Yamaha YP250 User Manual

EB000000

YP250

SERVICE MANUAL

1996 by Yamaha Motor Co., Ltd.

1st Edition, January 1996
All rights reserved. Any reprinting or
unauthorized use without the written

permission of Yamaha Motor Co., Ltd.

is expressly prohibited.

EB001000

NOTICE

This manual was produced by the Y amaha Motor Company primarily for use by Yamaha dealers and
their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual,
so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha
scooter has a basic understanding of the mechanical ideas and the procedures of scooter repair. Re­pairs attempted by anyone without this knowledge are likely to render the scooter unsafe and unfit for
use.

Y amaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and signifi­cant changes in specifications or procedures will be forwarded to all authorized Y amaha dealers and
will appear in future editions of this manual where applicable.

NOTE:

Designs and specifications are subject to change without notice.

IMPORTANT INFORMATION

Particularly important information is distinguished in this manual by the following notations.

The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED!

Failure to follow WARNING instructions could result in severe injury or death
the scooter operator, a bystander or a person inspecting or repairing the scoot­er.

CAUTION:

NOTE: A NOTE provides key information to make procedures easier or clearer.

A CAUTION indicates special precautions that must be taken to avoid damage
to the scooter.

to

YP002000

HOW TO USE THIS MANUAL

MANUAL ORGANIZATION

This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”)

1

1st title
2nd title

3rd title

EXPLODED DIAGRAMS

T o heps identify parts and clarify procedure steps, there are exploded diagrams at start of each remov­al and disassembly section.

1. An easy-to-see exploded diagram

2. Numbers 5 are given in the order of jobs in the exploded diagram. A number that is enclosed by a

3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks

4. A job instruction chart

5. For jobs requiring more information, the step-by-step format supplements

: This is the title of the chapter with its symbol on the upper right corner of each page.

2

: This title indicates the section of the chapter and only appears on the first page of each

section. It is located in the upper left corner of the page.

3

: This title indicates a sub-section that is followed by step-by-step procedures accompa-

nied by corresponding illustrations.

4

is provided for disassembly and assembly jobs.

circle indicates a disassembly step.

6

. The meanings of the symbol marks are given on the next page.

7

accompanies the exploded diagram, providing the order of jobs, names

of parts, notes in jobs, etc.

8

are given in addition

to the exploded diagram and the job instruction chart.

2

5

6

7

1

6

4

3

8

EB003000

1

2

ILLUSTRATED SYMBOLS

Illustrated symbols 1 to 9 are designed as
thumb tabs to indicate the chapter’s number
and content.

3

5

7

4

General information

1

Specifications

2

Periodic inspection and adjustment

3

Engine

4

Cooling system

6

5

Carburetion

6

Chassis

7

Electrical

8

Troubleshooting

9

8

9

11

13

15

18

21

10

12

14

16

19 20

22 23

17

Illustrated symbols 10 to 17 are used to identify
the specifications appearing in the text.

10

Possible to maintain with engine mounted

11

Filling fluid

12

Lubricant

13

Special tool

14

Tightening

15

Wear limit, clearance

16

Engine speed

17

Ω, V, A

Illustrated symbols 18 to 23 in the exploded dia­grams indicate the types of lubricants and lu­brication points.

18

Apply engine oil

19

Apply gear oil

20

Apply molybdenum disulfide oil

21

Apply wheel bearing grease

22

Apply lightweight lithium-soap base grease

23

Apply molybdenum disulfide grease

24 25

Illustrated symbols 24 to 25 in the exploded dia­grams indicate the where to apply locking agent

24

and when to install new parts 25.

24

Apply locking agent (LOCTITE)

25

Use new one

INDEX

GENERAL INFORMATION

SPECIFICATIONS

PERIODIC INSPECTION AND
ADJUSTMENT

ENGINE OVERHAUL

COOLING SYSTEM

GEN

INFO

SPEC

INSP

ADJ

ENG

COOL

1
2
3
4
5

CARBURETION

CHASSIS

ELECTRICAL

TROUBLESHOOTING

CARB

CHAS

ELEC

TRBL

SHTG

6
7
8
9

CHAPTER 1

GENERAL INFORMATION

SCOOTER IDENTIFICATION 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VEHICLE IDENTIFICATION NUMBER (for E) 1-1. . . . . . . . . . . . . . . . . . .

FRAME SERIAL NUMBER 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ENGINE SERIAL NUMBER 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MODEL LABEL 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FEA TURES 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

OIL INDICATOR LIGHT 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AUTO CHOKE SYSTEM 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IGNITION CIRCUIT CUT-OFF SYSTEM 1-3. . . . . . . . . . . . . . . . . . . . . . .

IMPORTANT INFORMATION 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PREPARATION FOR REMOVAL PROCEDURES 1-4. . . . . . . . . . . . . . .

REPLACEMENT PARTS 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GASKETS, OIL SEALS, AND O-RINGS 1-4. . . . . . . . . . . . . . . . . . . . . . . .

LOCK WASHERS/PLATES AND COTTER PINS 1-5. . . . . . . . . . . . . . . .

BEARINGS AND OIL SEALS 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CIRCLIPS 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHECKING OF CONNECTIONS 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HOW TO USE THE CONVERSION TABLE 1-7. . . . . . . . . . . . . . . . . . . . .

SPECIAL TOOLS 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOOTER IDENTIFICATION

YP100000

GENERAL INFORMATION

SCOOTER IDENTIFICATION

YP100010

VEHICLE IDENTIFICATION NUMBER (for E)

The vehicle identification number
into the right side of the frame.

NOTE:

The vehicle identification number is used to
identify your scooter and may be used to regis­ter your scooter with the licensing authority in
your country.

YP100020

FRAME SERIAL NUMBER (except for E)

The frame serial number
right side of the frame.

GEN

INFO

1

is stamped

1

is stamped into the

EB100030

ENGINE SERIAL NUMBER

1

The engine serial number

is stamped into the

crankcase.

NOTE:

Designs and specifications are subject to
change without notice.

MODEL LABEL

1

The model label

is affixed under the seat.
This information will be needed to order spare
parts.

1-1

GEN

FEATURES

FEATURES

OIL INDICATOR LIGHT
 Function

Pulses (travel distance signals) from the speedometer are counted and cause the oil indicator light to
come on at 1,000 km for the first time and thereafter every 3,000 km. In this way , this light indicates the
time for oil change.

 Circuit diagram

Main
switch

Oil indicator light

Fuse

Battery

Engine stop
switch

Reset button

Meter

Ignitor unit

Oil indicator light

C.P.U

INFO

Reset button

 Resetting procedure

Travel distance can be reset if the reset button is held down for 2 to 5 seconds with the main switch
“ON”.

1) If the “resetting” is done while the oil light is on, the oil indicator light goes off for resetting con­firmation.

2) If the “resetting” is done while the oil light is off, the oil indicator light comes on for 1.4 seconds
for resetting confirmation.

 Failure diagnosis

1) Checking oil indicator light for breakage
This oil indicator light is kept on for 1.4 seconds immediately after the main switch is turned on,
thereby checking the bulb for breakage.

2) In case of meter pulse failure
If travel distance signals are not detected during running, the oil indicator light flashes and gives a
warning of meter signal failure.

NOTE:

This circuit may be activated if the engine is accelerated without load with the mainestand put up.

 Battery tending to discharge.

If the starting motor is run with the battery tending to discharge, the oil indicator light may come on (for

1.4 seconds), but this is noting abnormal.
In this case recharge or replace battery.

This light comes on if battery charging becomes poor, thereby causing the engine to run
as low as about 200 rpm against 600 rpm or so,

1-2

GEN

FEATURES

AUTO-CHOKE SYSTEM

This system is the parallel connection of the ignitor unit circuit and the thermo switch as shown, detect­ing the engine temperature, and facilitates the restarting with the warm engine.

 Circuit diagram

Main switch

Igniter unit

INFO

Fuse

Battery

Thermo
switch

Auto-choke

Ignition

C.P.U

 Auto-choke operation

Engine condition

Start with the
cold engine

Crank with the
cold engine

Crank with the
warm engine

Restart with the

warm engine
Thermo switch OFF OFF ON ON
Ignitor unit circuit OFF ON ON OFF
Auto-choke Activates Activates Not activate Not activate

IGNITION CIRCUIT CUT-OFF SYSTEM

A sidestand circuit is added to the existing electric starting circuit, thereby controlling the starter motor
operation and the ignition system of the igniter unit.

 Circuit diagram

Main switch

Engine stop switch

Battery

 Operating mode

Sidestand switch

OFF

(Sidestand in use)

ON

(Sidestand folded in)

Fuse

Starter relay

Brake
switch

Starter
motor

Start
switch

Operation of brake

light

ON Not operated Misfire

OFF Not operated Misfire

ON Operated Ignited

OFF Not operated Ignited (ridden)

Relay

Brake light

Sidestand
switch

Operation of starter

motor

Ignitor unit

Operation of igniter

unit control

1-3

IMPORTANT INFORMATION

EB101000

IMPORTANT INFORMATION

PREPARATION FOR REMOVAL PROCE­DURES

1. Remove all dirt, mud, dust and foreign ma­terial before removal and disassembly.

2. Use proper tools and cleaning equipment.

3. Refer to the “SPECIAL TOOLS” section.

4. When disassembling the machine, always
keep mated parts together. This includes
gears, cylinders, pistons and other parts
that have been “mated” through normal
wear. Mated parts must always be reused
or replaced as an assembly.

5. During machine disassembly, clean all
parts and place them in trays in the order of
disassembly. This will speed up assembly
and allow for the correct installation of all
parts.

6. Keep all parts away from any source of fire.

GEN

INFO

EB101010

REPLACEMENT PARTS

1. Use only genuine Yamaha parts for all re­placements. Use oil and grease recom­mended by Y amaha for all lubrication jobs.
Other brands may be similar in function and
appearance, but inferior in quality.

EB101020

GASKETS, OIL SEALS AND O-RINGS

1. Replace all gaskets, seals and O-rings
when overhauling the engine. All gasket
surfaces, oil seal lips and O-rings must be
cleaned.

2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.

1-4

OR

IMPORTANT INFORMATION

EB101030

LOCK WASHERS/PLATES AND COTTER
PINS

1. Replace all lock washers/plates and cotter
pins after removal. Bend lock tabs along the
bolt or nut flats after the bolt or nut has been
tightened to specification.

EB101040

BEARINGS AND OIL SEALS

Install bearings and oil seals so that the
manufacturer’s marks or numbers are visible.
When installing oil seals, apply a light coating of
lightweight lithium base grease to the seal lips.
Oil bearings liberally when installing, if appropri­ate.

Oil seal

1

GEN

INFO

CAUTION:

Do not use compressed air to spin the bearings
dry. This will damage the bearing surfaces.

Bearing

1

EB101050

CIRCLIPS

1. Check all circlips carefully before reas­sembly. Always replace piston pin clips af­ter one use. Replace distorted circlips.

1

When installing a circlip
the sharp-edged corner
posite the thrust 3 it receives. See section­al view.

Shaft

4

, make sure that

2

is positioned op-

1-5

IMPORTANT INFORMATION

EB801000

CHECKING OF CONNECTIONS

Dealing with stains, rust, moisture, etc. on the
connector.

1. Disconnect:
S Connector

2. Dry each terminal with an air blower.

3. Connect and disconnect the connector two
or three.

4. Pull the lead to check that it will not come
off.

5. If the terminal comes off, bend up the pin
and reinsert the terminal into the connector.

GEN

INFO

1

6. Connect:
S Connector

NOTE:

The two connectors “click” together.

7. Check for continuity with a tester.

NOTE:

D If there is no continuity, clean the terminals.
D Be sure to perform the steps 1 to 7 listed

above when checking the wireharness.

D For a field remedy, use a contact revitalizer

available on the market.

D Use the tester on the connector as shown.

1-6

HOW TO USE THE CONVERSION TABLE

EB201000

HOW TO USE THE CONVERSION TABLE

All specification data in this manual are listed in SI and METRIC UNITS.
Use this table to convert METRIC unit data to IMPERIAL unit data.
Ex.

METRIC MULTIPLIER IMP

**mm  0.03937 = ** in
2 mm  0.03937 = 0.08 in

CONVERSION TABLE

METRIC TO IMP

Known Multiplier Result

GEN

INFO

Torque

Weight

Distance

Volume/
Capacity

Miscella­neous

mSkg
mSkg
cmSkg
cmSkg

kg
g

km/hr
km
m
m
cm
mm

cc (cm3)

3

cc (cm
lit (liter)
lit (liter)

kg/mm
kg/cm
Centigrade

)

2

7.233

86.794

0.0723

0.8679

2.205

0.03527

0.6214

0.6214

3.281

1.094

0.3937

0.03937

0.03527

0.06102

0.8799

0.2199

55.997

14.2234
9/5(_C) + 32

ftSlb
inSlb
ftSlb
inSlb

lb
oz

mph
mi
ft
yd
in
in

oz (IMP liq.)
cuSin
qt (IMP liq.)
gal (IMP liq.)

lb/in

2

psi (lb/in
Fahrenheit (_F)

)

1-7

GEN

SPECIAL TOOLS

EB102000

SPECIAL TOOLS

The following special tools are necessary for complete and accurate tune-up and assembly.
Use only the appropriate special tools; this will help prevent damage caused by the use of inappropri­ate tools or improvised techniques.
When placing an order, refer to the list provided below to avoid any mistakes.

INFO

Tool No.

90890-01084

-01085

90890-01235 Rotor holding tool

90890-01268 Ringnut wrench

90890-01311 Valve adjusting tool

90890-01312 Fuel level gauge

Weight
Rocker arm shaft puller bolt

These tools are used when removing
or installing the rocker arm shafts.

This tool is used to remove the
flywheel magneto.

This tool is used to loosen and tighten
the exhaust and steering ringnut.

This tool is necessary for adjusting
valve clearance.

This gauge is used to measure the fuel
level in the float chamber.

Tool name/Usage Illustration

90890-01325

-01352

90890-01326

-04084

90890-01337

-01464

90890-01348 Locknut wrench

Radiator cap tester
Adaptor

These tools are used for checking the
cooling system.

T-handle
Damper rod holder

These tool are used for holding the
damper rod holder when removing or
installing the damper rod holder.

Clutch spring compressor
Clutch spring holder arm

These tools are used for removing the
nut with holding the compression spring.

This tool is used when removing or
installing the secondary sheave nut.

1-8

SPECIAL TOOLS

Tool No. Tool name/Usage Illustration

90890-01362 Flywheel puller

This tool is used for removing the
rotor.

GEN

INFO

90890-01367

-01368

90890-01384 Oil seal guide

90890-01403 Ring nut wrench

90890-01701 Sheave holder

90890-01996 Cylinder cup installer set

Fork seal driver weight
Fork seal driver attachment (ø33)

This tool is used when installing the
fork seal.

This tool is used for protecting the oil
seal lip when installing the secondary
sliding sheave.

This tool is used to loosen and tighten
the steering ring nut.

This tool is used for holding the
secondary sheave.

This tool is used for installing the
cylinder cup to the master cylinder
piston.

90890-03079 Thickness gauge

This tool is used to measure the valve
clearance.

90890-03081 Compression gauge

These tools are used to measure the
engine compression.

90890-03112 Pocket tester

These instruments are invaluable for
checking the electrical system.

90890-03113 Engine tachometer

This tool is needed for detecting
engine rpm.

1-9

SPECIAL TOOLS

Tool No. Tool name/Usage Illustration

90890-03141 Timing light

This tool is needed for detecting
ignition timing.

90890-04101 Valve lapper

This tool is used for removing and
installing the lifter and for lapping the
valve.

GEN

INFO

90890-04019

-04108

90890-04058

-04078

90890-06754 Ignition checker

90890-85505 Yamaha bond No. 1215

Valve spring compressor
Attachment

These tools are used when removing
or installing the valve and the valve
spring.

Middle shaft bearing driver
Mechanical seal installer

These tools are used for installing
mechanical seal.

This instrument is necessary for checking
the ignition system components.

This sealant (bond) is used for crankcase
mating surface, etc.

1-10

CHAPTER 2.

SPECIFICATIONS

GENERAL SPECIFICATIONS 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MAINTENANCE SPECIFICATIONS 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ENGINE 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS 2-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ELECTRICAL 2-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL TORQUE SPECIFICATIONS 2-16. . . . . . . . . . . . . . . . . . . . . . . . . .

LUBRICATION POINTS AND GRADE OF LUBRICANT 2-17. . . . . . . . . . . .

ENGINE 2-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS 2-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CABLE ROUTING 2-19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL SPECIFICATIONS

SPECIFICATIONS

GENERAL SPECIFICATIONS

Model YP250

Model code: 4UC 1 (except for CH, A)

4UD1 (for CH, A)

Dimensions:

Overall length
Overall width
Overall height
Seat height
Wheelbase
Minimum ground clearance
Minimum turning radius

Basic weight:

With oil and full fuel tank

Engine:

Engine type
Cylinder arrangement
Displacement
Bore  stroke
Compression ratio
Compression pressure (STD)
Starting system
Lubrication system:

2,110 mm

,750 mm

1,330 mm

,700 mm

1,500 mm

,115 mm

2,600 mm

158 kg

Liquid-cooled 4-stroke, SOHC
Forward-inclined single cylinder

3

0.249L (249 cm

69.0  66.8 mm
10 : 1
1,400 kPa (14 kg/cm
Electric starter
Wet sump

)

2

SPEC

, 14 bar) at 500 r/min

Oil type or grade:

Engine oil

Periodic oil change
Total amount

Transmission oil

Total amount

Radiator capacity

Total amount (including all routes)

Air filter: Carburetor side

Crankcase side

Fuel:

Type
Fuel tank capacity

API STANDERD:
SE or higher grade

1.2 L

1.4 L

0.25 L

1.4 L
Wet type element

Dry type element

Regular unleaded gasoline
11 L

2-1

GENERAL SPECIFICATIONS

Model YP250

Carburetor:

Type/quantity
Manufacturer

Spark plug:

Type
Manufacturer

Spark plug gap
Clutch type: Dry, centrifugal automatic
Transmission:

Primary reduction system

Primary reduction ratio

Secondary reduction sytem

Secondary reduction ratio

Transmission type

Operation

Single speed automatic
Chassis:

Frame type

Caster angle

Trail
Tire:

Type

Size front
rear

Manufacturer front
rear

Type front
rear

Tire pressure (cold tire):

Maximum load-except motorcycle

Loading condition A*

front

rear

Loading condition B*

front

rear

High-speed riding

front

rear

Y28V-1A/1
TEIKEI

DR8EA
NGK

0.6 X 0.7 mm

Helical gear
40/15 (2.666)
Sper gear
37/16 (2.312)
Single speed automatic (V-belt type)
Centrifugal automatic type

2.20 X 0.88:1

Steel tube underbone
28
103 mm

Tubeless
110/90-12 64J
130/70-12 62L
IRC/CHENG SHIN
IRC/CHENG SHIN
MB61/C922
MB61/C940

197 kg
0 X 90 kg

2

175 kPa (1.75 kg/cm
200 kPa (2.0 kg/cm

, 1.75 bar)

2

, 2.0 bar)
90 X 205 kg
200 kPa (2.0 kg/cm
225 kPa (2.25 kg/cm

200 kPa (2.0 kg/cm
250 kPa (2.5 kg/cm

2

, 2.0 bar)

2

, 2.25 bar)

2

, 2.0 bar)

2

, 2.5 bar)

SPEC

*Load is the total weight of cargo, rider, passenger, and accessories.

2-2

Model YP250

Brake:

Front brake type

operation

Rear brake type

operation

Suspension:

Front suspension
Rear suspension

Shock absorber:

Front shock absorber
Rear shock absorber

Wheel travel:

Front wheel travel
Rear wheel travel

Electrical:

Ignition system
Generator system
Battery type
Battery capacity

GENERAL SPECIFICATIONS

Single disc brake
Right hand operation
Drum brake
Left hand operation

Telescopic fork
Unit swing

Coil spring/Oil damper
Coil spring/Oil damper

85 mm
90 mm

T.C.I. (Digital)
A.C. magneto
GT7B-5
12 V 6 AH

SPEC

Headlight type: Quartz bulb (Halogen)
Bulb wattage  quantity:

Headlight
Marker light
Tail/brake light
Flasher light
Meter light

High beam indicator light
Oil indicator light
Turn indicator light

License light

12V 60 W/55 W  1
12V 4 W  1
12V 5 W/21 W  1
12V 21W  4
12V 1.7W  4
12V 3.4 W  1
12V 1.7 W  1
12V 3.4 W  2
12V 5 W  1

2-3

MAINTENANCE SPECIFICATIONS

MAINTENANCE SPECIFICATIONS

ENGINE

SPEC

Item
Cylinder head:

Warp limit

Cylinder:

Bore size
Out of round limit

Camshaft:

Cam dimensions

Intake “A”

“B”

“C”

Exhaust “A”

“B”

“C”

Camshaft runout limit

Cam chain:

Cam chain type/No. of links

Rocker arm/rocker armshaft:

Rocker arm inside diameter
Rocker shaft outside diameter
Rocker arm-to-rocker armshaft
clearance

Standard Limit

SSS 0.03 mm

69.000 X 69.005 mm

SSS

36.545 X 36.645 mm

30.021 X 30.121 mm

6.524 mm

36.547 X 36.647 mm

30.067 X 30.167 mm

6.48 mm

SSS

DID SCSA-0404A SDH/104 SSS

12.000 X 12.018 mm

11.981 X 11.991 mm

0.009 X 0.012 mm

69.1 mm

0.03 mm

36.45 mm

29.92 mm

SSS

36.45 mm

29.97 mm

SSS

0.03 mm

12.03 mm

11.995 mm

SSS

Valve, valve seat, valve guide:

Valve clearance (cold) IN

Valve dimensions

Face Width Seat Width Margin Thickness

“A” head diameter IN

“B” face width IN

“C” seat width IN

“D” margin thickness IN

Stem outside diameter IN

Guide inside diameter IN

EX

EX

EX

EX

EX

EX

EX

0.08 X 0.12 mm

0.16 X 0.20 mm

33.9 X 34.1 mm

28.4 X 28.6 mm

3.394 X 3.960 mm

3.394 X 3.960 mm

0.9 X 1.1 mm

0.9 X 1.1 mm

0.8 X 1.2 mm

0.8 X 1.2 mm

5.975 X 5.990 mm

5.960 X 5.975 mm

6.000 X 6.012 mm

6.000 X 6.012 mm

SSS
SSS

SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS

5.94 mm

5.92 mm

6.05 mm

6.05 mm

2-4

MAINTENANCE SPECIFICATIONS

Item Standard Limit

SPEC

Stem-to-guide clearance IN

EX
Stem runout limit
Valve seat width IN

EX

Valve spring:

Free length (Inner) IN/EX

Free length (Outer) IN/EX

Set length (valve closed) (Inner) IN/EX

Set length (valve closed) (Outer) IN/EX

Compressed pressure (Inner) IN/EX

(Outer) IN/EX
Tilt limit (Inner) IN/EX

Tilt limit (Outer) IN/EX

Piston:

Piston to cylinder
clearance
Piston size “D”
Measuring point “H”
Piston pin bore
inside diameter
Piston pin outside diameter

Piston rings:

Top ring:

Type
End gap (installed)
Side clearance (installed)

2nd ring:

Type
End gap (installed)
Side clearance

Oil ring:

End gap (installed)

0.010 X 0.037 mm

0.025 X 0.052 mm

SSS

0.9 X 1.1 mm

0.9 X 1.1 mm

38.1 mm

36.93 mm

30.1 mm

31.6 mm

7.8 X 9.0 kg

37.22 X 42.83 kg

SSS
SSS

0.02 X 0.04 mm

68.965 X 68.980 mm
5 mm

17.004 X 17.015 mm

16.991 X 17.000 mm

Barrel

0.15 X 0.30 mm

0.04 X 0.08 mm

Taper

0.30 X 0.45 mm

0.03 X 0.07 mm

0.2 X 0.7 mm

0.08 mm

0.1 mm

0.01 mm

1.6 mm

1.6 mm

36.1 mm

35.0 mm

SSS
SSS
SSS
SSS

2.5_/1.7 mm

2.5_/1.7 mm

0.15 mm

SSS
SSS

17.045 mm

16.975 mm

SSS

0.45 mm

0.12 mm

SSS

0.7 mm

0.12 mm

SSS

Crankshaft:

Crank width “A”
Runout limit “C”
Big end side clearance “D”

59.95 X 60.00 mm

0.03 mm

0.35 X 0.85 mm

2-5

SSS
SSS
SSS

MAINTENANCE SPECIFICATIONS

Item Standard Limit
Automatic centrifugal clutch:

Clutch shoe thickness
Clutch housing inside diameter
Clutch shoe spring free length
Weight outside diameter
Clutch – in revolution
Clutch – stall revolution

V-belt:

V-belt width

Carburetor:

Type
I.D. mark
Ventuly outside diameter
Main jet (M.J)
Main air jet (M.A.J)
Jet needle (J.N)
Throttle valve size (Th.V)
Pilot air jet (P.A.J.1)
Needle jet (N.J)
Pilot outlet (P.O)
Pilot jet (P.J)
Bypass (B.P)
Pilot screw (P.S)
Valve seat size (V.S)
Starter jet 1 (G.S.1)
Starter jet 2 (G.S.2)
Float height (F.H)

Engine idle speed

Intake vacuum
Oil temperature
Cooling water temperature

3.0 mm
135 mm

28.1 mm
20 mm
2,100 X 2,700 r/min
3,700 X 4,700 r/min

22.6 mm 21.0 mm

Y28V-1B-1
4UC 00 [4UD 00 (CH, A)]
ø28
#130
ø0.9
5D32-3/5
11_
ø1.2
ø2.585
ø0.8
#44

0.7 4
17/8

1.4
ø0.45
ø0.5
27 mm
1,450 X 1,550 r/min
220 X 260 mmHg
65 X 75_C
80_C

SPEC

2.0 mm

135.5 mm

SSS

19.5 mm

SSS
SSS

SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS
SSS

Fuel pump:

Type
Model/manufacturer

Oil pump:

Type
Tip clearance
Side clearance
Housing and rotor clearance

Vaccum type
4HC/MIKUNI

Trochoid type

0.1 X 0.34 mm

0.013 X 0.036 mm

0.04 X 0.09 mm

2-6

SSS
SSS

SSS

0.4 mm

0.15 mm

0.15 mm

2

,

SPEC

SSS
SSS

SSS
SSS
SSS

MAINTENANCE SPECIFICATIONS

Item Standard Limit
Radiator:

Type
Width/height/thickness
Radiator cap opening pressure

Radiator capacity
Reservoir tank capacity

Thermostatic valve:

Type/manufacturer
Valve opening temperature
Valve full open temperature
Valve full open lift

Item Size
Bearings and oil seals:

Big end bearing
Crankshaft bearing (left)
Crankshaft bearing (right)
Crankshaft oil seal (left)
Crankshaft oil seal (right)
Water pump bearing
Water pump oil seal
Main axle bearing (left)
Main axle bearing (right)
Drive axle bearing (left)
Drive axle bearing (right)
Drive axle oil seal
Camshaft bearing (left)
Camshaft bearing (right)
Primary drive gear bearing (left)
Primary drive gear bearing (right)
Primary drive gear oil seal

Cooling fin with electric fan
140/238/24 mm
110 X 140 kPa (1.1 X 1.4 kg/cm

1.1 X 1.4 bar)

1.4 L

0.35 L

4HC/NIHON THERMOSTAT

80.5 X 83.5_C
95_C
3 mm

32 40 20 (needle bearing)
6306
63/28
SD-30-45-5
S7-14-27-6
6000
S-10-21-5
15NQ2815
15NQ2815
6303
6272
SD8-32-52-7
6005
6202Z
6205
6302
SD8-32-52-7

2-7

TIGHTENING TORQUES

g

size

y

ENGINE

MAINTENANCE SPECIFICATIONS

SPEC

Part to be tightened

Oil check bolt
Exhaust pipe stud bolt
Spark plug
Cam sprocket cover
Cylinder head and cylinder
Cylinder head and cylinder
(Cam chain side)
Valve cover
Rotor
Valve adjuster locknut
Cam shaft bearing stopper
Cam sprocket
Cam chain tensioner

(Body)

(Plug)
Guide stopper 2
Water pump housing cover
Hose joint
Thermostatic valve cover
Filler neck supporting
Oil pump
Oil pump cover
Drain plug
Carburetor joint
Carburetor joint and carburetor
Air filter assembly
Air filter cover
Fuel pump
Exhaust pipe assembly
Muffler
Muffler and exhaust pipe
Protector (Muffler)
Protector (Exhaust pipe)
Crankcase (left and right)
Drain bolt
Oil filler
Transmission case cover
Crankcase cover (left)
Crankcase filter cover
Crankcase cover protector
Magnet cover

Part name

—
—
—

Bolt

Nut

Bolt

Bolt

Nut

Nut
Bolt
Bolt

Bolt
Bolt
Bolt
Bolt

—
Bolt
Bolt

Screw

Bolt
Bolt
Bolt

Nut

Bolt

Screw

—

Nut
Bolt
Bolt

Screw
Screw

Bolt
Bolt
Bolt
Bolt
Bolt

—

Bolt

—

Thread

M6
M8
M12
M6
M8
M6

M6
M16
M6
M6
M10

M6
M8
M6
M6
M6
M6
M5
M6
M3
M35
M6
M6
M6
M5
M6
M8
M10
M8
M6
M6
M6
M8
M14
M8
M6
M6
M6
M6

Q’ty

1
2
1
2
4
2

5
1
2
2
1

2
1
1
3
2
2
1
2
1
1
2
2
2
5
2
2
3
1
3
2
9
1
1
6

11

3
2

10

Tightening

torque

Nm mSkg

7

0.7
13
18
10
22
10

10
80
14

60

10

10
10

10

32
10
10

10
20
53
20
10
10
10
22

16
10

10

1.3

1.8

1.0

2.2

1.0

1.0

8.0

1.4

8

0.8

6.0

1.0

8

0.8

1.0

1.0

7

0.7

1.0

5

0.5

7

0.7

1

0.1

3.2

1.0

1.0

7

0.7

1

0.1

1.0

2.0

5.3

2.0

1.0

1.0

1.0

2.2

3

0.3

1.6

1.0

7

0.7

7

0.7

1.0

Remarks

2-8