Polaris 1973 TX Starfire Owner's Manual

OWNERS

TECHNICAL

MANUAL

$3

:50 '

INTRODUCTION

The

following

pages

of

this manual cover one

of

the most

sophisticated high performance snowmobiles on the market

today.

The

1973

TX

Starfire snowmobile - - - "a

finely

tuned,

quality

performance machine that

is

backed

by

a

heritage

of

leadership which

is

unique in the

industry."

The

1973

TX

Starfire and this manual are the results

of

the

Polaris

Race

Team

joining

forces

with

the

newly

formed

"Polaris Competitive Snowmobile Engineering Department". This manual covers

not

only

technical and service

information

but

a certain

amount

of

theory related

to

the contents enclosed.

All

information

and specifications are

printed

to

the best

of

our

knowledge

at

this time. "Changes and adjustments usually

are required

after

meeting

our

competition and

to

suit

various

track

conditions"

so

there

can

and

will

be some

changes

to

this manual.

To

enable

us

to

send this new

information

to

you

it

is

essential

that

the tear-out card in the back

of

this manual

be

filled

out

in

full

and mailed

to

Polaris.

Good luck and successful racing

to

all

of

you.

Competitive Snowmobile

Eng.

Dept.

POLARIS A Textron Company Roseau, Minnesota 56751

TABLE

OF

CONTENTS

General Dimensions . . .

Specifications . . . . .

Controls

And

Instruments .

Brakes . . . .

Gearing . . . . .

Chaincase

Oil Level .

Clutch Alignment

And

Center Distance

Steering . . . .

Tracks

And

Studding

Track

Alignment

And

Tension

Track

Alignment

. Track Removal Suspension . Drive Belt . . Drive Clutch . Clutch

Specifications Trouble Shooting - Drive Clutch

Driven Clutch . . . . . . .

TX

Starflame Engines . . . .

TX

Starflame Engine Specifications.

General Engine

Information

And

Maintenance

TX

Starflame Torque Patterns

Twin

Cylinder

Ignition

. . . . . . .

Kokusan-Denki

Breakerless Flywheel . .

Trouble

Shooting-

Twin

Cylinder

Ignition

Circuit

Checking Of CDI

Unit

By

Tester .

Three Cylinder

Ignition

. . . . . . .

Trouble

Shooting

Of

Three Cylinder

Ignition

Circuit

Checking

Of

CDI

Unit

By

Tester

Machine Wiring Diagram . . . .

Mikuni

Carburetors

And

Fuel Pump

Fuel Pump . . . . . . . . .

Carburetors Keihin Carburetors - Schematic

View

.

Service Instructions . . . . . . .

Float Level . . . . . . . . . .

Trouble

Shooting-

Keihin

RD38

And

RD50 Warranty Safety

.7 .8 .9

10.

11

12-

13 14 15 16

17-

18 19

20 22-24 25-26

27 28-30

31

32

33 34-35

36 37-39

40

41 42-46 48-49

50 51-60 62-63

64

65

66 67-68 69-77

78 79-82

83 84-85

86

87

GENERAL DIMENSIONS

Below

are

the general dimensions

of

the 1973

TX

Starfire. You

will

note

that

the styling and

some

important dimensions

have

changed.

These

changes

were

made

to

further improve the

handling characteristi

cs

of

this machine.

As

compared

to

the 1972 Polaris

TX

Starfire the

'73

chassis

is

6"

longer (Note

'A').

This

is

required

for

improved turning

and

handling. The ski stance

for

'73

is

3"

wider

for

better

stability (Note 'B') and more precise steering control

on

tight

corners.

7

p--

l

SPECIFICATIONS

The specifications on this

page

are

very general. More detailed

specifications

will

be

covered under

each

separate item.

ITEM

294

335 439

649

TX

Starflame

Number

of

Cylinders

2 2 3

Engine

Bore

58mm 62mm

58mm 67.75mm

Stroke 55.

6mm

55.6mm

55.5mm

60mm

Carburetor

Mikuni

Keihin Keihin

VM34 VM36

RD38

RD50

Displacement

293.79cc

335.7cc 439.9cc 648.8cc

Material

Aircraft Aluminum

Chassis

Overall Length

106" 106" 106"

106"

Overall

Width

37"

Overall Height

34" 34" 34"

34"

Weight

Track Track Width

15"

15

"

15"

Track Material

Rubber

with

machine riveted cleats

or

molded rubber

Standard gear ratio

13.35

16.39

16.35

17.35

Ignition Type

Kokusan

Capacitor

Discharge

Timing

Specs

( 5000 3.5mmBTDC 3.5mmBTDC

3.5mmBTDC 3.75mmBTDC

RPM)

26"

*Spark

Plugs

(Champion) N57 N57 N57

N57

Plug Gap

.018"

Fuel System

Tank Capacity 3.5

U.S.

Gal

. 3.5

U.S.

G•l.

3.5

U.S.

Gal. 3.5

U.S.

Gal.

Fuel

Type Premium, not less than

98

octane

Mixing Ratio

16:

1

Four

gallons

to

one quart

Brakes

Type Hydraulic

Disc

Brakes

Disc Diameter

7l4"

Fluid Type

Automotive

Hydraulic Brake Fluid

Suspension

Type

Equaliberator Slide Rail

*Machines come equipped

from

factory

with

Champion N59G

Spark plugs.

Use

these plugs

for

break-in

ONLY.

After

break-

in, install N57 Champion

Spark

Plugs.

8

CONTROLS

AND

INSTRUMENTS

The controls

and

instruments on

your

1973

TX

Starfire

are

located in the position we feel

is

most convenient.

We

do

recommend, however,

that

each person relocate his

or

her

throttle

and brake levers

to

positions better suiting the

individual's driving style

for

maximum control and safety.

WARNING:

The brake lever

is

part

of

the master cylinder

assembly and

will

not

function

properly

if

rotated more than 10 ° up

or

down

from

the

factory

assembly position.

ft

____

,

®-

...

I

1.

Shut-off Switch

5. Tachometer

2. Gas Cap

6.

Tether

Switch

3. Master Cylinder

7. Handle Bar Padding

4. Brake

Control

8.

Throttle Control

9

BRAKES

As

performance

and

the new design

are

at the ultimate on the

'73

TX

Starfire,

it

was

necessary

to

incorporate a different

hydraulic brake system. This

is

the Kelsey Hayes caliper

system

with

a 7

3/4"

diameter disc

and

the standard Polaris

master cylinder.

This system

is

very simple,

but

does

need

to

be

inspected

periodically.

Before

each

race,

we

strongly recommend

that

the following

be

inspected:

1.

Check brake

hoses

and fittings

for

signs

of

abrasion and

leakage.

2.

Check

fluid

level in master cylinder. If low,

use

ONLY

an

automotive

type

hydraulic disc brake

fluid.

This

is

available

from

automotive supply

houses

or

from

Polaris.

Do

not

use

hydraulic oil, mineral oil, aviation fluids,

or

any

red

fluids.

3.

Check brake handle

for

a solid 'squeeze'.

If

action feels

spongy, air

has

possibly entered the system

and

the

system

will

have

to

be

bled.

10

BRAKES (Can't.)

Bleeding the Hydraulic Brake System

To bleed the system, the following method should

be

followed.

1.

Remove master cylinder reservoir cover and

fill

to

top

lip

of

reservoir. Refer

to

Fig.

1,

Item A.

2.

Slip rubber tube over ball

of

top

bleeder valve

to

direct

fluid

away

from

painted surfaces. Refer

to

Fig. 2, Item

A.

3.

Squeeze brake lever (slowly) a

full

stroke and hold;

to

release

air through tube, unscrew

top

bleeder valve

3/4

turn. Close bleeder valve, then

release

brake lever. Repeat

above procedure

until

fluid

flows

from

bleeder valve in a

solid stream

that

is

free

of

air. Check master cylinder

res-

ervoir periodically

to

make

sure

that

it

contains fluid.

Fig. 1

Fig. 2

11

GEARING

The selection

of

the proper chain sprocket ratios

are

essential

to

achieve maximum performance. Track condition, snow con-

ditions, temperatures, weather, altitude, driver weight, etc.

are

some

of

the factors which must

be

considered

in

the selection

of

the proper ratio.

Your 1973

TX

Starfire performance machine comes equipped

with

the

following

sprocket ratios:

Machine

294 335 440

650

Gears

13-35 16-39 16-35 17-35 Chain pitch Optional sprockets

are

as

follows:

Number

of

teeth Polaris Part Number 12 3221020 13 3221012 14 3221023 15 3221008 16 3221021 17

3221009

19

3221010

21

3222008 23 3222017 35 3222021 39 3222026 41

3222025

The

following

sprocket

to

gear

ratio chart

wi

II

be

a great benefit

to

you when selecting the proper combination.

12

Sprocket Combination

23

-35 21 -35 23-39 23-41 19-35 21-39

21 -41

17-35

(650)

19-39

19-41 16-35

(440) 17-39 15-35 17-41 16-39

(335) 14-35 16-41 15-39 13-35

(294) 15-41 14

-39 12-35 14-41 13-39 13-41 12-

39

12-41

....

l:

'El

I

II\

\v

....

3:

;::;;

..J

GEARING

Ratio Chain

Pitch

1.52

66

1.67

64

1.70

68

1.78

68

1.84

64

1.86

66

1.95

68

2.06

62

2.05

66

2.16

66

2.19

62

2.30

64

2.32

62

2.41

66

2.42

64

2.50

62

2.56

66

2.60

64

2.70

60

2.73

66

2.79

64

2.91

60

2.93

64

3.00

64

3.18

64

3.25

62

3.42

64

13

Chain Part

Number

3224020

3224019

3224~21

3224021

3224019 3224020 3224021 3224018 3224020 3224020 3224018 3224019 3224018 3224020 3224019 3224018 3224020 3224019 3224017 3224020 3224019 3224017 3224019 3224019 3224019 3224018 3224019

CHAINCASE

01 L LEVEL

The drive chain

within

this model

is

constantly immersed in

oil. Maintain

oil

level

with

No. 10 weight non-detergent engine

oil.

We

recommend

that

chaincase

oil

be

checked on a weekly

basis.

The proper amount

of

oil

is % pint

(237cc) in

an

empty

case.

DRIVE

CHAIN

TENSION

To

maintain lasting chain and sprocket life the drive chain

tension

is

very important. Chain tension should

be

checked on

a weekly

basis.

The proper tension

is

%" free play

at

driven

sheave

rim

(see

diagram).

To

tighten chain loosen lock

nut

and

turn

tightner

bolt

clockwise and lock.

To

loosen reverse above

procedure.

14

CLUTCH

ALIGNMENT

AND

CENTER DISTANCE

Due

to

the lower center

of

gravity location

of

the engine the

center distance between the center

of

the crankshaft and the

center

of

the jackshaft

is

not

adjustable. Should the distance

change,

it

will

be

necessary

to

inspect the mounts and mounting

bolts

for

proper tightness,

distortion,

or

breakage.

+ 1

/8"

The proper center distance

is

10~"

-1/4".

+1

/32"

The

sheave

offset

is

5/8"

-0"

. This

is

adjusted by either

adding

or

removing the spacer washers

from

behind the driven

clutch.

After

alignment, you should very carefully start the engine,

accelerate the machine

to

get the belt

to

the

top

of

the drive

clutch and make certain the belt

is

running in a straight line.

Clutch

center distance and alignment should

be

checked

0 weekly

or

immediately after a

belt

is

replaced.

WARNING:

Do

not

rev engine above level required

to

get

belt

to

top

of

drive clutch when in unloaded

condition

(approximately

7500

RPM). Stay

clear

of

all moving parts.

15

STEERING

Your

1973

TX

Starfire performance snowmobile comes equip-

ped

with

carbide ski

skags

for

more precise high

speed

hand-

ling. These new

skags

exert a greater

amount

of

force

not

only

on the

skag

itself

but

also on the entire steering assembly.

We

recommend

that

to

achieve maximum life

from

the

skag

that

you tack weld this

skag

to

the ski board in

addition

to

the bolts.

For

your

own safety and

reliability,

it

is

important

that

weekly

all

nuts, bolts, and tie rod ends

be

checked

for

looseness or stress damage. Ski

tow-in

should

be

checked at the

same

time. Skis should

be

parallel when in the straight ahead position

to

each other

to

3/8"

toe-out.

WARNING: Never operate

your

1973 Starfire

with

skis

toed-in

or

your

'Polaris may

set

you free.'

If

adjustment

is

required:

1.

Release

tie rod end locknuts.

2.

Rotate tie rod

until

alignment

is

correct.

3.

Tighten locknuts.

4.

In the event

that

any

of

these items are damaged

or

overstressed,

we

recommend replacement

of

com-

plete tie rod and rod end bearings in

sets.

16

31

+ 3/8

- 0

TRACKS AND STUDDING

Your 1973

TX

Starfire performance snowmobile wi.

l'l

come

equipped

with

either the performance cleated track·

or

the

long distance molded rubber track,

as

ordered.

The performance

cleated track

is

equipped

with

nine (9)

'Talonic Cleats', eighteen (18) Guide Cleats and ten (10) Standard Cleats.

Ice

studs

are

not

necessary.

Although the nine (9) Talonic Cleats

are

sufficient

for

most

conditions,

it

will

be

necessary

to

add

or

remove some

of

these cleats depending on the track and conditions you are running on.

IMPORTANT!!

After

every day

of

racing check track mate-

rial, cleats, and rivets

for

damage

or

break-

age;

replacing when

necessary.

WARNING: The rivets

used

for

holding on the cleats on

Starfire

mode l

are

of

a

different

alloy

than

those

used

on all other Polaris models.

It

is

essential

that

when installing new rivets

to

use

the ones specified

for

the

TX

Starfire.

These

are

available fr

om

Polaris

by

ordering part

number

7621430.

IYET

#7621430

17

TRACKS AND STUDDING (Con't.)

The long distance molded rubber track

is

a proven track

for

your long distance endurance

races

and

is

equally good on the

oval. This track comes

without

ice studs installed

because

many

people

have

their own

ideas

of

which stud

is

the best. How-

ever,

we do recommend the carbide tipped

ice

stud available

from:

Special Sports Products Corporation

1573 Pinecrest Drive

Cario, Michigan 48723

Roetin

Industries 24 Saginaw Drive Rochester, New

York

14623

and many other

sources.

The recommended pattern

for

studding this track

is

shown in

the diagram

below.

18

TRACK

ALIGNMENT

AND

TENSION

(Both

Tracks)

Proper track tension must

be

maintained

to

attain maximum

performance

from

your

TX

Starfire machine.

If

the track

is

too

loose,

it

will

have

a tendency

to

chatter

as

the cleats

or

studs

scrape the inside

top

of

the tunnel.

If

it

is

too

tight,

a great

amount

of

pressure

will

be

applied

to

the slide rail wear bars,

resulting in

friction

drag and

loss

of

performance.

Improper alignment

will

cause

the track

to

run against one

side

of

the slide rail

or

the

other

causing dragging action and

also resulting in poor performance. The proper tension

is

accomplished

by

the

following:

1.

Lift

rear

of

machine and support

it

off

the ground.

2.

Allow

the slide rail

to

apply pressure on track.

3.

Track should have

3/16"

to 1 /4"

of

gap

between

track and

lowest

point

of

slide rail at

midpoint

of

the track.

4.

Adjust

to

proper tension

by

either loosening

or

tight-

ening the adjuster

bolts.

NOTE:

Track tension and alignment are inter-related. Do

not

adjust one

without

adjusting the other.

3/is"to

1/4''

ADJUSTER

BOLT

19

TRACK ALIGNMENT

After

track tension

has

been

corrected, pull track through a

couple

of

revolutions. Check

to

see

that

track

is

well-centered

between tunnel and slide rail.

To

adjust, loosen lock

nut

and

tighten adjuster

bolt

on

side

where track

is

closest

to

frame.

Tighten

lock

nut

and recheck alignment.

WARNING : Always stay clear

of

moving parts when per-

forming

such checks and adjustments.

EQUAL

DISTANCE

20

NOTES

21

TRACK

REMOVAL

Your

1973

TX

Starfire

is

equipped

with a quick

change

front

drive shaft. This unique system

was

developed

for

two

very

important

reasons:

1.

It

is

extremely fast

to

change tracks

...

approxi -

mately ten minutes

from

start

to

finish.

2.

The chaincase, gearing, and driven

clutch

do

not

have

to

be

removed.

Without

having

to

remove any

of

these items,

your

clutch alignment and center

distance

will

not

change.

To remove

track:

(See

opposite

page)

NOTE:

Leave

chaincase

as

is!

It

is

not

necessary

to

remove

cover, chain

or

gears.

1.

Remove slide rail.

2. Loosen

front

drive shaft bearing lock collar.

3.

Loosen

only

the

bottom

two

(2) bearing flangette

supporting bolts (do

not

remove).

4.

Slide

front

shaft

from

splines in stationary hub

mounted

to

the chaincase.

5.

Pivot

front

drive shaft and bearing in flangette.

6.

Slide

front

shaft

from

bearing and remove shaft and

track.

7.

To

reinstall, reverse the above procedure.

8.

Check track alignment and tension.

NOTE:

When tightening bearing lock collar,

tighten

with

the

rotation

of

the

front

drive shaft.

22

TRACK

REMOVAL

(Con't

.)

3.

LOOSEN

BOTTOM

SUPPORT

BOLTS

2.

LOOSEN

LOCK

COLLAR

4.

SLIDE

SHAFT

INTO

BEARING

23

TRACK

REMOVAL

(Con't.)

When reinstalling slide rail,

be

certain

that

you

use

the proper

mounting

holes in

the

tunnel.

(See

diagram)

NOTES

PROPER

MOUNTING

HOLE

THIS

HOLE

MAY

BE

USED

IF

LESS

SKI

PRESSURE

IS

DESIRED

24

PROPER

MOUNTING

HOLE

SUSPENSION

The 1973

TX

Starfire

is

equipped

with

a redesigned slide rail

system. This suspension

is

basically the

same

as

used

on other

Polaris models. There

are

two

(2)

major adjustments

on

this

system. They

are

as

follows:

1.

Rear

springs

have

two

(2)

adjustments

for

driver weight.

For drivers between 100 - 160 pounds,

put

the springs

in the

lowest position;

for

drivers 160 pounds and over,

put

the springs in the

top

position (refer

to

item no. 1).

2.

Front

springs

are

adjustable by tightening or loosening

the adjustment nuts on the springs. Adjust these

for

track

or

surface condition

by

applying

or

decreasing

the

amount

of

pressure on the

front

torque arm (refer

to

item no. 2).

ITEM

#2

ITEM

#1

25

SUSPENSION (Con't.)

Before attending

your

first

race,

we

suggest

that

you

try

all

adjustments and

different

positions

to

attain the best ride and

handling characteristics

for

your

style

of

riding.

Slide rails should

be

visually inspected weekly

for

worn

or

dam-

aged

parts;

if

worn

or

damaged,

they

must

be

replaced

prior

to

continued

use.

WARNING: Never operate machine on gravel,

dirt,

or

glare

ice

without

snow

for

long periods

of

time,

as

it

is

damaging

to

the slide rail and track assemblies.

NOTES:

26

DRIVE

BELT

The drive belt

is

used

to

transfer power

from

the engine

to

the

track through the drive and driven

clutches. A great amount

of

torque and surface

speed

are

put

through the belt.

Before

each

and every

race

or

heat

race,

remove belt and in-

spect

for

distortion,

wear,

or

fatigue.

If

it

is

bad, replace

with

a

new

belt.

NOTE:

Drive belts must

be

kept

free

of

dirt,

grease,

oil, and

moisture

both

when in

use

and in storage.

BELT

REMOVAL

AND

INSTALLATION

(See

Diagram)

1.

With hood

off,

open the driven

sheave

by

pushing and

twisting.

2.

Pull

bottom

of

belt in toward inside

of

driven pulley. Slip

loose belt

over

top

edge

of

sheave.

3.

Remove old

belt

from

drive

sheave.

4.

To

install new belt, reverse procedure, being careful

not

to

damage belt and keeping

it

free

of

moisture,

dirt,

etc.

WARNING:

Never start

or

run engine

with

belt removed.

27

DRIVE

CLUTCH

THE

DRIVE

CLUTCH

ON

YOUR 1973

TX

STARFIRE

IS

WITHOUT A DOUBT THE SECOND MOST

IMPORTANT

ITEM

ON

YOUR MACHINE

AFTER

THE ENGINE.

It

is

like

the brain in the human body - -

if

the human brain

is

not

functioning properly, the

body

is

not

working properly. The

clutch

is

the

same.

If

it

doesn't

work

properly, neither

does

your machine.

This

clutch

is

an

RPM

and

torque

sensing

unit

designed

to

transfer the maximum amount

of

horsepower

from

the engine

to

the ground. This

is

accomplished

by

weights and a spring

inside the

unit

reacting

to

overcome the centrifugal force

applied

to

it

from

the engine.

The spring and weights work in combination. The spring resists the force

of

the weights mainly

for

engagement

but

assisting

through the

complete shift pattern.

If

the weights are

too

light

(not heavy enough), the clutch

will

give you a

'fair'

engagement.

Immediately the engine

will

obtain very high RPM,

but

the

belt

will

not

go

into

high

gear

(top

of

the clutch).

(See

diagram no. 1).

RPM

Diagram

#1

1o,ooo

r

8,

000

./

6,000 4,0

00

2,000

28

DRIVE

CLUTCH (Con't.)

If

the weights

are

too

heavy

(too

much weight), you

will

have

a good engagement,

the

engine RPM's

will

be

low

and drive

the

clutch

into

high gear; then the RPM's

will

gradually

increase.

(See

diagram no. 2).

Diagram

#2

RPM

10,0

00 8,000 6,000 4,000

2,000

NOTES

29

DRIVE

CLUTCH (Con't.)

If

weights and spring are matched properly,

the

engagement

speed

will

be

correct and engine

RPM

will

immediately

go

into

desired

RPM

and stay there on

both

up shifting and

down

shifting.

(See

diagram no. 3).

Diagram

#3

RPM

1

0,0

00

8,000 6,000 4,000

2,000

NOTE:

It

is

essential

that

the drive clutch

be

disassembled

weekly

and cleaned. Lubricate all moving parts

with

a light

coat

of

machine oil.

NOTE: Specification sheet on

page

31

for

proper

RPM

setting

for

spring and weights.

30

---...

CLUTCH

SPECIFICATIONS

Clutch

294

335

440

650

Part Number

1321215

1321216 1321217

1321218

Springs

Part Number

7041036

7041036 7041036 7041036

Spring dia. (wire size) .

170"

.

170"

.

170"

.

170"

Spring

I.

D.

(color)

Dayglow Pink

Weights

Part Number

5630067

5630091

5630065

5630066

Weight

in

grams

34

.5

36

40 44

Weight I. D.

L

R

J

K

(Letter identification)

Enaagement

S~eed

RPM

6,000-7,000 6,000-7,000

6,000-7,000

6,000

-7,00(

Maximum

Horse~ower

(RPM where clutch should run) 9,000* 9,000*

9,000*

Optional Weights

Part Number

5630090

5630089

5630068 5630064

Weight

of

Weight

in

grams

Q;38g

p;

42g

M;47g

H;

50g

5630096

5630080

T ; 32g

N;

54g

Optional Springs

.179"

.192" .192"

Part Number

7041040

7041037

Dayglow Orange

Dayglow Yellow

NOTE: Weights and springs shown above may

have

to

be

changed

from

standard

production

depending

on

geographical

area,

weather, track conditions,

or

if

engine

is

altered

from

original equipment.

Machines running

at

elevations in

excess

of

6,500 feet above

sea

level

will

most

likely

have

to

use

original equipment.

*

With

engine warmed

up

31

TROUBLE SHOOTING -

DRIVE

CLUTCH

Problem

Clutch

engagement

too

low

Clutch

engagement

too

high

Clutch weight

too

heavy

or

RPM

too

low

Clutch

weight

too

light

or

RPM

too

high Grease,

oil,

or

rubber

on

sheaves

Lightest weight

too

heavy

or

no weight available between the two

weights

Probable

Cause

and

Fix

Spring

has

lost its tension

Check height

with

new spring,

re-

place

if

necessary

Spring

too

heavy-

replace

with

lighter

dia. spring

OR

Moving surfaces

dirty

- clean and oi I

Replace

weight

with

next lighter weight Check engine over

for

possible loss

of

horsepower

Check

clutch rollers

or

weights

for

possible seizure Replace

with

Find

cause

and

sand

sheaves

with

No.

220

grit

sandpaper

Use

the heaviest weight tried and

trim

as

in diagram below.

Trim

in

.020"

graduations at a time.

NOTE: When grinding weights

be

sure

that

when finished all three

weights weigh the

same

~

.2 grams.

REMOVE

MATERIAL

.020

32

DRIVEN

CLUTCH

The driven clutch

for

the 1973

TX

Starfire

has

been

complete-

ly

redesigned and tested.

It

is

made

from

aluminum

alloy

die casting

for

better heat trans-

fer

from

the belt, better balance, and

less

maintenance.

As

stated above, this clutch

is

relatively maintenance free.

We

'

suggest

visual inspection weekly. Lubrication

is

necessary

be-

tween the helix hub

and

the stationary shaft on a weekly

basis.

Recommended lube

is

either a light coating

of

grease

or anti-

seize

compound.

Correct tension

of

the driven clutch spring

is

1/3

turn

wind

-up

(counter-clockwise).

33

TX

STARFLAME ENGINES

Twin

Cylinder

Three Cylinder

EC

29PR 294cc

E

C 43P R 439cc

E

C 34P R 335cc

EC

65PR

649cc

Your Polaris

TX

Starfire snowmobile

is

equipped

with a de-

pendable, high-performance

TX

Starflarne

fully

modified two-

cycle engine. Treat

it

right

...

give

it

reasonable

care.

The

first step

is

to

have

a basic comprehension

of

the mechanics

involved in its operation. Understanding

your

two-cycle engine

and how

it

functions

will

enable you

to

better maintain your

engine,

resulting in longer and better performance and life at

less

cost

to

you.

A basic component

of

the

TX

Starflame two-cycle engine

is

the piston.

When

the piston

moves

upward in the cylinder

(1st stroke),

it

draws fuel into the crankcase while

also

com-

pressing

fuel in the combustion chamber. The spark plug then

ignites the

fuel, which expands and forces the piston downward.

The down-stroke provides the power which turns the crank-

shaft.

It

also

compresses

fuel in the crankcase,

exposes

the trans-

fer ports in the

cylinder wall and

releases a new

supply

of

fuel through the ports and into the combustion chamber. This forces the burned

gases

out

through the exhaust ports.

When

you realize

that

at 6,000 RPM, this happens 100 times a

second, you

can

appreciate the importance

of

proper lubrica-

tion, fuel mixture,

and

carburetor adjustments.

34

TX

STARFLAME ENGINES (Con't.)

Oil provides the

only

lubrication

your

engine

gets.

Keep

in

mind

these recommendations:

1.

Use

a good

grade

of

both

oil

and gasoline

...

gasoline

not

less

than 98% octane.

2.

Always

mix

them in proper proportions, 16:1

--thorough-

ly--

and in a clean container.

3.

Keep surplus fuel

tightly

capped

to

prevent evaporation,

loss

of

volatility

and power.

Too

little

oil

means

inadequate lubrication;

too

much

oil

means

spark plug fouling, rapid carbonization, and over-heated pistons,

all which may

lead

to

engine damage and costly repairs.

The carburetor feeds the gas-oil

mixture

to

the engine, mixing

the fuel and air

to

obtain the correct volatile mixture, thus

providing fuel

for

combustion,

the

lubricant, and a coolant

for

internal surfaces.

NOTES:

35

TX

STARFLAME ENGINE SPECIFICATIONS

EC29

PR

EC34

PR

EC43

PR

EC65

PR

295cc 340cc 440cc 650cc

Number

of

cylinders

2 2 3

3

Bore

58mm

62mm

58mm

67.75

mm

Stroke

55.6

mm

55.6mm 55.5mm

60.0

mm Displacement Cubic

Centimeters 293.79 cc 335.7 cc 439.9 cc 648.8 cc

Cubic Inches 17.941 Cl 20.504 Cl

26.911

Cl

39.631 Cl

Compression Ratio -

Effective 7.1 : 1

7.0:

1

7.1:

1

6.35:

1 Cylinder Head Volume

CC

15.5 cc 18.5 cc

15.5 cc 22.75 cc

Connecting Rod

Material

Chromium

moly

steel

Connecting Rod Brg.

Type

Needle Bearing

Cylinder Material Large

fin

aluminum

casting

w/chrome

liner

Number

of

Main Bearings

5 5

7

Type

of

Main Bearings

Ball

Ball Ball Ball

Piston

Type

High silicone

aluminum

die-cast

Piston

Clearance (Max.)

.005"

.0055"

.005"

.006"

Piston Ring

Type

One Plain

Type

Ring

Per

Cylinder

Ring Material

Steel

Ring end gap (Max.)

.015" .018" .015" .021" Port Heights (Dimensions when

port

begins

to

open)

Exhaust

28.6mm 29.0mm

28.6

mm

31.0mm

Intake 91.8

mm

91.8

mm

91.8

mm

99.0mm

Transfers

43.0

mm

43.0

mm

43.0

mm

47.0

mm

Port Widths (Measured

in

Circumference

of

Cylinder)

Exhaust

37.0mm

39.6

mm

37.0

mm

42.0mm

Cooling Free

Air

Free

Air

Free

Air

Free

Air

36

TX

STARFLAME

ENGINE

GENERAL

INFORMATION

AND

MAINTENANCE

The

TX

Starflame engine

for

'73

has

been

completely

re-

designed

to

provide a 'winning' amount

of

horsepower and

sustain the

stresses

created

by

competitive

use.

It

is

all new

from

the

large

fins on the cylinder

head,

cylinder

and

crank-

case

to

chrome bore cylinders and tougher crankshaft

with

either 5

or

7 ball

type

bearings (Note specification sheet). The

goal

we

set

for

ourselves

was

to

get 160 Hp per liter and

we

did it. Your

TX

Starflame engine

is

a completely

modified

engine and

should

be

treated

as

such. The

following

items should

be

followed

if

you expect

to

receive maximum dependability

and power:

1.

Break-in, new engines - -

We

strongly recommend a

break-in period

of

30 minutes operating time. During the

first

15

minutes, maximum

throttle

should

not

exceed 4,000

RPM

with

no

load. The second

15

minute break-in period should

not

exceed 7,000

RPM

(1

/4

throttle).

During this break-in time,

use

N59G spark plugs.

After

break-in,

use

Champion N57 spark

plugs.

2.

Use

a good grade air-cooled

two

cycle engine oil and

premium

gas

of

not

less

than 98% octane mixed 16 : 1 (one

quart

of

oil

to

four

gallons

of

gas).

3.

After

one

to

two

hours

of

operating cylinder

head

retaining nuts should

be

torqued

to

13

ft.

lbs.

with

engine

COLD and weekly thereafter. (Note: refer

to

torque data,

page

40.)

4.

Keep engine and engine compartment clean. Engines

with

dirt,

grease,

and

oil

coating

will

not

dissipate heat properly.

A

clean

engine and engine compartment

will

also aid in the

location

of

a problem

if

it

should arise.

37

TX

STARFLAME ENGINE (Con't.)

5.

Engines should

be

checked over weekly. This in-

cludes: check all nuts and bolts, pull exhaust pipes

and

check

the piston rings

for

tension and the piston

for

possible seizure.

6.

Piston rings - Every

four

to

five weeks

or

every

2Y:!

to

3 hours, we

suggest

that

you install new piston rings. Do

not

hone the 1973 Starflame cylinders,

as

you

will

damage the

chrome

liner. A break-in period

of

10-15 minutes should

be

followed

as

per item no. 1 after re-ringing.

7.

Engine overhaul - The

TX

Starfire engines

are

very

simple

to

dismantle and reassemble. The

only

special tools

that

are

necessary are:

A. Piston pin

puller-

Part No. 2870202

B.

Clutch

puller-

Part No.

2870130

C.

Flywheel

puller-

Part No. 2870159

D.

Pocket

knife

NOTES:

38

TX

STARFLAME ENGINE (Con't.)

The pocket knife

is

to

remove the new

'Spirolox'

wrist

re-

tainer

(see

diagram).

To remove the

'Spirolox',

take a suitable pocket

knife

blade

and

pry

out

on the

lip

(point no. 1) and unwind lock

from

piston . To replace, put

(point

no. 2)

into

snap

ring groove and

spiral

into

pin bore ring groove.

NOTE:

These

retainers should

be

replaced

with

new retainers

after

they

have

been

removed.

When

reassembling crankcase halves,

be

certain

that

both

halves

are

completely

clean

and apply a

thin

coat

of

sealer.

8. Ignition

timing-

see

ignition section.

1

39

TX

STARFLAME TORQUE PATTERNS

CD

®

CD

®CD

0

PTO

CYLINDER

HEAD

TWIN

CYLINDER

CRANKCASE

14 - 17 Ft.

Lbs.

on new

head

gasket 14 - 17 Ft. Lbs.

13 - 15 Ft.

Lbs.

on

used

head

gasket 24 - 28 Ft.

Lbs. -PTO

®

CD

®

@

0

CD

® ®

®

0

CD

(j)

®

CD

®

PTO

THREE

CYLINDER

CRANKCASE

14-17

Ft.

Lbs.

24 - 28 Ft.

Lbs. -PTO

40

TWIN CYLINDER IGNITION

CRANKSHAFT

C.O.

IGNITION UNIT

IGNITION COIL

41

KOKUSAN-DENKI

BREAKER

LESS

FLYWHEEL

MAGNETO

TYPE

GK

352

1.

Specification

Rotation: clockwise Number

of

sparks per revolution: twice in

180°

alternate sequences

Range

of

revolution:

300-

8000

RPM

Max. 10,000 RPM, 3 minutes

Spark length: measured

by

using three needle

gap

at

300

RPM

....

9 mm

or

more

at

5,000

RPM

..

15 mm and

less

Lighting

output:

AC

12V,

75W

at

4500

RPM

(to

divide

equally

into

two

lead wires)

0

Automatic

timing

advancer: advance 12 approx. at

300

RPM

and onward (electrically automatic advancer)

Weight: 4.5 kg (including ring

gear)

Moment

of

inertia: 219

kg-

cm2 (including ring

gear)

2.

Construction

2.1

Outline

This GK 352

type

flywheel magneto applys a new control

unit

called

"Capacitor

Discharge

Igniter",

which

works

alike

with

contact breakers

of

ordinary

flywheel magnetos.

Thus, this flywheel magneto does

not

use

any contact

breakers and conventional condensers. GK

352

works

as

electric power source

for

said

CDI unit.

Hundreds voltage generated

by

it

is

stored in a primary

condenser and

abruptly

discharged

to

a primary coil

of

an

ignition coil in a

timed

relation

with

an

engine operation. Then, a secondary coil generates high voltage electricity for

igniting

gaseous

air.

42

KOKUSAN-DENKI

BREAKERLESS FLYWHEEL

MAGNETO TYPE

GK

352 (Con't.)

2.2 Flywheel The flywheel

is

of

steel plate

press

-formed into a bowl

shape.

Inside

are

BaFerrite magnets

with

coesive

power

being fixed

by

screws

and adhesive plastics.

2.3

Stator Plate

On

an

aluminum die

cast

alloy plate

are

screwed

face

to

face

an

exciting coil and a pulser coil in

two

layers and

a lighting

coil. The exciting coil generates electricity

to

charge

it

to

the primary condenser

and

the pulser coil

sends

signal

voltage

to

CDI

unit

at the time

to

spark in

engine operation, thereby the ignition

coil generates high

voltage.

2.4

CDI

Unit

CDI

unit

has

an

outer-appearance

as

shown in drawing.

In the

steel

case

are

incorporated diodes and thyristers,

etc. and

to

provide a shock

proof

construction the whole

parts

are

molded

with

polyester resin.

2.5

Ignition Coil

3.

This ignition coil

is

of

instantaneous sparking system and

is

also

molded

with

polyester

resin

for

proving wet-proof

and

against breakdown construction.

Two

ends

of

a

secondary

coil

are

led

outward .

Mounting

and

Dismounting

3.1

Mounting

(1) To install the stator onto

an

engine body

be

careful

not

to

leave

any dust

or

iron chips between the

fitting

surfaces

of

the stator and the stator holding surfaces

of

engine. Then position the

fitting

screw holes right in the

center

of

two

elongated holes

of

the stator and then screw.

43

KOKUSAN-DENKI

BREAKERLESS

FLYWHEEL

MAGNETO TYPE

GK

352 (Con't.)

(2) Next

fit

the flywheel

to

the engine shaft.

But

strongly

magnetized, the flywheel

is

apt

to

cling iron chips and

scraps

so

be

sure

no chips

are

clinging

to

it

and

clean the

shaft and tapered hole

of

the flywheel.

(3) To screw the flywheel

to

the shaft, screw

it

with

stipulated

screw

torque

60ft.

lbs.

(4)

Mounting

of

CDI

unit

and Ignition coil

Fit

the CDI

unit

and ignition coil at prescribed position.

Then checking the color

of

lead

wires

to

connect, connect

the couplers.

When

CDI

unit

and ignition coil

are

not

connected

firmly

it

is

likely

to

damage

the unit.

So

do

not

start the engine leaving the

unit

disconnected.

(5) Checking

of

Sparking Time

Since this igniter

is

of

breakerless system, sparking

time

rarely

goes

out

of

order. But,

if

necessary,

use

a strobe

light

for

checking.

If

the timing mark

of

a fan and the

upper timing mark

of

the fan cover rear constitute a line

a

7,000

RPM,

timing

is

in well adjusted condition or

3.5 mm (

26°) BTDC at 5,000

RPM.

When

sparking

angular

is

off

the prescribed degree,

measure

the

off

angle

and slide the stator equal

degree

by

using the elongated

holes. Then check

it

again.

3.2 Dismount (

1)

To remove the flywheel

from

the shaft unscrew the

hexagon nut.

In

this

case,

however,

use

a specified

de-

taching

tool

and do

not

force open

by

a driver

or

knock

with

a hammer.

Use

Polaris flywheel puller No. 2870159.

4.

Maintenance Normal operation

of

an

engine indicates

that

sparks

obtained

from

magneto

is

excellent and spark timing

is

44

KOKUSAN-DENKI BREAKERLESS FLYWHEEL

MAGNETO TYPE GK 352 (Can't.)

also remained in normal condition.

So,

there

is

no

necessity

to

conduct any adjusting

work

on

the

magneto

if

care

is

given

to

the following points:

4.1

Removing

of

dust and

oil

4.2 Checking

of

connections

of

leads

and couplers

4.3 Checking

of

screw loosening

5.

Inspection and Overhaul

5.1

Flywheel

In ordinary operation no repairs

are

needed.

5.2 Stator In ordinary operation no repairs

are

needed.

But

when

engines

are

out

of

order

or

do

not

run

or

when a secondary

coil does

not

generate high voltage check the

following points: (1) Exciting Coil Using a tester (Ohm meter) check the

continuity

between

coil plate and

lead

wire (black).

If

resistance measures 23

ohms

it

is

normal.

(2) Pulser Coil

Using a tester check insulation resistance between coil

plate and a

lead

wire

(brown).

If

resistance

measures

co

,

it

is

in normal condition.

continuity

between

lead

wire (brown) and lead

wire

(plural-

black and white).

Normal resistance

is

53 ohms. (3) Lighting Coil Breaking down

of

coils

is

not

likely

to

occur

so

check

the state

of

soldering and couplers. Test

continuity

be-

tween the stater and the

lead

wire (yellow). Normal

re-

sistance

is

0.35

to

0.45 ohms.

45

KOKUSAN-DENKI

BREAKERLESS

FLYWHEEL

MAGNETO

TYPE

GK

352 (Con't.)

5.3

Ignition Coil

Wipe

off

dust and

oil

with

care.

Check breaking

down

of

primary coil and secondary coil

by

using

an

ohm

tester.

Normal

primary

resistance

is

0.36 ohms and secondary

resistance

is

1100 ohms.

5.4 CDI

Unit

Clean

with

care

and check

the

following

points

with

tester:

(1) Resistance between

case

and lead wire

(white)

should

be

oo

.

(2) When connected

lead

wire

(white)

to

(+) terminal

of

tester and lead

wire

(brown)

to

(-)

terminal electricity

must

flow.

(3)

When

connected in

contrastwith

the above

electricity

must

not

flow.

(4)

lead

wire

(white)

by

(+)

{-)

of

tester. The resistance must

be

200M ohms

or

more.

(5) When sensitivity

of

the tester

is

raised

to

the

utmost

degree connect lead

wire

(black)

to

(+) and

lead

wire

(orange)

to

(-).

In

this

case

dial

of

the tester must swing

once and must return

to

its place.

NOTE:

The tester

to

be

used

for

the

above mentioned

must

be

for

3V.

46

NOTES

47

TROUBLE

SHOOTING -

TWIN

CYLINDER

IGNITION

PROBLEM

CHECK

NO SPARK

1.

Connection

1.

Check each coupler

2.

Stop switch

1.

Inferior

insulation

of

stop switch

2.

Short

circuit

of

lead wire

3.

Ignition coil

1.

Disconnection

of

primary winding

2.

Short

circuit

of

primary winding

3.

Disconnection

of

secondary winding

~

4.

Short

circuit

of

secondary

winding

00

(In 3 & 4 normal resistance

to

be

1100 ohms)

4.

Flywheel

1.

Breaking

of

exciter coil

(normally

250 ohms

magneto between plate and black lead)

2. Short

circuit

of

exciter coil

3.

Breaking

of

pulser coil (normally 65 ohms

between black lead and brown-white lead)

4. Short

circuit

of

pulser coil

5.

Short

circuit

of

breaking

of

lead wires

5.

COl

Unit

1.

Trouble

of

COl

unit

2.

Breaking

of

lead wire

j

)

PROBLEM

CHECK

WEAK

SPARK

1.

Connection

1.

Clean

dirt

on

each

coupler

2.

Stop switch

1.

Inferior

withstand voltage

or

insulation

of

stop switch

3.

Ignition

coil

1.

Dirt

on plug

cap

2.

Layer short

of

secondary winding

3.

Breaking

of

secondary winding

4.

Flywheel

1.

Breaking

of

exciter coil

~

magneto

2.

Layer short

of

exciter coil

~

3.

Layer short

of

pulser coil

5.

CDI

Unit

1.

Deterioration

of

CDI

unit

SPARKS CAN

BE

1.

Flywheel

1.

Breakage

of

key slot

of

crankshaft

OBTAINED

BUT

magneto

2.

Adverse magnetizing

of

flywheel magnets

IGNITION

TIMING

3.

Wrong connection

of

pulser coil

IS

OUT

OF

ORDER

2.

CDI

Unit

1.

Deterioration

of

CDI

unit

3.

Stop switch

1.

Inferior

withstand voltage

4.

Lead wire

1.

Cover

of

lead wire

is

torn

gJ

CIRCUIT

CHECKING OF COl

UNIT

BY

TESTER (OHM METER)

CONNECTION

BY

TO

CONNECT+

TERMINAL

OF THE TESTER

COLOR OF

LEAD

WIRES

BLACK

WHITE

BLACK-WHITE

BROWN ORANGE

I

-1

m

:c

s:

2-t

)>0

1'""(')

oo

"112

-t2

::tm mn

-1-t

m

en

-1

m

:c

STOP

LEAD

GROUND

LEAD

EXCITER

COIL

PULSER COIL

IGNITION

COIL

BLACK

~

OFF

TO

INDICATE

OFF

CON

ABOUT

20HMS

WHITE

ON

~

TO

INDICATE

ON

CON

ABOUT

20HMS

BLACK-WHITE

------------

BLACK-RED ON OFF

OFF

CON

BROWN OFF OFF

OFF

------

OFF

ORANGE CON OFF

OFF OFF

-------

NOTE:

"CON"

represents a characteristic

of

condenser - the needle

of

the tester swings once and returns straight. The swing

of

the

needle shifts

based

on the sensitiveness

of

a tester in

use;

when

the condenser

is

charged, the needle

will

not

swing

until

it

is

discharged.

THREE CYLINDER IGNITION

~

CRANKSHAFT

C.

D.

IGNITION

51

THREE

CYLINDER

IGNITION

KOKUSAN-DENKI

COMPANY,

LTD.

MODEL

NO.

AR3330

CAPACITOR DISCHARGE SYSTEM

1.

Specification

1.1

Type

Nos.

Generator: CDI

Unit:

Ignition Coils:

AR3330

(Production

Type

No.) CU1104 (Production Type No.) IG3501 (Production

Type

No.)

1.2

Characteristic and specification

Rotation

and

numbers

of

spark:

Clockwise, 3 sparks per

revolution

by

each

ignition coil.

Speed:

Spark

Output:

Lighting

Output:

Moment

of

inertia:

2.

Construction

2.1

Introduction

500-

1,000

RPM

(Max. 12,000

RPM)

7 mm or more at 500

RPM

16 mm and

less

at 7,000

RPM

12V, 75W (AC) at 4,500

RPM

13V

or

more at 4,500

RPM

16V

and

less

at 8,000

RPM

(To divide the

output

equally

to

two

lighting

leads,

35W

each)

6

kg-cm

2

approx.

In this CDI system

an

inner

rotor

magneto

is

used

for

its power source

for

generating electric current

to

charge

the primary condenser unti

I hundreds

of

voltage

is

stored.

The energy stored in the condenser

is

discharged

abruptly

to

primary windings

of

3 ignition coils, connected in

52

THREE CYLINDER IGNITION (Con't.)

series

to

generate high voltage in secondary coils at the

timed

relation

to

ignite

for

each

cylinder

of

engine.

Per

revolution

of

the

rotor,

3 sparks

can

be

obtained

for

each

cylinder,

but

only

one spark

is

used

for

actual

ignition and the other

two

wasted. Such

an

ignition

system

as

ours

is

called

"Capacitor

Discharge Ignition

System"

(in abbreviation CDI system).

Accordingly

this

CDI eliminates contact breakers and condensers in con-

ventional ways, in place

of

which

this

control

unit

named

"CDI

Unit"

embodying thristors, diodes, condensers, and

etc. therein.

2.2 Construction

of

Stator

The stator

has

six magnetic poles projecting in the inside

center which

are

of

laminated steel plates

with

plastic

powder coating.

Out

of

six,

four

pole cores are

directly

wound

coils and

two

leads

are

led

out

to

light

two

bulbs-

12V,

37.5W each. In this

case,

when one

bulb

is

gone, the

other

can

light normally.

The lighting

output

obtained also

can

be

used

for

one

bulb

only

of

75W

by

putting

those

two

leads together.

Next,

onto

the rest

of

the pole cores, the

same

number

of

exciting coils

which

work

as

the electrical power source

for

ignition are

put

and

fixed

by

fitting

plates.

Additionally,

this stator

is

also designed

to

mount

a coil

for

preventing inverse revolution

of

engine and

an

in-

dicator

for

the purpose

of

adjusting

ignition

timing

of

the

engine.

2.3 Construction

of

Rotor

The

rotor

has

such

an

outer

appearance

as

shown; a

boss

is

rivet-fixed

to

aluminum

diecast side plates,

on

the one

53

THREE CYLINDER IGNITION (Con't.)

side

of

which

three screwed holes

are

provided

to

mount

a cover

of

recoil stater. A six pole

emmit

shaped cast

magnet

with

pole pieces

of

laminated steel on its surfaces

is

fixed securely

by

rivetting between

both

of

the alu-

minum

side

plates.

2.4 Construction

of

CDI

Unit

The outer appearance

of

the CDI

unit

is

shown in the

drawing; a steel

case

has

two

flanges

for

mounting

by

each

two

holes

with

grommets. Inside

is

a plate

with

printed

circuit

providing CDI

circuit

and

an

inverse revolution

preventing

circuit

on it. The

former

circuit

comprises

of

a charge storing condenser and semi-conductor parts such

as

voltage rectifying diodes and

thyristors

etc. The latter

works

not

to

supply sparks

by

dissolving signal voltages

when the engine operates in the inverse direction. The

parts are molded together

with

polyester resin in the steel

case

for

providing para-shock construction.

Furthermore,

as

this CDI

unit

is

intended

for

three

cylinder engines,

even

if

one plug

of

the three

is

off,

this

can

run the engine in normal condition. However,

to

keep

the engine running under this circumstance

it

will

exert

vicious effect

to

the endurance

of

the ignition coi

Is

be-

cause

the

highest voltage

of

coils

will

be

produced between

the

coil terminals. Therefore, in order

to

prevent this, the

CDI

unit

protects the coils

by

all

of

the three coils

stopping instantaneously the supply

of

sparks.

When

the

generated voltage

from

such coils

can

not

be

discharged

anywhere in the consequence

that

one plug cap

is

off

at

the engine

speed

of

more than 3,000

RPM.

And

then,

when spark discharge

is

stopped and engine

speed

is

down,

the

thyristors

will

work

again

to

operate normally. In the

54

THREE

CYLINDER

IGNITION

(Con't.)

case

that

the engine runs

with

two

cylinders

out

of

three

due

to

troubles

of

engine itself, either the high tension

lead

of

the idle cylinder

will

short

circuit

or

with

the rest

two

cylinders engine

will

operate normally

if

all the plug

caps

are

kept fixed.

2.5 Ignition Coil The ignition coils

have

such

an

outer appearance

as

shown

in the drawing;

the

coil

has

closed iron core; wound coils

are

impregnated

by

epoxy resin and molded

tightly

by

thermo plasticity resin. These three coils

are

connected

by

their

primary coils through couplers in

series.

3.

Mounting and Dismounting

of

Generator

3.1

Mounting

(1) To

mount

the stator on

an

engine,

confirm

that

any

dust

and/or

chips

are

not

left

on the surfaces

to

be

set

together, and give

care

that

the coils

are

not

damaged.

Next,

mount

the stator on the engine and

fix

it

firmly

by

three

screws.

When inserting screws, avoid

to

force

leads

and/or

coils

shift

or

slide aside by using a driver

and etc.

(2) In mounting the

rotor,

remove anti-rust

oil

coated

on its surfaces and clean

the

shaft

with a dry

cloth.

on the

rotor

to

the engine shaft and screw

it

firmly

with

torque

of

60ft.

lbs.

(3) Mounting

of

COl

unit

and ignition coil

COl

unit

and ignition coil should be mounted

at

the well

ventilated places

with

environmental temperature below

60°C.

55

THREE CYLINDER IGNITION (Con't.)

(4) Connecting

of

Lead

Wires

Couplers

are

provided

for

connecting

each

lead wire,

so

connect them

firmly,

confirming

colors

of

each lead.

If

any

leads

are

left unconnected

or

off

in operation,

it

may

damage the

CDI

unit.

(5) Confirmation

of

ignition

timing

Si

nee

this

ignition

system

is

of

breakerless system, the

ignition

timing

will

hardly vary.

But

to

confirm

it,

use

a

stroboscope. When the mark

of

rotor

concides

with

that

of

indicator at the engine

speed

of

7,000

RPM

and under

the day

time

load

condition,

it

shows ignition

timing

is

normal

or

3.75 mm BTDC

or

26°

BTDC.

Use

a strobe

light

with

verified

reliability

for

it

is

occasional

that a low

intelligence strobe light shows the

timing

retarded,

as

it

has

retarded radiation itself.

3.2 Dismounting (1)

To

dismount

this

ignition

system, pull

out

the

rotor

first. Draw

out

hexagon nuts and then pull

out

the

rotor

by

a pull-out

tool

using three screw holes

for

fitting

recoi I

starter on the surface

of

the

rotor's

side plate.

Use

rotor

removal

tool

No. 2870159.

(2)

After

pulling

out

the

rotor,

loosen the screws

with

which stator

is

mounted

to

engine and also pull

out

the

stator

by

hand.

Be

sure

not

to

force

it

out

with

a driver

and/or

a hammer.

4.

Maintenance and Repair

In

ordinary

operation

of

the CDI system no repair

or

maintenance

work

is

required. However, dust, oil

and/or

muddy

water

is

undesirable

so

clean

them

if

covered.

to

see

if

there

is

any loosening

of

screws and the

connection

of

each

lead and coupler.

56

THREE CYLINDER IGNITION (Con't.)

4.1

Checking at the time

of

out

of

order

If

engine

does

not start

or

does

not run in good condition

and

if

checking

is

required

to

confirm whether

or

not

each

part

is

normal check the following:

(

1)

Lighting Coi I

Check

continuity

of

coils

to

the stator (ground potential)

and

the

lead

wire (yellow)

by

a circuit tester.

If

resistance

is

read

about 0.75 ohms

it

shows

coils

are

normal.

(2)

Exciter Coil I

If

the tester shows

that

the exciter coil

has

resistance

about

470 OHMS between the stator

and

the

lead

wire

(red)

it

is

normal.

(3) Exciter Coil II (Pulser Coil)

If

the tester

shows

resistance 20-22 ohms between

lead

wire

(green)

and

the

lead

wire (blue)

and

if

it

is

co

be-

tween the stator and the

lead

wire (either

green

or blue)

it

is

norma

I.

4.2 Ignition Coil (

1)

Using the tester, check

if

there

is

breakdown

of

a

primary

coil

and

secondary coil.

It

is

normal

if

the pri-

mary resistance

is

0.

7 Ohms

and

the secondary

is

12K

ohms.

4.3

CDI

unit

In general, the checking

of

CDI units

is

not

easy

and

it

is

desirable

to

use a unit

tester. But

if it

cannot be available

check

it

as

per the following

as

a preliminary method:

(

1)

If

resistance shown between the

unit

case

and

each

lead

wire

is

co.

(2)

If

a pointer

of

tester

moves

when connected between

the

lead

wire (black)

and

the plus terminal

of

tester and

57

THREE CYLINDER IGNITION (Con't.)

between the

lead

wire (white) and minus terminal

of

the

tester.

(3)

If

resistance

is

co

when connected inversely

to

the

above, the

lead

wire (black)

to

the minus

of

the tester and

the

lead

wire (white)

to

the plus

side.

(

4)

If

resistance

is

1-1OM

ohm when connected the

lead

wire (black

with

white stripes)

to

the plus,

and

the

lead

wire (red) and (white)

to

the minus.

(5)

If

resistance

is

10M ohm

or

more when connected

lead

wire (black

with

white stripes)

to

the plus,

and

the

lead

wire (black)

to

the minus.

(6)

If

a pointer

of

tester swings once

and

then

resets

when connected the

lead

wire (black

with

white stripe)

to

the plus,

and

the

lead

wire (orange)

to

the minus.

(7)

If

current flows when connected the

lead

wire (green)

to

the plus, and the

lead

wire (blue)

to

the minus.

(8)

If

resistance

is

oo

when inversely connected

to

the

above: the

lead

wire (green)

to

the minus, and the

lead

wire (blue)

to

the plus.

When

it

is

confirmed

that

the

unit

satisfies all

of

the above

checking items,

it

shows

that

the

unit

is

in normal con-

dition.

Next, clean dust

of

couplers and check its con-

dition. (In the above checking instructions, the plus

side

of

the tester

means

the anode poles

of

dry

cells included

therein.

58

THREE CYLINDER IGNITION (Con't.)

5.

Precautions in Operation

5.1

At

engine starting

Before starting engine, check connections

of

each

coupler

and loosening

of

each

screw and also

lead

wires

if

not

short circuit

to

the generator body.

5.2

When

couplers

are

off

or

lead

wires short circuit in

operation, the

following

troubles

are

likely

to

occur:

(

1)

Off

of

the couplers between the generator and the

CDI

unit

- - -

If

all

of

the couplers

are

off

instanta-

neously, there would

be

no trouble. However, the coupler

of

pulser

lead

be

off

first and then exciter

lead

gets

off,

the main

thyristor

would

be

damaged due

to

overvoltage.

(2)

Off

of

coupler between the CDI

unit

and ignition

coils - - - damage

of

the main

thyristor

due

to

overvoltage. (3)

Short

circuit

of

ignition

leads

and

lead

wire (orange)

---damage

of

main

thyristor

due

to

overvoltage.

(4)

Short circuit

of

lead

wire (white) - - - deteriora-

tion

of

main

thyristor

due

to

overvoltage.

(5)

Short

circuit

of

lead

wire (red) - - - no damage, however, no spark. (6)

Off

of

plug

caps

from

plugs in operation - - - no

damage, however, no spark.

5.3

To

stop

an

engine operation

To

stop

an

engine operation, stop

it

by

the stop

lead.

To

pull

out

couplers and/or plug

caps

in operation

of

engine

will

cause

such

troubles above mentioned.

59

THREE CYLINDER IGNITION (Con't.)

6.

Other Precautions

6.1

Measuring

of

Characteristics

of

the Ignition System

When

measuring characteristics

of

the ignition system

by

using a motor, there would

not

be

any troubles

if

the

generator runs in

regular direction

and

each

connected

portion

is

normal. However,

to

measure the spark

output

in inverse revolution,

be

sure

not

to

raise

its

speed

over

500

RPM.

Since this

unit

has

applied a circuit which dis-

solves

only

ignition signals in inverse revolution

not

to

supply spark in such occasion,

it

may

cause

charging vol-

tage

of

primary condenser

too

high value

at

high

speed

operation.

When

spark lengths are measured

by

three

needle

gap,

set

the

gap

length 1 mm except

to

use

testing

coils.

NOTES

60

NOTES

61

~

TROUBLE SHOOTING OF THREE

CYLINDER

IGNITION

SYSTEMS

PROBLEM

NO

SPARK

1.

Connection

2.

Stop switch

3.

Ignition

coil

4.

Magneto

5.

CDI

unit

CHECK

1.

Check each cou pier

1.

Inferior

insulation

of

stop switch

2.

Short

circuit

of

lead

wire

1.

2.

3.

4.

1.

2.

3.

4.

5.

1.

Breaking

of

primary

winding I

0

_

7

_n_

Short

circuit

of

primary

windi~

Breaking

of

secondary winding J

• • • 0 11,850

_n_

Short

c1rcu1t

of

secondary wmdmg

Breaking

of

exciter coil I

440

n

Short

circuit

of

exciter

c~

Breaking

of

pulser coil I

Short

circuit

of

pulser

c~

24

_n_

Short

circuit

of

control

coil 28

_n_

Breaking

of

lead

wire

2.

Wrong

circuit

of

CDI

unit:

red, white, and orange

-

-----

)

PROBLEM CHECK

WEAK

SPARK 1. Connection

1.

Clean

o~

dirt

of

each coupler

2.

Stop switch

1.

Inferior

insulation

of

stop switch

3.

Ignition

coil

1.

Dirt

on plug cap

2.

Short

circuit

of

primary winding

3.

Layer short

of

secondary winding

4.

Breaking

of

secondary winding

4.

Magneto

1.

Breaking

or

layer short

of

exciter coil

2.

Layer short

of

pulser coil

3.

Wrong connection

of

reverse

rotation

0')

prevention coil

w

5.

CDI

unit

1.

Wrong

circuit

of

red,

white & black-white

SPARK CAN

BE

1. Magneto

1.

Breakage

of

key slot

of

crankshaft

OBTAINED

BUT

2.

Adverse magnetizing

of

rotor

SPARK

TIMING

IS

3.

Wrong connection

of

pulser coil

OUT

OF ORDER

2.

CDI

unit

1.

Wrong

circuit

of

CDI

unit:

white, green,

blue & black-

white

ENGINE RUNS IN

1.

Magneto

1.

Breaking

of

adverse rotation prevention

THE

ADVERSE

coil

DIRECTION

BUT

2.

Layer short

of

adverse rotation

DOES

NOT

STOP

prevention coil

2.

CDI

unit

1.

Wrong

circuit

of

CDI

unit:

blue &

green

CU1117 (CU1104 TYPE)

CIRCUIT CHECKING OF CDI

UNIT

BY TESTER

CONNECTION

BY

TO

CONNECT-

TERMINAL

OF

THE

TESTER

COLOR OF L,

EAD

WIRES

EXCITER PULSER

STOP

EARTHING

PRIMARY

REVERSE

ROTATION

COIL COIL

LEAD LEAD

LEAD

PREVENTION

COIL

~

RED

WHITE

BLACK-WHITE

BLACK

ORANGE

BLUE

GREEN

+

RED

-----

OFF

--!

2M

fl

OFF OFF

OFF

m

--------

::0

WHITE

OFF

200-500

_fl_

OFF

ON ON

s:

---~

------------

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MIKUNI

CARBURETORS AND FUEL

PUMPS

'

I

needle

I I

I

~

~~Pi

lot

jet

I

'

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! Main 1

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~~~~-~-~-

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Fuel

...... Mixture

66

FUEL

PUMP

1.

Gasket

2.

Diaphram

3.

Valve

Troubles in this pump show themselves in a reduction

of

dis-

charge

volume due

to

the reduction

of

both discharge and

intake pressure. Causes

of

trouble

1.

Loose attachment

of

the inlet valve and the out-

let valve,

or

the

damage

or

wear

of

the valve spring.

2.

Damage

of

the

di-

aphragm

or

the membrane.

3.

Leak

of

wave motion

pressure.

4.

Leak

of

fuel due

to

poor piping.

Corrections

1.

Replacement

of

the pump

assembly.

2.

Replacement

with

a new

one. (When

reassembled, the

gas-

ketandthegasket

cap

also should

be

replaced at the

same

time.

3.

Check all joints

of

passage

of

the

wave

motion

from

the

crank chamber

to

the

bottom

body.

4.

Check the fuel pipe and the

elbow on the

sides

of

intake and

discharge.

67

FUEL PUMP (Con't.)

Causes

of

trouble

5. Other

leaks.

6.

Presence

of

dust

and

impurities.

7.

Clog

of

the filter.

NOTES:

Corrections

5.

Make

an

air-tight test. The

pump

should hold

11

P.S.I.

of pressure. (a)

If

the

leak

is

due

to

the

joint

of

the

top

body

and

the

bottom

body, replace the di-

aphragm and the gasket

with

new ones. (b)

If

the

leak

is

due

to

the

joint

of

the

top

body

and

the

cap,

replace the membrane and

cap

gasket

with

new

ones.

6.

Check the inlet

valve

and

the

outlet

valve.

7.

Clean

at regular intervals.

68

CARBURETORS

The Mikuni carburetor has varying

operations

depending upon

varying driving conditions.

It

is

constructed

with

the

float

system,

the

pilot system,

the

main system, and

the

starter

system

(initial starting device).

FLOAT SYSTEM

The

float system

is

designed

to

maintain a

constant

height

of

gasoline during operation. When

the

fuel flowing from

the

fuel

pump

into

the

float

cham-

ber

through

the

needle valve reaches

the

constant

fuel level,

the

float rises. When

the

buoyancy

of

the

float and

the

fuel pres-

sure

of

the

fuel

pump

balance,

the

needle valve sticks fast

to

the

needle seat, preventing

further

delivery

of

gasoline, there-

by

holding

the

standard level

of

gasoline.

The standard level

of

gasoline

is

set

at

below

30

m/m.± 1 from

the

center

of

the

main bore.

STARTER SYSTEM

The starter system

is

designed

to

make

the

engine

start

quickly

in

cold weather. It

is

constructed

with

functional parts such as

a starter jet, a starter

emulsion

tube,

and a starter plunger, etc.

When

the

engine starts

with

the

throttle

valve closed and

the

starter plunger wide

open,

the

intake negative pressure

of

the

engine works

on

the

fuel nozzle. By

this

negative pressure,

the

fuel

is

measured

by

the

starter

jet, mixed

with

air

in

the

starter

emulsion

tube,

absorbed

into

the

plunger chamber, mixed

again

with

air from

the

starter

air inlet, made

the

most suitable

concentration

of

fuel-air mixture

for

initial starting, and deliver -

ed

to

the

engine

through

the

fuel nozzle.

In

this

starter system,

you

can be sure

of

initial starting

without

any

skill

of

operation, since

both

fuel and air

are

measured and

the

constant

fuel-air mixture ratio

is

always correct.

69

CARBURETORS (Can't.)

PI

LOT SYSTEM

The

pilot

system

is

designed

to

deliver gasoline during idling and

low-speed driving. Fuel

for

idling

is

measured by the

pilot

jet, mixed

with

the air,

regulated

with

the air screw, mixed

again

with

the air

from

the

by-pass,

and

delivered

to

the engine through the

pi

lot

outlet.

The concentration

of

fuel-air

mixture

for

idling

is

determined

by

the air screw.

When

the air screw

is

closed, the amount

of

air

is

reduced

and

the fuel-air mixture

is

enriched. When the air

screw

is

opened, the amount

of

air increases

and

the fuel-air

mixture

is

lean.

When

the

throttle

valve opens slightly during low

speed

driving,

gasoline injects through the by-pass in addition

to

the fuel-air

mixture

from

the

pilot

outlet

to

secure smooth operation

of

the engine.

When

the

throttle

valve opens wider, approximately

above

1/8

of

the diameter

of

the main bore, gasoline injects

through the

needle jet. The adjustment

of

the

time

and amount

of

injection

from

the needle

jet

is

chiefly performed

by

the

cutaway furnished on the side

of

the air cleaner

of

the

throttle

valve.

MAIN

SYSTEM

The main system

is

designed

for

delivering fuel between

low

speed

driving

and

high

speed

driving.

The

fuel during the low

speed

driving

is

delivered

from

the

pilot

system

and

the main system. During intermediate

speed

driving (the opening

of

the

throttle

valve

is

above 1/4), the

fuel

is

largely delivered

from

the main system. The fuel during

intermediate

speed

driving flows

into

the needle

jet

through

the main

jet

and

mixes

with

the air measured

by

the air-jet

to

make a fine spray

of

fuel-air

mixture

of

good quality.

70

CARBURETORS (Can't.)

The point

of

the

jet

needle

is

tapered

to

adjust the

flow

of

fuel-

air mixture in accordance

with

the opening

of

the

throttle

valve.

During high

speed

driving (the opening

of

the

throttle

valve

is

above 3/4), the fuel

is

measured

by

the main

jet

and

mixed

with

the air measured

by

the air

jet

to

make a fine spray

of

fuel-air mixture

of

good

quality

for

delivery

to

the engine. ADJUSTMENTS When

the engine

has

dual carburetors,

it

is

the prerequisite

for

full

engine performance

to

maintain the equal operation

of

each

carburetor. The following items should

be

followed

cautiously

and accurately.

ADJUSTMENT OF

THROTTLE

CABLE

With your

eye

or plug

gauge,

adjust the opening

of

each

throttle

valve

with

the

throttle

cable attached and

the

throttle

open. With

your

eye, you

can

adjust accurately

by

matching

the corner

of

the cutaway

of

the

throttle

valve

with

the

upper

surface

of

the main bore.

After

adjustment,

be

sure

to

fasten

the

cable adjuster lock nuts

as

well

as

the starter wire.

ADJUSTMENT

OF

IDLING

AND

SYNCHRONIZATION

(a)

Set the air

screw

of

each

carburetor at the standard

return number

and

then fasten the

throttle

stop screw

of

each

carburetor evenly, setting the number at about 1,000

RPM

which

is a little

higher than normal idling

speed.

(b)

Warm up the engine completely.

(c)

Find

out

and

set

the position where the number

of

RPMs

of

the engine becomes maximum

by

opening

or

closing the air

screws

one

by

one about 1/2

each

time. In this

case,

be

sure

to

use

a tachometer.

(d) Return

each

screw

of

the

throttle

valve evenly and

set

at

the

normal number

of

rotations

of

idling.

71

CARBURETORS (Con't.)

(e)

Find

out

and

set

the position once more where engine

rotation

becomes maximum

by

opening

or

closing the air

screws

one

by

one about

1/16

each

time.

(f)

If

the

number

of

rotations

has

changed

in

the adjustment

mentioned in paragraph (e),

set

once more at the normal

number

of

rotations

of

idling

by

means

of

each

throttle

stop

screw.

(g)

Remove the plug cap

of

each

cylinder and check whether

the down percentage in the number

of

rotations

of

the engine

is

constant

or

not

at

that

time.

If

not,

return the

throttle

stop

screw

on

the side where the

down

percentage

is

larger and adjust

so

as

to

make the

down

percentage constant.

(h) In the last step, operate

for

5-10 minutes

by

idling.

If

the rotations

of

the engine

are

normal during

that

time, the

adjustment

is

complete.

If

abnormal, remove the ignition plug

and check the

condition

of

combustion.

If

the combustion

seems

to

be

somewhat over, return the air screw, and

if

some-

what under, fasten the air screw.

ADJUSTMENT IN ACCORDANCE WITH THE ALTITUDE AND THE TEMPERATURE

The density

of

the

air varies according

to

the

altitude

and the

temperature.

It

is

necessary

that

the delivery

of

the fuel in the

carburetor should

be

changed according

to

the change

of

the

density

of

the air.

INITIAL

STARTING

For initial starting in cold weather, start the engine

with

the

choke

full

open. On

this

occasion,

it

is

necessary

to

be

careful

not

to

open the

throttle

valve.

If

you open the

throttle

valve,

the

negative pressure

working

for

the injection

of

the

fuel

for

72

CARBURETORS (Can't.)

the starter drops and the intake

of

the fuel becomes weak.

When

the engine

has

started, warm up the engine

with

the choke

engaged.

After

warm up, return choke

to

normal position.

When

starting

an

engine

that

is

already warm, activate

throttle

slightly (about 1 /3).

OVERHAUL

SERVICE

As

you may

have

understood

by

the preceding explanations,

a carburetor

has

little

mechanical functions,

and

troubles

are

mostly due

to

the wear

of

parts

and

the clog

by

dirt

and dust.

In overhaul service,

use

gasoline

for

washing

out

and

blow

dry

with

an

air compressor. Observe the

following

instructions.

STARTER SYSTEM

(a)

The starter

jet

is

driven into the float chamber body. Jets

should never

be

cleaned

by

drills

or

wire.

(b)

Be

careful in handling the starter plunger, since scratches

on the circumference

cause

malfunctioning and scratches on

the

base

prevent a

tight

seal

which

may

cause

a fuel leak while

driving.

(c)

Since a damaged

or

worn rubber cap

of

the starter allows

the invasion

of

water

from

outside, replace

it

with

a new one.

PILOT SYSTEM

(a)

Be

sure

to

use

proper tools

for

overhauling the

pilot

jet,

and

be

careful

not

to

make scratches.

Wash

out

in gasoline and

blow

dry

with

an

air compressor.

(b)

If

the taper

of

the air screw

is

disfigured

or

worn, replace

it

with

a new one.

(c)

When

the

pilot

jet

and

the air screw

are

disassembled,

carefully clean the

passages

on the side

of

the body (the

pilot

outlet

and the by-pass, etc.).

73

CARBURETORS (Can't.)

MAIN

SYSTEM

(a)

Be

sure

to

use

proper tools

for

disassembling the main jet

and the needle jet, and

be

careful

not

to

make scratches when

reassembling. (Excessive tightening

is a cause

of

disfigure

or

damage.)

FLOAT

SYSTEM

(a)

Be

careful

not

to

bend the

float

guide pin in handling.

If

bent, the pin

causes

malfunctioning

of

the float.

(b) The needle valve

can

be

disassembled

into

the

valve

seat

and

the

float

valve. When

it

is

replaced

because

of

wear

or

scratches,

use

the complete needle valve assembly.

(c)

Every

time

overhaul

is

performed, replace the

float

cham-

ber packing

with

a new one.

DISORDER

AND

ADJUSTMENT

A carburetor

is a vessel

with a lot

of

precision jets

and

a con-

stant

fuel level.

It

is

so

constructed

that

when the negative

pressure

of

intake

of

the engine functions, proper concentration

of

fuel-air

mixture

is

obtained

for

the operation

of

the engine.

Accordingly, except

for

the mechanical disorders, most carbure-

tor

problems

are

caused

by

an

abnormal concentration

of

the

fuel-air

mixture

due

to

accumulated

dirt

and dust

and

wear

of

parts.

Disorders

of

the engine due

to

an

abnormal fuel-air

mixture

are

as

follows:

When

the fuel-air

mixture

is

too

rich:

(

1)

The rotations sound overwrapped

and

intermittent.

(2) When the choke

is

opened, the condition worsens.

(3)

When

the engine

is

warmed up, the condition worsens.

(4) The ignition

plug becomes dark

and

dusty.

(5) Exhaust

gas

is

rich.

74

CARBURETORS

(Can't.)

When the

fuel-air

mixture

is

too

lean:

(

1)

The engine

is

over-heated.

(2)

When

the choke

is

opened, the

condition

becomes better.

(3)

Acceleration

is

poor.

(4)

The

ignition

plug

is

burnt.

(5) Rotations

are

irregular.

(

6)

Exhaust

gas

is

lean.

Our

carburetor

is

so

constructed

that

the parts

to

adjust vary

according

to

the degree

of

throttle

opening.

After

having

checked whether the

cause

of

disorder

is

due

to

an

over-rich

mixture

or

to

over-lean

mixture,

confirm

what parts must

be

adjusted

for

a specific

throttle

opening.

The

relation between the degree

of

the opening

of

the

throttle

valve and the functional systems and the parts

to

adjust

is

as

follows:

Throttle Valve

Degree

of

Opening

0 - 1/8 1/8 - 1/4 1/4 - 3/4

3/4 -

Full Open

Functional System Pilot System Pilot

System

Main System

Parts

to

Adjust

Air

Screw

Throttle Valve

Jet Needle

Main Jet

Air

Screw

When the

condition

of

disorder and the degree

of

opening

have

been

confirmed,

first

check and clean the

functional

systems

and then adjust the parts in question.

DEGREE

OF

OPENING:

0-

1/8,

air screw

When the opening

is

closed, the

amount

of

air reduces and the

fuel-air

mixture

becomes rich.

When

the opening

is

opened,

the

amount

of

air increases and

the

fuel-air

mixture

becomes lean.

75

CARBURETORS (Con't.)

DEGREE

OF OPENING:

1/8-

1/4,

air

screw,

throttle

valve

When

the cutaway

of

the

throttle

valve

is

made

larger, the

neg-

ative

pressure

which works on the needle

jet

reduces,

and

the

fuel-air mixture becomes

lean.

When

the cutaway

of

the

throttle

valve

is

made

smaller, the

negative pressure which works on the

needle

jet

becomes rich.

The cutaways

are

prepared at intervals

of

0.5

m/m

alternately.

(Note) The adjustment

of

the opening

can

be

made

either

by

the

throttle

valve

or

the air screw. However,

so

far

as

the idling

is

not

in disorder,

make

adjustment

by

the air

screw.

DEGREE OF OPENING:

1/4-

3/4, jet

needle

The

jet

needle

has 5 levels

of

groove.

When

the grip

goes

upward

(2nd

& 1st

levels)

the

space

between the

jet

needle

and

the

needle

jet

becomes smaller

and

the fuel-air mixture becomes

lean.

When

the grip

goes

downward, the

space

between the

jet

needle

and

the needle

jet

becomes larger

and

the fuel-air mix-

ture becomes rich.

DEGREE OF OPENING:

3/4-

full

open,

main

jet

When

the larger number

is

used,

the fuel-air mixture becomes

rich.

When

the smaller number

is

used,

the fuel-air mixture

becomes

lean.

CHECK AND ADJUSTMENT OF THE FLOAT SYSTEM

The overflow during driving or operation

of

the engine could

be

caused

by

a loose attachment due

to

worn needle

valves,

the

clog

of

dirt

and dust,

and

the malfunctioning

of

the float, etc.

Needle

Valve-

Worn.

Spring

is

damaged or worn - replace

with

a new

one.

Spring

seat

is

worn

or

scratched.

76

CARBURETORS (Con't.)

Clogged

with

dirt

and

dust-

cleaning.

Float-

Malfunctioning due

to

bent guide

pin-

adjustment.

Float

Arm-

Malfunctioning due

to

clog-

adjustment.

Over-height

of

the fuel level.

Remove the float chamber and

measure

the height

from

the

level

of

the float chamber packing

to

the float arm when the

mixing body

is

placed upside down

and

the float chamber

packing

is

removed. Make adjustment

so

that

the height

is

within

22.5-23.0

m/m.

NOTES:

77

KEIHIN CA'RBURETORS

SCHEMATIC

VIEW

Your

1973

TX

Starfire 439 and 650 machines

will

be

equipped

with

Ke

ihin carburetors. The 439

with

model RD38, and the

650 wit h model R D50.

Each of t

hese

carburetors

has

been

calibrated and adjusted

for

its given engine

size.

The

following

service and trouble shooting

information

will

be

a great benefit

to

you.

MAIN

NOZZL

E

/

HI

GH

SPEED

MIX

SCREW

VALVE SEAT

I

NLET

CONT ROL VALVE

I

NLE

T CON TROL LE V

ER

I

NLET TENSION

SPRING

OUTLET

CHECK VALVE

LOCK

SCR

EW

PRI

MARY

VENTURI

_)

78

IDLE DISCHAR

GE PORT

P

UL

SE CHAMBER

~

FUEL PUMP DIAPH RAGM

REGU LAT

OR

CHAMB

ER

MA

IN DIAPHRAGM

DI

APHR AGM SPRI NG

ADJUSTMENT SCREW

SERVICE INSTRUCTIONS

As

improper adjusting

or

servicing could result in poor engine

performance,

it

is

very

important

that

the correct procedure

be

followed

when cleaning, checking

or

replacing worn

or

damaged parts.

Before opening the carburetor consult the trouble shooting chart. Always

use

genui

ne

Keihin replacement parts.

OVERHAUL

1.

DISMANTLING

AND

CHECKING OF THE PUMP SEC-

TION:

a)

Loosen the six screws and remove the pump section

from

the main body.

b)

Check the

pump

diaphragm. As the pump diaphragm

is

made

of

thin

stainless steel,

it

should

be

handled

with

care. Replace,

if

damaged

or

deformed.

c)

Check the gasket between the pump and mixing

body

and

also

the

gasket inside

the

pump body. Replace

if

necessary.

d) Check the

"0"

ring in the mixing

body

and pump

body

and replace,

if

necessary.

e)

Check and replace the check valve

if

damaged

or

worn.

Caution should

be

used

not

to

pull

or

roll

the

check valve

as

this

part

is

made

of

extra

thin

synthetic rubber material.

f)

Check

if

the surface

of

the

brass

valve

seats

is

smooth.

Replace

pump

body

if

necessary

as

the valve

seats

are

bonded

into

the

pump

body.

g)

Check the regulator diaphragm being careful

not

to

pull

~

or

roll

it. Replace,

if

broken.

2.

CHECKING

OF

THE

REGULATOR

CHAMBER:

a)

Confirm

that

the

top

of

the

inlet

control

lever

is

adjusted

properly

so

as

to

be

flush

with

the

floor

of

the

regulator

chamber.

79

SERVICE INSTRUCTIONS (Con't.)

b)

If

the inlet

valve

does

not

close

or

function properly

(sticking

or

not

seating well), dismantle

by

removing the

small screw taking

care

not

to

lose

the inlet tension spring

when removing the

lever.

c)

Check

if

the

tip

of

the valve and the inner surface

of

the

valve

seat

are

smooth.

d)

Replacement

of

valve

and

valve

seat:

1.

Only

if

the

tip

of

the valve

is

damaged replace this part

only.

2.

If

both valve

and

seat

are

damaged, replace the old

valve

seat

using a

flat

punch.

3.

According

to

the condition

of

the regulator chamber,

install either a standard

or

one

of

the

two

sizes

of

oversize

seats

available

but

always

use a flat

punch

so

as

not

to

damage

the inside part

of

the new

seat.

e)

Check the inlet control lever and pin and replace

if

necessary.

3.

DIAPHRAGM

SPRING:

Check,

and

replace,

if

deformed.

4.

MIXING

BODY

a)

Remove

both

idle and high

speed

mixture

screws.

b)

Check the tapered ends

of

both

screws

and

the orifices

of

the body.

c)

Replace

if

the ends

of

the screws

are

damaged

or

the

orifices

are

deformed.

d)

Remove the cover

of

the idle by-pass port

by

removing

the

two

small

screws.

Then check

for

blocking

of

the

by-

pass

port.

Air

pressure should

be

used

to

blow

out

any

dirt.

Never

use

a wire

or

dri

II

so

as

not

to

damage the orifice.

5.

RE-ASSEMBLING:

a)

Re-assembly while being careful

that

all the fuel

passages

80

SERVICE INSTRUCTIONS (Con't.)

through the gaskets, pump diaphragm, pump body and mixing chamber coincide.

b)

Make

sure

that

the

check valve

is

correctly positioned in

the pump

body

(in line

with

the valve

seats).

c)

Make

sure

that

the inlet tension and diaphragm springs

are

correctly positioned.

d)

Replace the six screws which

fix

the pump section

to

the

main body.

e)

Secure counterpoint screw one

by

one

to

prevent de-

forming the pump cover.

6.

ADJUSTMENTS:

Four separate adjustments

are

required

following

the

above overhaul procedure.

a)

FUEL

LEVEL.

b)

IDLE

MIXTURE

SCREW.

c)

IDLE

SPEED SCREW.

d) HIGH SPEED

MIXTURE

SCREW.

a)

FUEL

LEVEL:

Install fuel level checking parts and start the engine.

Loosen lock screw and

turn

the adjustment screw.

(See

figure) Fuel level in

vinyl

tube must come in line

with

under-

neath fringe

of

the

mixing body. Fuel level in vinyl tube must

come in line

with

underneath fringe

of

the

pump

body

(and

not

the pump

body

ass'y.)

Secure the adjustment screw

by

the lock screw. Do

not

over-

tighten

so

as

not

to

damage the adjustment screw.

b)

IDLE

MIXTURE

SCREW:

Adjust the idle

mixture

screw

until

smooth engine running

is obtained. Clockwise

turning

results leaner mixture, counter-clockwise

turning results richer mixture.

81

SERVICE INSTRUCTIONS (Con't.)

Normal adjustment

is

approximately

1-1/4

turn

counter-clock

wise

from a full

closed position.

c)

IDLE

SPEED

SCREW:

Adjust

idle

speed

as

per engine manufacturer specifications.

d)

HIGH

SPEED

MIXTURE

SCREW:

Adjust

high

speed

mixture

screw

so

as

to

reach maximum revolution. This adjustment should

be

made

with

throttle

valve

fully

opened and normal load

for

the engine.

Normal adjustment

is

approximately 1

turn

counter-clockwise

from a fully

closed position.

NOTES

82

FLOAT

LEVEL

Idle

speed

screw

Fue

l leve l

Adjust

the

level

so

as

the

fuel

level in

vinyl pipe

comes

on

line with

the fringe

of

the

pump

body.

To

raise the

fuel

level,

turn

the screw

clockwise-

to

lower

the

fuel

level,

turn

the

screw

counter-clockwise.

83

Id le mix

screw

High

speed

mix

screw

Washer

--------

Screw

8

rcau-.

(A_ttac

_h

the

scr

ew

and

washer after

adJUSting

fuel

level).

A1r rel

ease

plug

screw

Fuel level ch

ecking

parts

Fuel level adju

stment

screw

L

ock

screw

(Lock the

screw

after

adjusting

fuel

leve

l)

TROUBLE SHOOTING

KEIHIN RD38 AND RD50

A. OVERFLOW: CAUSES

1-Dirty

inlet

valve.

2-lnlet

valve

does

not close; 3-lnlet

control lever

not

operating smoothly.

4-lncorrect

fuel level.

5-Worn

inlet valve

B.

POOR

STARTING:

CORRECTIONS

1-Remove

valve, clean and/or replace. 2-Check

valve

seat

and replace valve. 3-Replace lever

or

adjust accord-

ing

to

instructions.

4-Adjust

according

to

instructions. 5-Replace

inlet

valve.

CAUSES CORRECTIONS 1-Chok

ing

in the fuel line.

1-Ciean

fuel line

with

compress-

ed

air.

2-Fuel

pump

not

working.

2-Check

the component parts,

the impulse tube and the check

valve.

3-lnsufficient

fuel supply.

3-Check

fuel supply and

for

blocked fuel line.

4-

Low fuel level.

C.

POOR

IDLING:

CAUSES

1-lncorrect

adjustment.

2-lncorrect

level

of

inlet

control lever.

3-1

nsufficient pumping.

4-Adjust

fuel

level.

CORRECTIONS

1-Adjust

idle mixture and

speed

screws,

and check fuel

level.

2-Adjust

inlet control lever flush

with

the

floor

of

the regulator chamber. 3-Check

pump and component

parts, impulse tube and orifice.

84

TROUBLE SHOOTING (Con't

.)

D.

POOR HIGH SPEED PERFORMANCE: CAUSES 1-Poor

adjustment.

2-lnsufficient

fuel supply.

3-Choking

in the fuel line.

4-Biocked

fuel

filter.

5-lncorrect

fuel level.

IMPORTANT

CORRECTIONS 1-Adjust

high

speed

mixture

screws.

2-Release air

by

loosening screw

plug

with

engine idling.

3-Check

and clean fuel line.

4-Replace

fuel filter.

5-Adjust

fuel level.

a)

To

obtain constant performance, the carburetor should

be

cleaned and checked at reasonable intervals.

b)

Dust

or

dirty

parts

are

the usual

causes

of

carburetor

troubles.

c)

Never

use

solvents

which

can

damage the synthetic rubber

parts

of

the

carburetor.

d)

It

is

recommended

to

use

gasoline

for

cleaning.

e)

The

use

of

a high

quality

filter

is

necessary

to

insure

proper operation.

NOTES

85

WARRANTY

Although the

TX

Starfire

is

subject

to

a stringent Polaris

quality

control program

to

insure maximum dependability,

Polaris, A Textron Company,

will

not

warranty any snow-

mobile

used

for

racing

or

competitive

use,

including the 1973

TX

Starfire high performance snowmobile.

86

SAFETY

Your

1973

TX

Starfire Racer

is

designed and

built

for

competi-

tion

use.

It

does

not

conform

to

ISlA

and many state laws and

standards governing noi

se

and

lighting. Do

not

operate this

machine

for

any other purpose than in sanctioned competi-

tion

events.

When operating

this

machine familiarize yourself

with

it

before

any

full

throttle

runs. Get the feel

of

the

braking system and

always connect the cord

for

the

tether

stop switch

to

you

r-

se

lf before starting.

Always

wear protectiv

e clothing when operating

your

TX

Starf ire.

We

recommend

that

you wear the

following:

1.

Full coverage approved helmet

2.

Goggles

3.

Ankle

high leather topped boots

4.

Knee and shin pads

5.

Shoulder and

rib

pads

6. Hearing

plugs (earplugs)

87

NOTES

88

1973

TX

Starfire

Owners

Registration

(Please

Print)

Name:

__________________________________

________

______

__

Street Address:

______________________

_

Telephone No.

__

_

City:

_______

_

State:

____

_

Zip

Code:

____

_

TX

Starfire Serial

Number:------------------

TX

Starflame Engine Number:

________________

__

Dealer's

Name:---------------------

-

City:

State:

____

_

Zip

Code:

____

_

Polaris

Distributor: ----------------------------------

/P~;~laris.

A

textron

I

company

ROSEAU,

MINNESOTA

part No.

9910206