.

To

frll

the instrument head

from

the nacelle, unscrew the single nut

whidl

secures the support bracket.

2 In the event

of

speedometer malfun

ction always check

cat9'ulr

that

the cable is

not

the cause of the problem . If the instrument

iuelf

is at fault. there is

little

alternative to renewal, the

case

being

sealed

and repair impracticable.

9

Speedometer

drive

cable: examination

and

renewal

1 The speedome

ter dr

ive cable is retained

at

each end

by

a

~

nut

and may

be

remov

ed

after

these have been released.

Oieci

thll

the cable inn

er

turns smoothly. Any

jerkiness

or

tight

spots'"'..:::

responsible

for

erratic operat

ion

of

the speedometer.

TheSe

ant

Noll

caused

by

a kink in

the

cable and

will

necessitate its

renewaL

that

the inner cab le is

not

available separately.

10

Cleaning

the

machine

1

After

removing

all

surface

dirt

with

a

rag

or

IPO'lll9

---::

frequently

in

clean

water

, the machine should

be

8llowed

;,..

thoroughly. Application

of

car

polish

or

wax

to

the

cycle

I*"

...

a

good

finish. particularly

if

the machine has been negletlldflll'I

period.

.,,._

.

2 The plated parts

of

the

machine

should require onlJ I

_,.

damp

rag.

If

the

plated

parts

are

badly

corroded. •

m8Y

,,..

the

winter

when

the

roads

are

salted,

it

Is

per.able•-::.

proprietary

chrome cleaners.

These

often

have

en

aa,

...._

help

to

prevent

the

corrosion from

nH>CCU.m..

Chapter 4 Frame end suspension

87

f the engine

parts

are partiCt1lar1y oily,

use

a cleaning

compound

3

1

'Gunk'

or 'Jizer

'.

Apply

the

compound

whilst

the

parts are

dry

such

as

rk

it

in

with

a brush so

that

it

has

the

opportunity

to

penetrete

and

~o

of

grease

end

oil.

Finish

off

by

w11hing

down

liberally

with

th

8

1

m f

water. taking

care

that

it

does

not

enter

the

carburettor

or

the

plent'f'. 0 If

desired.

the

now

clean

aluminium

elloy

parts

can

be

electncsed

. further

by

using

1 special

polish

such

as

Solvol

Autosol

,

enhanc

which

will

fully restore their brilliance.

4

Wh

enever possible, the machine should be wiped

down

after

it

has

been used in the

wet

. so that

it

is

not

garaged under

damp

conditions which will promote rusting. Remember there is

little

c

ha~ce

of

water

entering the control cables and causi

ng

stiffness

of

operation

if

they

are lubri

cated regularly as re commended

in

the

Routine

Ma

intenance Section.

f.

t

r

t

Chapter 5 Wheels, brakes and tyres

Contents

General description .......... ......................................................................

..

1

Wheels: examination and renovation - wire spoked type .............. 2

Wheels: examinati

on

and renovation - cast alloy type .................... 3

Front wheel: removal and refitting

....

....................

...........................

....

4

Rear wheel: removal and refitting ........................................................

5

Front brake : examination and renovation .................................

...

....... 6

Specifications

Wheels

Type ...............

...

.....................................................

...................................... .

Size ..............................

..

.......

........

.....................

........

...

........

....................... .

Brakes

Type ............................................................................................................. .

Tyres

Size (front and rear) ...........

.......

............................................................... .

Pressures:

Front .

..

...........

....

...

............................

...............

........................

...

..........

.

Rear

...

..........................................

.....

.................................................... .

1

General

description

The Tomos mopeds,

with

the exception

of

the

3ML

model, are

fitted

with

wire

-spoked wheels employing chromium-plated steel rims.

The

3ML

version has cast alloy wheels. In all cases,

16

in diameter

tubed

tyres are

fitted

front and rear.

Brakes are

of

the

cable operated single-leading-shoe (sis)

drum

type

controlled by handlebar levers.

2

Wheels: examination

and

renovation -wire

spoked

type

1 Place

the

machine securely on

its

stand. In the case

of

the front

heel raise the

wheel

clear

of

the ground so that

it

can be turned

-;'

ly

'This

is

best

done by lashing weights

to

the luggage rack.

;ee

S~in

the

wheel

to

check

for

rim alignment. Small lrregularlties can

b

0

rected

by

tightening

the

spokes on the appropriate side

of

the

~

c r

It

should be noted

that

this requires a certain amount

of

skill.

w

de~

:

doubt

the

job

is

best

left

to

a dealer

or

specialist wheel builder.

an

1

'"

'ous

damage such as dents

or

buckling sustained in an

More

seri •

Rear brake: examination and renovation .............

....

...............

....

...

.....

7

Wheel bearings: renewal .....................

...

.................

...................

............

8

Adjusting the front and rear brakes ......................

...

........................

....

g

Tyres: removal, repair and refitting

....

....................

......................

........

10

Valve cores and caps ..............................................................................

11

Wire spoked

with

chromium-

plated

steel rims,

or

cast

ligh

t

alloy

,

depending

on

model

16

in diameter

Internal expanding

drum

brake (front and rear)

16

x 2.

25

in

21

psi

31 psi

accident,

will

require a

new

rim

to

be

built

onto

the hub.

This

must

be

left

to

a professional. . with

3 Check for loose

or

broken spokes by tapping each o

ne

'"

tum d to

a screwdriver. A loose spoke

will

produce a

quit

e different so.un

the

one which

is

correctly tensioned, and

may

be tensioned

by

turnm

~

be

spoke nipple in an anticlockwise direction. Again. care

mus

exercised

when

making adjustments. .

·s

to

be

4 Note

that

if

significant

adjustment

is

needed

or

if a spoker't,is

will

renewed, remove the wheel

and

take

off

the tyre and

tu':

. ff a

fter

allow

the protruding end

of

the

spoke

to

be groun ; .5 lik

ely

adjustment.

If

this precauti

on

is

not

observed, the spoke

en

1

to

puncture the inner tube.

3

Wheels:

examination

and

renovation -cast

alloy

type

---

f

the

tron

t

1 Place the machine securely

on its

stand.

In

the

~ase

0

be turned

wheel, raise the wheel clear

of

the ground so

that

it

can

ck

freely. This is best done by lashing

weights

to

the lugga

.ge

ra

rti

cular

2 Examine the wheel closely

for

signs

of

cracking. paying

:a

natu

re

attention

to

the area around

the

spoke roots.

If

damage of t

15

Chapter 5 Wh

..

ta

.

brekea

end

tyrea

89

is diSCOVercd the

wheal

.should

be

renewed

su

up

by

the crack m

ay

lead

to

sudd

f

at

a

lat

r • g

3 Smaller n

icks

can

be

repal!od

by

care•u r

th

u

ng

a fi

ne

file or abra

SIVG

oapcr

Wh

r

patch

of

comn!on

re

dent

remove O

)(

idc

dcpoS1ts

uslng

ne

abra we

paper

.

In

both

ca s refinish

the

repa

ired

areas

u ng

prim r and

pa

nu

so!d for u

on

alloy

wheels

by

motor acccnsorv Ghops

4

It

should

be

noted

tha

t

-mn

t

the

ma!fltenancc

of

alloy Y<hecls

Is

generally

ear>ler

than

that

of

the

spo

od

type. i

mpact

damage Is les

obvious and may cause

on

uncxpectoo

failure

at

e later

date

. f i

goor811

If

in doubt, seek profes onal advice

or

play

safe end rcn w the wheel.

4

Front

wheel: removal

and

refitting

1 Place the machine securely

on

•ts tand. The

front

wheel

should be

rai5Cd

clear

of

the

ground

. This is

best

done

by

lashi

ng

the rear

of

the

machine

down

or

by

tying

weights

to

the luggage rac .

2 Remove the

nut

and

washer

from

the

end

of

the brake arm

and

disengage the end

of the

inner cable.

Unscrew

the

cable adjuster

and

lodge the cable clear of

the

wheel

Unscrew

the knurled

nng whi

ch

retains the speedometer cable and lodge

this

clear

of

the

wheel

3 Remove both

wheel

spindle nu ts. Pull

the

ends

of

the mudguard

stays clear of the spindle ends

and

lower

the wheel to the ground

4.

2a

Remove

nut

and

washer

(A)

to

free inner cable from cleat then

unscrew adjus

ter (8) and pull cable

clear

of

brake plate

4.3 Remove both

wheel

spindle nuts, displace mudguard stays and

remove

wheel

4 R

fit

the

wh

In

the reverse

of

the above sequence. Ensure

that

the slo

In

th

bre~e

torque arm engages o er the projecting

pin

on

the

l

or

leg

Ch

ck

thal

the specdom ter dri

ve

gearboit is

correctly

pos

uonod

and

th t Its drtvc dog engages fully

In

the hole provided

in

the h

ub

Place the mudguard slays over the spindle ends. then

fit

and

t

igh

ten securely the wheel splndlo

nuts

.

6 Rear

wheel: removal

and

refitting

1 Place the m chine

on its centre stand. Remove the

nut

which

secures the rear brake cable inner

to

the operating arm and disengage

II. Unscrew th e cable adjuster

to

free

the

cable from the wheel.

2 Slacken the wheel sp

indle

nuts

and push the wheel

forwards

until

it

drops clear of the sw

ingi

ng arm slot Disengage the brake torque

arm from the locating

pin

on the swinging arm. Manoeuvre the

wheel

clear

of

the frame, lifting the chain clear

of

the sprocket as

it

is

removed
3 When

refilling

the wheel. check

that

the torque arm engages

correctly over

its pin. Before the spindle

nuts

are tightened, check

.th~t

the chain tension is set to give

20

mm

(f

in) free play. The chain is

adjusled

using the snail cam adjuste

rs

at

the ends

of

the

spindle.

Make

sure that the wheel is aligned in

lhe

frame.

4.

2b

Release knurled ring

to

free speedometer cable

4.4 Ensure

that

speedometer drive

dog

engages as

shown

70

5. 1 Dlsconnecl brake cable, then

st

push

wheel

forward and r move

1t

6

Front

brake: uemination

and

renovation

Important

note

: Bralc

t1

linings

contain asbestos,

11

substance

Jcnown

ro

bt1

toxic

if

inhalttd as dusr. When cleaning brake parrs.

work

in rhe

open.

Wherever possible. use

an

industrial safety mask. Wipe our any

dusr w1rh

a

petrol

moistened

rag

and

dispose

of

rhe rag safely sfrer

use.

On

no

account use compressed

sir

to

clean brake parrs.

fig.

6.1

Front

brake

and

hub

components

access

to

the

front

brake

It

will first

be

~

1

To

s::'

front

wheel

as

described

in

Section

4.

With

the

to

~

unscntW

the

nut

which

retains

the

brake plate

to

the

:::::

IP

ndle end

hh

ft

away

2

Examine

the

brake linings

for

wea!

?r

contamination. No

l>r9Clle

wear limits

are

aY11llable,

but

If

either hmng has

~m

to

within

•bout

1

mm

of

the backing

metal. renew

1hem as a pair.

3

If

oil

or grease has

found

its

way

onto

the lining meterlil It

11

mportanl

to

rectify tho source

of

the problem prior

to

reassembly

Ugh

t contamlno don can

be

troaled

by

degreasing the

shoes,

Using

pelrol

or

a similar d greasing solvent.

If

the problem

Is

more

aertoua,

r

new

the shoos.

4

To remove 1he sho s. place the brake plate on the workbench

grasp the

shoos and

fold

' them

togeth~r

until spring

pressure

~

released Disengage

1he

shoes from

the

springs and place them to

one

side.

5 Check

ihat

the brake operating arm and cam arrangement

move

smoothly.

It

is advisable

to

remove and clean the cam each time

the

shoes are renewed. Unscrew the

nut

which

retains the arm to the

cam

Uh

away

the arm. then displace

1he

cam from the brake plate. '

6 Clean

off

all traces

of

old grease and check the cam and its

bore

for wear. Before refitting the cam. apply a film

of

grease to It.

Take

care

1o

avoid excess grease finding its

way

into

the brake.

7

Wipe

out the brake drum

with

a petrol moistened rag

and

inspect

ils

surface

If

badly scored. braking efficiency

will

be impaired.

In

exlreme cases

1he

drum must be rene

wed

. Lighter scoring or slight

ovalily

can

be

corrected

by

having

the

drum

surface skimmed.

Consult

a Tomas dealer for advice

on

this

point

.

a To reassemble

1he

shoes,

fil

the return springs then force

the

shoes apart, holding them in a ·v· formation. Position the

assembly

over the pivot and cam then snap them

into

place by pushing

down

and spreading the shoes. There is a certain knack

to

this, and

excessive

force should

not

be required

if

done correctly.

1

Wheel

hub

2 Brake shoe - 2

off

3 Brake

plate

4

Return

spring

- 2

off

5

Wheel

spindle

6 Washer - 2

off

7

Wheel

spindle

nut

- 2

off

8

locknut

- 2

off

9

Spacer

1 O

Wheel

bearing - 2

off

11

Spacer

12

Dust

cover

13

Brake operating cam

14 Washer
15

Nut

16 Brake operating

arm

17

Bolt

18

Washer - 2

off

19

Bush

20

Cable cleat

21

Washer

22

Speedometer drive gearbox

23

Spacer

p

Chapter 5 Wheels,

brakes

and

tyres

71

7

Rear

brake: examination

and

renovation

1

To

gain access

to

th~

rear_ brake

i

~

will first

be

necess

ary

to

remove

tile rear

wh

eel as

~escribe_d

tn

Section 5.

With

the wheel removed,

unscrew the

nut

which

retains

the brake

plate

to

the

wheel spindle

and

7.1

Brake

plate can be removed

after

nut

has been run o

ff

the

whe

el

spindle

li

ft

it

away

.

2 The b

ra

ke assembly

is

essentially

the

same

as

the

front

unit.

and

the

procedu

re

for

inspecti

on

and overhaul is identical. Refer

to

Section

6

for

details . paying particular

attention

to

tho

note

regarding

the

dangers

of

asbestos

at the beginning

of

this

Section

.

7.2

Re

ar brake asse

mbly

is similar

to

front

except

for

torque

arm

'

18

21

20

19

~----"""Tim»mL®Tu

~

~

16

17

1

Wheel

hub

2

Brake

plate

1

Fig.

5.2

Rear

brake

and

hub

components

3

Brake

shoe - 2

off

4

Return

spring

- 2

off

6 Brake

operating

cam

6 Washer

7 Brake

operating

arm

8

Washer

9

Nut-2off

10

Chain

tensioner

cam

11 Rear

wheel sprucket

1 2 B

oft

- 4

off

13

Nut-4off

14

Tab

washer

- 2

off

1 5

Wheel

spindle

16 Was

her

- 2

off

1 7 Whe

el

spindle

nut

- 2

off

18

locknut

- 2

off

19

Spacer-2

off

20

Wheel

bearing

- 2

off

21

Spacer

22

Spacer

23

Final

drive chain

24

Chain

master

link

25

Washer

26

Cable

cleat

27

Bush

I

.............

,.. ....

1 Bolh

1he

fronc

end

,..,

..,..

9"8

IUCIPOft9d

on

lcJurne

bel

bw'•llL

The

.,,..-..m

ii

9lmos1

ldential

on

Hd1

wheel.

with

me

~of

en eddltionel disi.nc:e piece

tted

on

the

right-hand

end

of

1he

,_,

whMI

l!pirde

The

tnpecl.Ne

erBng.mentl

Int

lhowr\ In

1he

eocomp•o'J'l"G

line

drawing•

.

2

The

condition of

the

burings

can

be

checked

by

att9mpting

to

rodl

lhe

wheel

from

9icte

to

side

If

more

than

about

i

mm

of frM

play

can

be

f91t

at

the

wheel

nm.

the

bHong1o ahoutd be renewed Star1

by

'9mCMng

the

~I

11

delCfl>ed n Section 4 °' 5

3 Run

on

the wne.1

IPlndt•

nuts and remove

the

IP•cers

Umcrew

lhe

nut

whictl retains the brake plate a

mbfy

and

remove

the

bra!r.e

plate

IPe<:«

(wtlefe fined) end

the

wheel e

4 P

aa

• long

drift

through

the

hub

end lever the emal

spacer

to

ona side

Support

the

hub

than

driv

out

the

opposite

beanng

Remove

the

bearing

and spacer nvert

the

wheel

and

drive

out

the

remaining bearing

5 Grease

the

new bearings

then

drive

th

m i

nto

the

hub

u g a

18rge

IOCket H e

drift

Ma

e aure

that

the

bearings enter

the

bore

9e1

u1rely

and fully. Do

not omit the Internal spacer Complete r •

auembty

by

reversing

the

d smanthng sequ nee.

9

Adjusting

tha

fro

nt

and

rear brek11

1 The front

and

rear brakoa aro

op

rated

by

th right

and

loft

·hand

brake levers respectively, each

of which la provided wi

th

a threaded

adjuster

In

order

that

brake shoo wear can

be

compensated for

by

eff

ectively taking

up

play

In

the

operet1ng cable. The setting

of

the

brake levers

Is

largely a

mattor

of

discretion

on

the part

of

the

individual

owner, but

aa a goneral guide,

11

cen

be

considered that each

brake

should

commence operati

on

as soon as the lever is applied

When

setting

the

brakes, check

that

the shoes free

off

completely as

a

ny

&light

binding

wm

have a

mar1<ed

effect

on

the performance

of

the

ma

chine.

2 S

hould

the range

of

adjustment prove insufficien

t.

it

is possible

to

short

en

the

cable

at

the

point

at

which

it

is

attached

to

the brake

actu

at

ing arm. Rele ase the screw and

nut

which clamps the inner

c

ab

le to the small pressed steel cleat. The cable can

now

be

disengaged and repositioned

in

the

cleat. and the securing

nut

tightened. Final

fin

e ad

justmen

t should be carried

out

in

the no rmal

way

.

10

Tyres: removal,

repair

and

refitting

1

At

some time

or

other

the

need will arise to remove and replace

the

tyres. ei

ther

as a result

of

a puncture

or

because replacemen

ts

are

necessary

to

offset

wear

. To the inexperienced. tyre changing

represents a

formidab

le task,

yet

if a few simp

le rules are observed and

the

technique learned, the

who

le operati

on

is surprisingly simple.

2

To

remove the tyre from either wheel, first detach the wheel from

the

machine. Deflate the tyre

by

removing the valve core, and

when

the

tyre is fully deflated. push

the

bead away from the wheel

rim

on

both

sides

so

that the bead enters the centre well

of

the

rim. Remove

the

locking ring and push the tyre valve

into

the

tyre itself.

3 Insert a tyre lever

close

~

the valve and lever the edge

of

the tyre

over

the outside

of

the

rim

. Very little force should be necessary;

if

resistance Is encountered

it

is probably due

to

the fact

that

the tyre

beads have

not

entered

the

well

of

the rim all

the

way

round.

If

aluminium

rims are fitted, damage

to

the soft alloy by tyre levers can

be

prevented

by

the

use

of

plastic rim protectors.

4 Once

the

tyre has been edged over the wheel rim.

it

is easy

to

work

round

the

wheel rim so that the tyre is completely free from one

side.

At

this

stage

the

inner tube can be removed.

5

Now

working

from

the

other

side

of

the

wheel, ease the other

edge

of

the

tyre over

the

outside

of

the

wheel rim that

is

furthest away.

Continue

to

work

around

the

rim until

the

tyre is completely free from

the

rim

.

e

If

a

puncture

has neceseltated

the

removal of the tyre, reinflate the

Inner

tube

and

Immerse

It

In

a

bowl

of

water

to

trace the source

of

the

leek.

Mark

the

po9ition

of

the leak.

and

deflate

the

tube.

Dry

the

tube,

8

1

Note

ddi

tional spacer

on rear

wheel

spindle

and clean the area around the

puncture wit

.h a petrol

soa~ed

rag.

When the surface has dried, a

pply

rubber

solution

and

~llow

this to

dry

bnfore removing the backing from

the patch, and applying the patch

to

the surface. . . . .

7

It

is

best

to

use a

patch

of self vulcanizing type,

which

will form a

permanent repair.

Note that

it

may

be

necessary

t~

remove a

protective covering from

the

top surf

ace of t

he

pat

ch after

11

has

sealed

into position. Inner tubes made

fro

m a special synthetic rubber

may

require a special type

of

patch

and adhesive, if a satisfactory

bond

is

to

be achieved.

8 Before replacing

the

tyre, check

the

inside

to

make sure that

the

article that caused

the

puncture

is

not still

trapped inside the

tyre

.

Check the outside

of

the

tyre, particularly t

he

tread area,

to

make

sure

nothing is trapped

that

may

cause a fu

rth

er

puncture

.

9

If

the inner tube has been patched on a

number

of

past occasions .

or

if

there is a tear

or

large hole,

it

is preferable

to

discard it and fit a

replacement. Sudden deflation

may

cause

an

accident, particularly

if

it

occurs

with

the rear wheel.

10

To

replace the tyre.

inflate

the

inner tube

for

it

just

to

assume

a

circular shape but only

to

that amount,

and

then

push the tube into

the

tyre so

that

it

is enclosed completely. Lay

the

tyre

on

the wheel at

an

angle. and insert the valve thr

oug

h the hole

in

the

wheel rim. Attach

the locking ring

on the first few threads, sufficient

to

hold the

valve

captive in its c

orr

ect location.

11

Starting

at

the

point furthest

from

the

valve, push the tyre

bead

over the edge

of the

wheel rim

until

it

is

located

in

the central well.

Continue

to

work around the tyre

in

this

fashion

until

the whole

of

one

side

of

the tyre

is

on

the

rim.

It

may

be necessary

to

use a tyre

lever

during the final stage

s.

12

Make sure there

is

no

pull

on

the

tyre valve and

again

commencing

with

the

area

furthest

from

the

valve. ease the other

bead

of

the

tyre over

the

edge

of

the

rim. Finish

with

the area close

to

the

valve. pushing

the

valve

up

into

the

tyre

to

ensure

that

the inner

tu~

is

not

trapped

when

the

last

section

of

bead is edged over the rim with

a tyre lever.

1 3 Check

that

the

inner

tube

is

not

trapped

at

any point. Reinflate

the

inner tube, and check

that

the

tyre is seating correctly around the

wh

eel rim. There should be a

thin

rib

moulded around

the

wall

of

the

tyre

on

both

sides,

which

should

be

an equal distance from

the~

rim

at

all points.

If

the tyre is unevenly located

on

the

rim.

try

boUn~

the wheel

when

the

tyre

is

at

the

recommended pressure.

It

11

probable that one

of

the beads has

not

pulled clear

of

the

centre well

14

Always run

the

tyres

at

the

recommended pressures and

never

under

or

over inflate. The correct pressures are given

in

the

SpeClfiCl-

tions

Section

of

this Chapter.

1 5 Tyre replacement

is

aided

by

dusting

the

side walls. partlculartv

In

the vicinity

of

the

beads,

with

a liberal

coating

of

frenCh

ctlllk-

Washing

up

liquid

can also

be

used

to

good

effect.

but

this

hal

the

disadvantage, where steel

rims

are

used

of

causing

the

Inner

9UffaGI

of

the

wheel

rim

to

rust. '

\"1en

h~t

bt>:td

·~

c-ll"ar, r l"mov1.'

t\

re

·"

~hown

Lav

tyre

on

nm

and feed valve

through

hole

rn

nm

U..

limii.

technique

for

second

bead.

finish

et

tVnt valve

PGlition

U

two

I

Villi

10

wor

I\

head

011111 1h1 edge

of

rim

Tyre frttrng:

lnflato

rnnor tube ond rnsert rn

tyre

Work

first

bead

over

rim,

usrng lever

in

final

section

Pus~

valve

~d

tube

up

into

tyre

when

fitting final HCtion,

to

llVOtd

trepptng

74

Chapt• 5 Wh

..

I•

. brakes end tyres

11

Velv•

cor

..

end

ceps

-----

1

v~ive

cores

sel

dom

giv

e t

rouble. but

do

not

last

inde;:----

u I' . I in1tely D·

under the

sea

ting will

cause

.a

pu~

mg

sow

-puncture'.

Che

· 1

11

...

~re

not leaking

by

applying

spittle

to

the

end

of

the ck

that

b-·

.

W~a

wat

chi

ng fof air

bubbl

es. •

f'ld

2

A valve

cap

is a safe

ty

device

.•

and

should

always

be

fitted

fr

om

keepi

ng

dirt

out

of

the

valve. 1t

pro~ldes

a second seal

in

~8~a11

Ive

failure

and

may

prevent

an acc

ident

resulting fro

se

of

VII

• • m

SUdden

deflat

ion

.

Chapter 6

Electrical system

contents

General

description

...

............................................................................... 1

Checki

ng

the electrical system: general .........................

...

.................. 2

He

ad

lamp: bulb renewal and adjustment ........................................... 3

Speedometer: bulb renewal .........

....

.........................

..............

............... 4

Specifications

Generator

Type

....

.....................

........

............................................................................ .

Output

..

..........................

....

...........................

....

...............................

.......

....

.

Bulbs

Headlamp .............................

...

................................................................... .

Headlamp

pilot

lamp .......

.........

............................................................... .

Speedometer ............

............

...

.........................................

......................

...

.

Tail lamp ...

..

.......................

......

....

..................

......

.............................

.......

... .

Stop lamp .

...

................................

............................................................... .

Turn signal

lamp .....

...

............

..........................

..........

...

....

...

...

.......

....

......

. .

General

description

The

Tomas mopeds are

fitted

with

a 6

volt

flywheel generator

unit

.

The

generator

output

is alternating current (acl and

is

used unrectified

to power the electrical system.

No

voltage regulat i

on

is

prov~ded

,

the

output of the lighting coil s having been matched

to

the requirements

of the lighting system over a broad spread

of

engine speeds. An

electric horn completes

the

standard system.

The

A3MS

model

is

fitted

with

turn

signals, powered

by

a separate

lighting coil in the flywheel magneto.

2 Checking

the

electrical

system:

general

As

has already been intimated,

the

electrical system

i~

of

~imple

des

ign, with

few

component parts

which

are likely

to

give rise

to

problems. Apart from the more

common

failures such

as

blown

b~lbs,

corrod

ed contacts or damaged

wiring, the

system should prove reliable

for the life of the machine.

2 In the event of problems

which

cannot be attributed

to

a~

obvio.us

fault,

it

will be necessary

to

test the generator coils. This

will

require

the

use

of

a certain amount

of

test

equipment. and

in

the absence

of

detailed specifications the

test

must

be entrusted

to

a Tomos dealer

or

be

carried out

by

substituting a generator

which

is

known

to

be sound.

3 Headlamp:

bulb

renewal

and

adjustment

1

Remove the three screws

which

retain the headlamp reflector

assembly to the shell and

lift

it

away. Take care

not

to

drop the bulb,

Which

is held

in

position

by

the contacts inside the shell. .

2 When fitting a new bulb, ensure

it

is

of

the

correc~

rating (eV

l

SW).

This is important

if the load

on

the lighting system

is

to

be kept

balanced

. The use

of

bulbs

of

the

wrong

wattage

may lead

to

frequent

failure or poor lighting performances. · f the
3

The

pilot lamp bulb

is

housed

in

the

headlamp shell.

It

is

0

St

op/

tail lamp:

bulb

renewal ................

...

............................................. .

Switches: location and maintenance ......

......

.......................

...

.........

...

.

Horn: locati

on .....

...................................

....

.............................................. .

Wiring: examination and maintenance ...

......

...................................... .

Ducati

6v

flywheel generator

20/15W

6V

15W

6V 1

5W

Festoon

6V

1.2W

6V

5W

6V

15W

6V

10W

5

6

7

8

festoon type and is also rated

at

15W.

Renewal

is

a simple

matter

of

pulling

it

out

from between the contacts

which

hold

it

in

position

in

the

sh

ell. When fitting a

new

bulb, check

that

the

contacts

grip

the
terminals securely.
4 The headlamp beam height

may

be

set

by

slackening the

headlamp mounting bolts and pivoting

the

unit

to

the required

position. Note

that

the beam should

be set

with

the rider seated
normally.
5 The easiest

way

to

find

the

optimum

setting

is

to

ride the machine
at

night

with

the

bolts

left

slightly slack, so

that

adjustments can be

made on the road. Do

not

be

tempted

to

set the beam

too

high;

the

headlamp is

of

limited

power

and much

of

the available

output

will

be

lost. When the best setting has been found, tighten the

mounting

bolts.

3.1

a Release reflector

unit

from

shell ...

Y contacts inside shell

3

3 Pilot bulb is

held b

~

17

19

20

L

i 16

j:)i~

Fig.

8.1

Electrl I

~

cJ

ca systemc

omponents

9

; Headlamp assembl
3 Reflector unit

Y

4

H~adlamp

bulb

5

Pilot

lamp bulb

6

Screw_ 3 off
Bolt

- 2

off

~

~ock-washer

- 2 off

9

andlebar switch

Horn

10

s .

11

8

~~;ng

washer

12

Tail lamp lens

13

Tail/amp bulb

14

Stop lamp bulb

jiP

Chapter

6 Electrical

system

77

Speedometer :

bulb

renewal

4~------~~~~-:-~~~~~~~~~~

;-=-The speedomeTter

ill_umination

l~mp

is a

push-fit

in the undersi

de

f

the

instrument. o gain access

to 1t, remove the headlamp

mounting

0

It to free the plast

ic nacelle. Pull

out

the bulb holder and remove

~e

~ulb

.

Ensure

that

the replacement

bulb

is

rated

at

6V

1.2W.

5

Stop/

tail

lamp: bulb

renewal

1

Release

the tail

l~mp

lens

by unsc

rewing

the

tw~

retaining screws.

The

unit is fitted

with

separate

bulbs

for the tail and brake

lamp

ircuits. each being a bayonet

fitti

ng

in

its

holder.

~

When fitting

new

bulbs.

note that

the

tail

lamp

is

rated

at

6V SW,

and the

stop lamp

at

6V 1 SW

. Take care

not

to

overtighten

the

lens

screws during

reassembly.

6 Switches :

location

and

maintenance

Handlebar

switches

1

Th

e left-hand

switch

assembly incorporates the lighting. horn and

engine

kill switches. The

switche

s are housed in a sealed plastic box

4.1 Speedometer

lamp

is

push-

fit

in back

of

instrument

6

·

1 Switch

unit

is retained

to

holder

by

two

screws

retained

by

two

screws

to

the handlebar bracket. On machines

with

tum

signal

s.

a similar

switch

unit

is fitted

to

the

right

-hand

end

of

the

handlebar.
2

In

the

event

of

swit

ch problems.

try

introducing a silicone-based

maintenance spray, such as

WO 40. Operate

the

switch

repeatedly

to

distribute

the

fluid.

If

this fails

to

resolve

tho

problem, flt a

new

switch

assembly. The unit

is

of

sealed construction,

making

repair

imprac-

ticable.

Brake

lamp

switches

3 The brake lamp switches are housed In

the

lever stocks and are

of

the

plunger type. The

most

likely cause

of

trouble

is

water

getting

inside the rubber

boot

which covers

the

switch

lead terminals. Pull

off

the rubber

boot

and check

that

the

terminals are

dry

and secure.

If

this

fai

ls

to

effect a cure. renew

the

switch.

7

Horn: location

1 The horn is bolted

to

the

lower

yoke, beneath

the

headlamp

unit.

In the event

of

a malfunction. check

that

the

horn lead

terminals

are

secure and

clean. and

that

the

horn

wiring

has

not

been

damaged. If

the problem persists, renew the

horn

.

5.1 Stop/tail lamp uses separate bulbs

6.2

If

switch fails

it must be renewed together

with

wiring

Chapter e Electricel

system

6.3

Brake

S\\

tch

screws

into

lever

stoc

8

Wiri

ng .

examination

and

maintenance

The

wrnng

harness is colour-coded. the various leads

COIT8sponding

with

those

shown

in

the accompanying

wiring

diagrams. The harness consists

of a front

section, the tail

lamp

wiring

and

the

generator

output

leads and these join at Lucar connectors

beneath the

left-hand

engine shroud.

2 Visual inspection

will

show

whether

there are any breaks

or

7.1 Horn

is

bolted

to

lower

yoke

damaged

outer

cove~in~s

which.

could

give rise

to

short

circuits.

Another

vulnerable

point

1s

the

various

connectors which may

become

detached, waterlogged

or

corroded. These should be

checked

and

cleaned whenever there

afe

electrical faults.

3

Intermittent

faults

are

inv

ariably

the

most

difficult

to

trace

and

can

often result

from

a loose connection.

Another

common

cause

is

a

chafed

wire

causing an occasional

short

circuit

where

it

rubs

on

the

frame

or

engine. Check each

wiring

run

carefully and repair

the

damaged casing

with

insulating

tape

or

renew

the lead.

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5 ·

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9 ·

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11 · TAIL

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12 · STOP

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Wiring

diagram -A3MS

and

A3ML

models

@

)

Conversion

factors

Length

(distance}

x

25.4

lnc:heS

(In)

-

Millimetres

Imm)

x

0.0394

..

lnchn

(In)

Feet

(ft}

x

0305

=Metres

(ml

x

3.281

=Feet

(ft)

Mllel

x

1.609

=

Kilometres

(km) x 0.621

..

Miles

volume (capacity}

CUbiC

Inches (cu

in;

in

3

)

x

16.387

Cubic

centimetres

(cc;

cm

3

)

x

0.061

= Cubic inches (cu

in;

ln

1

1

imperial pints

(Imp

pt)

x

0.568

.-..

Litres (II x

1.76

= Imperial

pints

(Imp

pt)

1

mper1al

quarts (Imp

qt)

x

1.

137

Litres Ill

x

088

= Imperial

quarts

(Imp

qt)

Imperial quartS

(Imp

qt)

x 1.201

=

US

quarts

(US

qt)

x

0.833

= Imperial quarts

(Imp

qt)

us

quarts (US

qt)

x

0.946

=

litres

Ill

x

1.

057

US quarts (US

qt)

imperial gallons

(Imp

gal)

x

4.546

-

litres

(I)

x

0.22

= Imperial

gallons

(Imp

gal)

imperial gallons (Imp gal)

x

1.201

US

gallons

(US gal)

x

0.833

= Imperial gallons

(Imp

gal)

us

gallons (US gal)

x

3.7

85

Litres Ill

x

0.264

= US gallons (US gal)

Mass

(weight)

Ounces

(oz)

x

28.35

- Grams (g)

x

0.

035

Ounces (oz)

Pounds

(lb)

x

0.

454

- Kilograms (kg)

x

2.205

- Pounds (lb)

Force

Ounces-force (ozf; oz)

x

0.278

=

Newtons

(N)

x

3.6

= Ounces-force (ozf; oz)

Pounds

-force (lbf; lb)

x

4.

448

=

Newtons

(NI

x

0.225

= Pounds-force

(lbf

; lb)

Newtons (N)

x

0.1

= Kilograms-force (kgf; kg)

x

9.81

=

Newtons

(N)

Pressure

Pounds-force per square

inch

x

0.

070

= Kilograms-force per square

x

14.223

= Pounds-force

per

square

inch

(psi;

lbf

/in

2

;

lb/in

2

)

centimetre (kgf/cm

2

; kg/cm

2

)

(psi;

lbf

/in

2

;

lb/in

2

)

Pounds-force

per

square

inch

x

0.068

= Atmospheres (atm)

x

14.696

= Pounds-force

per

square

inch

(psi;

lbf/in

2

;

lb/in

2

)

(psi;

lbf/in

2

;

lb/in

2

)

Pounds-force per square

inch

x

0.069

= Bars

x

14.5

= Pounds-force

per

square

inch

(psi;

lbf/in

2

;

lb/in

2

)

(psi;

lbf/in

2

;

lb/in

2

)

Pounds-force

per

square inch

x

6.895

= Kilopascals (kPa)

x

0.145

= Pounds-force

per

square

inch

(psi;

lbf/in

2

;

lb/in

2

)

(psi;

lbf/in

2

;

lb/in

2

)

Kilopascals (kPa)

x

0.01

= Kilograms-force per square

x

98.1

= Kilopascals (kPa)

centimetre

(kgf/cm

2

;

kg/cm

2

)

Torque

(moment

of

force)

= Kilograms-force centimetre

x

0

.868

= Pounds-force inches

Pounds-force inches

x

1.

152

(lbf in;

lb

in)

(kgf

cm;

kg cm)

(lbf

in;

lb

in)

Pounds-force inches

x

o.

113

=

Newton

metres (Nm)

x

8.85

= Pounds-force inches

(lbf

in;

lb

in)
llbf in; lb in)
Pounds-force inches

x

0.

083

= Pounds-force

feet

(lbf

ft

;

lb

ft)

x

12

= Pounds-force inches

(lbf in;

lb

in)
llbf in;

lb

in)

Pounds-force feet

(lbf

ft

;

lb

ft)

x

0

.13

8

= Kilograms-force metres

x

7.233

= Pounds-force

feet

(lbf

ft

;

lb

ft)

(kgf

m; kg m)

Pounds-force

feet

(lbf

ft;

lb

ft)

x

1.356

=

Newton

metres (Nm)

x

0.738

= Pounds-force

feet

(lbf

ft;

lb

ft)

Newton metres (Nm)

x

0.102

= Kilograms-force metres

x

9.804

=

Newton

metres (Nm)

(kgf

m:

kg

ml

Power

Horsepower (hp)

x

745

.7

=

Watts

(Wl

x 0.

0013

= Horsepower (hp)

V!locity (speed)

Miles per

hour

(miles/hr:

mph)

x

1.609

= Kilometres per

hour

(km/hr: kph) X

0.621 =

Miles

per

hour

(miles/hr;

mphl

Fuel

consumption•

= Kilometres

per

litre (km/II

x 2.

825

:Hes

per gallon, Imperial (mpg)

x

0.

354

Ilea

per gallon,

US

(mpg)

x

0.425

= Kilometres

per

litre (km/II

x

2.352

Temperature

Deuriea

F.t"enheit

= (°C x 1.8) +

32

Degrees Cel1lu1

(Degre•

Centigrade;

•C)

Index

A

About

this

menuel 2

AcceAorles

12

~edgementa

2

Adjustments

:-

br1ke1

23. 72

cerburettor 62
conllct

breeker gsp

64

flnsl drive ch1in

22

he1dl1mp besm height

76

idle

speed

2 3

Ignition timing

56

spirit

plug g1p

56

steering heed bearings

26

. 62

Air

filter 25.

52

B

Baffle -exhaust

22

Barrel -

cylinder:-

examination and renovation

31

refitting

44

remov1I

29

BNm

height

-

hNdlemp

75

BNrings:-

big-end

32

gearbox

33

main

33. 39

small-end

32

steering head 25,

62

swinging arm

25,

64

wheel

25

. 72

Brekes:-

adjustment 23. 72
examination and renovation

70.

71

fault diagnosis 18

stop

lamp

switches

77

Bulbs:-

c

headlamp

75

specifications

75

speedometer

77

stop/tail lamp

77

Cable -lubrication

24

Carburettor

:-

adjustment

23

,

52

dismantling, examination and reassembly

50

removal and refitting

50

Centre

stand:-

examination

66

lubrication

22

Chain:-

final drive

22

. 27.

45

primary

30

Check1 :-

br1kes

23

condenser

56

contact breaker

point•

25

. 54

electrical system

23

.

75

fitt

ings and f11teners 2 5

gearbox oil level

22

idle speed

23

ignition coil

56

Ignition timing

56

spark plug 22.

56

steering head bearings 2 5
swinging arm bushes 2 5
wheels

25

Choo1lng end

fitting

ecceHorlH

1 2

Cleenlng:-

air filter element

2 5.

52

exhaust battle

22. 52

fuel tank and tap

49

the machine 21 .

66

Clutch:

-

centrifugal:

examination and renovation

34

refitting

40

removal

30

roller

36

Coll

:-

generator

75

ignition

56

Condenser

56

• ,

Contact

breaker

points

54

Conversion

factors

81

CrenkcHe

halves:-

examination and renovation

34

jo

ining

39

separating

31

Crenkshaft

:-

end-float

39

examination

and

renovation

32

refitting

39

removal

31

Cylinder

barrel

:-

examination

and

renovation 31

refitting

44

removal

29

Cylinder

heed:-

D

examinati

on

and renovation 31

refitting

44

removal

29

Decarbonlsatlon

:-

engine

25

exhaust 22.

53

Dimensions

and

weights

6

Dismantling

the

engine/gearbox

unit

. .

Dust

caps -tyre

valvea

74

-

prehmtnariea

29

/

t

E

·

cal

system

:-

Elec:'ake lamp

switches

71

heck 23.

75

~ault

diagnosi~

~

9

general descnpttOn

75

nandlebar

switch

7 7

headlamp

75

horn 71

spee00meter 67.

71

wiring:

diagrams

79

.

80

examination and

maintenance

78

Engine:-

bearings:

big-end

32

main 33.

39

small-end 32

crankcase halves 31. 34.

39

crankshaft 31. 32.

39

cylinder barrel 29. 31.

44

cylinder head 29. 31.

44

decarbonisation

25

dismantling - general

29

examination and

renovation -general

31

fault diagnosis

14

general description

21

piston

29

. 31 .

44

reassembly - general

38

refitting

45

removal

27

special tools

27

specifications 2 6
starting and running

the

rebuilt

engine

48

Exhaust

system

22. 52

F

Fault diagnosis

14-19

Filter -

air

25. 52

Final drive

chain

:-

adjustment and maintenance

22

refitting

45

removal

27

Final

drive

sprocket

:-

refitting

45

removal

30

Fittings

and

fasteners

check

2 5

Flywheel

generator

:-

components

54

refitting

43

removal

30

Frame and

forks

:-

Centre stand

67
fault diagnosis 1 8
frame

63

front forks

25.

59

general description

59

specifications

59

steering head

25

, 61.

62

swinging arm

25.

64

Front brake:-

adjustment

23,

72
fault diagnosis 1 8
examination and renovation

70

stop switch

77

Front

wheel

:-

bearings

72

examination and renovation 25.

68

removal and refitting

69

Fuel

svstem:-

carburettor 23. 50,

52

fault diagnosis 14,

15

general description

49

Index

pipe

50

specifications

49

tank

49

tap

49

G

GNrbox:-

bearings and oil seals

33

dismantling. overhaul and reassembly

36

fault diagnosis 1 7
oil

change

24

oil level check

22

refitting

40

removal

30

Generetor:-

components

54

refitting

43

removal

30

Gudgeon

pin

:-

refitting

44

removal

30

H

Hendleber

twltchn

71

Heedlamp

75

Hom

71

Idle

speed

check

23

Ignition

system

:-

coil

56

condenser

56

contact breaker

points

54

fault diagnosis 1 5
flywheel generator

30, 43,

54

general description

54

spark plug 22,

56

specifications

54

timing

56

Input

shaft

:-

overhaul

36

refitting

40

removal

30

K

Kickstart

:-

L

examination and renovation

38

refitting

40

removal

30

Lamps:-

headlamp

75

specifications 7 5
speedometer

77

stop/tail

lamp

77

Lubrication:-

control cables

24

control lever pivots

22

final drive chain

22

front

fork tubes

25

gearbox oil :

change

24

level check

22

general description

49

stand

pivots

22

83

&84~~~~~~~~~~~~~~~~----_::'":ldeJl::------------------~--~~~-------

-

---

s~

f"

a

ti

on•

- m 7 5

M

Ma

n

bNttngs 33.

39

Maintenance

-

'°"'-"'•

2 I 2 5

0

011

- g

..

rboa

·-

c

hange

24

leV!!I

22

Oil

...

,.

33

39

Or-dering spare

perta

7

Output

theft'.•

p

overi\aul

36

refitting 40

removal

30

Petrol

:-

leed

pipe

50

tank

49

tip

49

Pl1ton:-

eum

ination and renovat ion

31

r

efining

44

removal

29

P

ist

on

ring•

3 1

Preuurn -tyre

68

Primery

drive

ctt.ln

30

R

R

..

r

breke

:-

adjustment

23

, 72

examination and renovation

71

fault diagnosis 18
stop lamp switch 7 7

R

..

rwheel

:-

bearings

72

examination and renovation 25,

68

removal and refitting

69

Refitting

the

engine/gearbox

into

the

frame

45

Removing

the

engine/gearbox

from

the

frame

27

Roller

clutch

36

Routine

maintenance

21-2 5

s

Safety

first 8

Small-end

bush

32

Spenner

size

comparison

11

Spareperts -ordering

7

Spark

plug

:-

check 22.

56

colour chart

57

specifications

54

Special

tools

27

e' nc.al svst

ogine

26

flame

end fo1 s 59 ,

fuel svstem

and

lubric

ati

on

49

lgnllion

svstem

5

4

uan

S.111ls.!lon

27

wheels

bra

kes

ond

tyres 68

speedometer

:-

bulb

77

dri

ve c11bfe

66

head

66

Stand

66

.

St•rtlng

and

running

the

rebuilt

engine

48

Steering

heed

:-

bearings

2 5.

62

dismantling

and overhaul

60

Stop/t•ll

l•mP

7 7

Swinging

erm

2 5.

64

Switches

77

T

Timing

- igni

tion

56

Tools

end

working

fecilltles

9

Torque

wrench

settings

11,

27

Trensmission

:-

ce

ntrifugal clutch

:

examination and

renovation

34

refitting

40

removal

30

fa

ult

diagnosis 1 7

gearbox:

bearings and

oil

seals

33

dismantling

. overhaul

and

reassembly

36

refitting

40

removal

30

oil change

24

oil

level check

22

roller clutch 36

Tyres

:-

v

colour sequence

73

pressures

and

size

68

removal, repair

and

refitting

72

valve

74

Valve -tyre

74

w

Weights

and

dimensions

6

Wheels

:-

bearings

72

check and

overhaul

25

examination

and

renovation

68

removal

and

refittiag

69

1 • .

Wiring

:-

diagrams 79,

80

e~ami

nation

and

maintenance

78

Working

facilities

9

Printed

by

Haynes

Publishing

Group

Spark

ford

Yeovil

Somerset

England

Models

covered

by

this

manual

Tomos A3K. 49c:c traduced o ember

1982

Tomos A3M. 49cc. Introduced August

1984

Tomos A3MS 49cc Introduced

July

1984

Tomos A3ML 49cc Introduced July

1984

Cie

to

know

your

motorcycle

a little better

The clear.

step by·

step

illustrated

instructions

cover

the

dismantling

.

rnspectton,

repair

and

refitting

of

the

engine, clutch

and

gearbox. cooling

system

(where

f1ttedl.

fuel

end

lubrication

systems

. 1gnrt1on

and

exhaust

systems.

frame

and

forks.

wheels.

brakes

and

tyres. and

the

electrical

system.

Routine

maintenance.

complete

spec1f1cat1ons

and

detailed

fault

d1agnos1s

procedures

are

also

included. Only

Haynes

completely

strip

and

rebuild

the

motorcycle

on

which

each

manual

is based.

Saving

you

mon

e

start

to fin·

Whether

you

iust

want

to

change

your

011,

repla

ce

your

p

top

end

overhaul

or

rebuild

your

gearbox.

the Haynes

r.

you

how

and

can

help

save

substan

tial a .-

on

servicing

and

repair bills

Helping

you

make

t

a little

furth

er

go

A

Haynes

manual

can

help

you

stretch

your

motorcycling

budget

that

little

bit

further

in

other

ways

too.

Regular

maintenance

and

servicing

will

mean

~hat

your

motorcycle

is

safer

to

ride

whilst

giving

you

more

of

those

precious

mpg.

What's

more. a motorcycle

that

is

well

looked

after

will

hold

its

price

better and

last a lot

longer.

AIC:O!

'""'•

,,......,

"""''

ISBN 1 85010

062

4

What

the

press

say

with

twlp

from these

nhmti.lls

puhlislrnci by

H,1ynps you

c,1n

by

following

stl'p

by step

intruct1ons perform

rust

.ihout

PVNy maintenance

rnsk

you

II

ever need to

keep

your

bike running for

yeilrs

We

heartily

rPcommend

them·

~

Cvclt>

World

!USA/

H,1ynes manuals

.issume

that the owner

will

not

have factory tools.

and alterna11ves

are either

s

hown

or discussed .

Cycle

fUSAI

a

well

illustrated

manual

written

in

everyday language

Motor

Cycle

News

(UK!

They

show

simple

to
foHow step-by· step
overhauls

and are well

illus

trated

Motorcycle

Mechanics

fUKI