Yamaha YW100 Service Manual

YW100

4VP-ME1

EB000000

YW100E

SERVICE MANUAL

©1999 by Yamaha Motor TAIWAN Co., Ltd.

1st Edition, March 1999

All rights reserved. Any reprinting or

unauthorized use without the written

permission of Yamaha Motor Taiwan Co., Ltd.

is expressly prohibited.

YP002000

HOW TO USE THIS MANUAL

MANUAL ORGANIZATION

This manual consists of chapters for the main categories of subjects. (See”Illustrated symbols”)
1st title 1: This is the title of the chapter with its symbol on the upper right corner of each page.
2nd title 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.

3rd title 3: This title indicates a sub-section that is followed by step-by-step procedures accom-

panied by corresponding illustrations.

EXPLODED DIAGRAMS

To help 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 4 is provided for disassembly and assembly jobs.

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

3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol
marks 6. The meanings of the symbol marks are given on the next page.

4. A job instruction chart 7 accompanies the exploded diagram, providing the order of jobs,
names of parts, notes in jobs, etc.

5. For jobs requiring more information, the step-by-step format supplements 8 are given in
addition to the exploded diagram and the job instruction chart.

5

6

7

2

1

4

3

8

INDEX

GENERAL INFORMATION

SPECIFICATIONS

PERIODIC INSPECTION AND

1

2

ADJUSTMENT

ENGINE OVERHAUL

CARBURETION

CHASSIS

ELECTRICAL

3

4

5

6

–+

TROUBLESHOOTING

7

8

12

GEN

SPEC

INFO

34

INSP

ENG

ADJ

56

COOL CARB

78

CHAS

ELEC

– +

EB003000

ILLUSTRATED SYMBOLS

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

1 General information
2 Specifications
3 Periodic inspection and adjustment
4 Engine
5 Cooling system
6 Carburetion
7 Chassis
8 Electrical
9 Troubleshooting

90

TRBL

SHTG

qw

er

T

.

R

.

tyu

iop

LS

G

M

M

E

asd

B

Illustrated symbols 0 to u are used to iden­tify the specifications appearing in the text.

0 Possible to maintain with engine mounted
q Filling fluid
w Lubricant
e Special tool
r Tightening
t Wear limit, clearance
y Engine speed
u Ω, V, A

Illustrated symbols i to d in the exploded dia-
grams indicate the types of lubricants and lu­brication points.

i Apply engine oil
o Apply gear oil
p Apply molybdenum disulfide oil
a Apply wheel bearing grease
s Apply lightweight lithium-soap base grease
d Apply molybdenum disulfide grease

fg

LT

New

Illustrated symbols f to g in the exploded
diagrams indicate the where to apply locking
agent f and when to install new parts g .

®

f Apply locking agent (LOCTITE
g Use new one

)

EB001000

NOTICE

This manual was produced by the Yamaha Motor Taiwan Company primarily for use by Yamaha/
MBK 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/MBK 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.

Yamaha Motor Taiwan Company, Ltd. is continually striving to improve all its models. Modifica­tions and significant changes in specifications or procedures will be forwarded to all authorized
Yamaha/MBK 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.

Q

w

cC

NOTE:

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

Failure to follow WARNING instructions
to the scooter operator, a bystander or a person inspecting or repairing the
scooter.

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

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

could result in severe injury or death

CHAPTER 1.

GENERAL INFORMATION

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

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

ENGINE SERIAL NUMBER ............................................................................................................ 1-2

IMPORTANT INFORMATION ............................................................................................................ 1-3

PREPARATION FOR REMOVAL PROCEDURES........................................................................... 1-3

REPLACEMENT PARTS ................................................................................................................. 1-3

GASKETS, OIL SEALS, AND O-RINGS ........................................................................................ 1-3

LOCK WASHERS/PLATES AND COTTER PINS ........................................................................... 1-3

BEARINGS AND OIL SEALS ......................................................................................................... 1-4

CIRCLIPS ........................................................................................................................................ 1-4

CHECKING OF CONNECTIONS ........................................................................................................ 1-5

HOW TO USE THE CONVERSION TABLE ....................................................................................... 1-6

SPECIAL TOOLS ................................................................................................................................ 1-7

CHAPTER 2.

SPECIFICATIONS

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

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

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

CHASSIS ........................................................................................................................................ 2-7

ELECTRICAL ................................................................................................................................... 2-9

GENERAL TORQUE SPECIFICATIONS........................................................................................... 2-11

LUBRICATION POINTS AND LUBRICANT TYPE ........................................................................... 2-12

ENGINE ........................................................................................................................................ 2-12

CHASSIS ...................................................................................................................................... 2-12

CABLE ROUTING ............................................................................................................................. 2-13

CHAPTER 3.

PERIODIC INSPECTION AND ADJUSTMENTS

NTRODUCTION ................................................................................................................................. 3-1

PERIODIC MAINTENANCE/ LUBRICATION INTERVALS ............................................................... 3-1

SIDECOVER AND SEAT ................................................................................................................ 3-3

JOB INSTRUCTION CHART .......................................................................................................... 3-3

LOWER COWLING ,UPPER COVER, LEG SHIELD1,2 AND FOOTREST BOARD ....................... 3-4

HANDLEBAR COVER(FRONT AND REAR)................................................................................... 3-5

ENGINE .............................................................................................................................................. 3-6

IDLING SPEED ADJUSTMENT ..................................................................................................... 3-6

THROTTLE CABLE FREE ADJUSTMENT ..................................................................................... 3-7

AUTOLUBE PUMP AIR BLEEDING ............................................................................................... 3-8

AUTOLUBE PUMP CABLE ADJUSTMENT .................................................................................. 3-8

SPARK PLUG INSPECTION........................................................................................................... 3-9

ENGINE OIL LEVEL INSPECTION ............................................................................................... 3-10

TRANSMISSION OIL REPLACEMENT ........................................................................................ 3-11

AIR FILTER ELEMENT CLEANING .............................................................................................. 3-12

V-BELT INSPECTION ................................................................................................................... 3-14

CHASSIS .......................................................................................................................................... 3-15

FRONT BRAKE LEVER FREE PLAY CHECK ................................................................................ 3-15

REAR BRAKE LEVER FREE PLAY CHECK................................................................................... 3-15

BRAKE PAD INSPECTION ........................................................................................................... 3-15

BRAKE SHOE INSPECTION ........................................................................................................ 3-16

BRAKE FLUID LEVEL INSPECTION ............................................................................................ 3-16

AIR BLEEDING(HYDRAULIC BRAKE SYSTEM) ......................................................................... 3-17

STEERING ADJUSTMENT .......................................................................................................... 3-18

TIRE INSPECTION........................................................................................................................ 3-19

WHEEL INSPECTION ................................................................................................................... 3-20

FRONT FORK INSPECTION......................................................................................................... 3-20

REAR SHOCK ABSORBER INSPECTION.................................................................................... 3-20

SEAT LOCK CABLE ADJUSTMENT ........................................................................................... 3-20

ELECTRICAL ..................................................................................................................................... 3-21

BATTERY INSPECTION ............................................................................................................... 3-21

FUSE INSPECTION ...................................................................................................................... 3-26

HEADLIGHT BEAM ADJUSTMENT ............................................................................................ 3-27

HEADLIGHT BULB REPLACEMENT............................................................................................ 3-27

TAILLIGHT BULB/REAR FLASHER BULB REPLACEMENT ....................................................... 3-28

TURN SIGNAL AND TAILLIGHT BULB REPLACEMENT ........................................................... 3-28

LICENCE LIGHT BULB REPLACEMENT...................................................................................... 3-29

CHAPTER 4.

ENGINE

ENGINE OVERHAUL ......................................................................................................................... 4-1

WIREHARNESS AND CABLES...................................................................................................... 4-1

CYLINDER HEAD, CYLINDER AND PISTON .................................................................................... 4-3

CYLINDER HEAD CYLINDER AND PISTON ................................................................................. 4-3

PISTON PIN AND PISTON REMOVAL .......................................................................................... 4-4

CYLINDER HEAD INSPECTION..................................................................................................... 4-4

CYLINDER AND PISTON INSPECTION ........................................................................................ 4-5

PISTON RINGS INSPECTION........................................................................................................ 4-7

PISTON PIN AND PISTON PIN BEARING .................................................................................... 4-7

PISTON PIN AND PISTON INSTALLATION ................................................................................. 4-8

CYLINDER AND CYLINDER HEAD ................................................................................................ 4-9

V-BELT, CLUTCH AND SECONDARY/PRIMARY SHAVE ............................................................. 4-11

KICK STARTER AND CRANKCASE COVER(LEFT)..................................................................... 4-11

KICK STARTER............................................................................................................................. 4-12

KICK STARTER INSTALLATION ................................................................................................. 4-13

V-BELT, CLUTCH AND SECONDARY/PRIMARY SHEAVE ........................................................ 4-14

SECONDARY SHEAVE ................................................................................................................ 4-15

PRIMARY SHEAVE REMOVAL.................................................................................................... 4-16

SECONDARY SHEAVE REMOVAL.............................................................................................. 4-16

CLUTCH INSPECTION ................................................................................................................. 4-17

V-BELT INSPECTION ................................................................................................................... 4-18

PRIMARY SHEAVE INSPECTION................................................................................................ 4-19

SECONDARY SHEAVE ................................................................................................................ 4-20

SECONDARY SHEAVE INSTALLATION ..................................................................................... 4-21

PRIMARY SHEAVE ...................................................................................................................... 4-22

STARTER CLUTCH AND STARTER MOTOR ................................................................................. 4-24

STARTER CLUTCH AND STARTER MOTOR.............................................................................. 4-24

STARTER CLUTCH AND GEARS ................................................................................................ 4-26

C.D.I. MAGNETO ............................................................................................................................. 4-27

C.D.I. MAGNETO ......................................................................................................................... 4-27

C.D.I. MAGNETO REMOVAL....................................................................................................... 4-28

C.D.I. MAGNETO INSTALLATION .............................................................................................. 4-28

AUTOLUBE PUMP ........................................................................................................................... 4-29

AUTOLUBE PUMP ....................................................................................................................... 4-29

AUTOLUBE PUMP INSTALLATION ........................................................................................... 4-30

TRANSMISSION .............................................................................................................................. 4-31

TRANSMISSION .......................................................................................................................... 4-31

CRANKCASE AND REED VALUE ................................................................................................... 4-33

CRANKCASE AND REED VALUE................................................................................................ 4-33

CRANKCASE(RIGHT)REMOVAL ................................................................................................. 4-35

REED VALVE INSPECTION ......................................................................................................... 4-35

CRANKCASE(RIGHT)INSTALLATION ........................................................................................ 4-36

CRANKSHAFT .................................................................................................................................. 4-38

CRANKSHAFT .............................................................................................................................. 4-38

CRANKSHAFT REMOVAL ........................................................................................................... 4-39

CRANKSHAFT INSPECTION ....................................................................................................... 4-39

CRANKSHAFT INSTLLATION ..................................................................................................... 4-40

CHAPTER 5

CARBURETION

CARBURETION .................................................................................................................................. 5-1

CARBURETOR................................................................................................................................ 5-1

CARBURETOR DISASSEMBLY ..................................................................................................... 5-2

CARBURETOR INSPECTION ......................................................................................................... 5-3

CARBURETOR ASSEMBLY ........................................................................................................... 5-3

FUEL LEVEL ADJUSTMENT ......................................................................................................... 5-4

AUTO CHOKE INSPECTION.......................................................................................................... 5-5

FUEL COCK INSPECTION ............................................................................................................. 5-6

CHAPTER 6

CHASSIS

FRONT WHEEL AND BRAKE DISC ................................................................................................... 6-1

FRONT WHEEL AND BRAKE DISC ............................................................................................... 6-1

FRONT WHEEL DISASSEMBLY .................................................................................................... 6-2

FRONT WHEEL DISASSEMBLY .................................................................................................... 6-3

FRONT WHEEL INSPECTION........................................................................................................ 6-3

BRAKE DISC INSPECTION ............................................................................................................ 6-4

FRONT WHEEL ASSEMBLY.......................................................................................................... 6-4

FRONT WHEEL INSTALLATION ................................................................................................... 6-5

WHEEL STATIC BALANCE ADJUSTMENT.................................................................................. 6-6

FRONT BRAKE ................................................................................................................................... 6-8

BRAKE PAD .................................................................................................................................... 6-8

BRAKE PAD REPLACEMENT ........................................................................................................ 6-9

MASTER CYLINDER ........................................................................................................................ 6-12

MASTER CYLINDER DISASSEMBLY ............................................................................................. 6-13

MASTER CYLINDER INSPECTION.............................................................................................. 6-14

MASTER CYLINDER ASSEMBLY................................................................................................ 6-14

MASTER CYLINDER INSTALLATION ......................................................................................... 6-15

CALIPER ........................................................................................................................................... 6-17

CALIPER DISASSEMBLY................................................................................................................. 6-18

BRAKE CALIPER DISASSEMBLY................................................................................................ 6-19

CALIPER INSPECTION................................................................................................................. 6-19

BRAKE CALIPER ASSEMBLY...................................................................................................... 6-20

CALIPER INSTALLATION ............................................................................................................ 6-20

REAR WHEEL AND REAR BRAKE .................................................................................................. 6-21

REAR WHEEL AND REAR BRAKE............................................................................................... 6-21

REAR WHEEL ............................................................................................................................... 6-21

REAR BRAKE................................................................................................................................ 6-22

REAR WHEEL INSPECTION ........................................................................................................ 6-23

REAR BRAKE INSPECTION ......................................................................................................... 6-23

REAR BRAKE INSTALLATION .................................................................................................... 6-24

HANDLEBAR .................................................................................................................................... 6-25

HANDLEBAR ................................................................................................................................ 6-25

HANDLEBAR INSTALLATION ..................................................................................................... 6-27

STEERING ........................................................................................................................................ 6-29

STEERING .................................................................................................................................... 6-29

STEERING REMOVAL ................................................................................................................. 6-30

STEERING INSPCTION................................................................................................................6-31

STEERING INSTALLATION ......................................................................................................... 6-31

FRONT FORK ................................................................................................................................... 6-34

FRONT FORK ...............................................................................................................................6-34

FRONT FORK DISASSEMBLY......................................................................................................... 6-35

FRONT FORK REMOVAL.............................................................................................................6-36

FRONT FORK DISASSEMBLY .....................................................................................................6-36

FRONT FORK INSPECTION.........................................................................................................6-37

FRONT FORK ASSEMBLY...........................................................................................................6-37

FRONT FORK INSTALLATION ....................................................................................................6-39

CHAPTER 7

ELECTRICAL

ELECTRICAL COMPONENTS ........................................................................................................... 7-1

CIRCUIT DIAGRAM....................................................................................................................... 7-2

CHECKING SWITCHES ..................................................................................................................... 7-4

CHECKING STEPS ........................................................................................................................ 7-4

SWITCH CONNECTION AS SHOWN IN THIS MANUAL ............................................................... 7-4

SWITCH POSITION AND TERMINAL CONNECTION ..................................................................... 7-5

IGNITION SYSTEM ........................................................................................................................... 7-6

CIRCUIT DIAGRAM....................................................................................................................... 7-6

TROUBLESHOOTING ................................................................................................................... 7-7

CHARGING SYSTEM ...................................................................................................................... 7-10

CIRCUIT DIAGRAM..................................................................................................................... 7-10

TROUBLE SHOOTING ................................................................................................................ 7-11

ELECTRIC STARTING SYSTEM ..................................................................................................... 7-14

CIRCUIT DIAGRAM..................................................................................................................... 7-14

TROUBLE SHOOTING ................................................................................................................ 7-15

STARTER MOTOR .......................................................................................................................... 7-19

STARTER DISASSEMBLY .......................................................................................................... 7-20

JOB INSTRUCTION CHART ....................................................................................................... 7-20

INSPECTION AND REPAIR......................................................................................................... 7-21

LIGHTING SYSTEM ........................................................................................................................ 7-23

CIRCUIT DIAGRAM..................................................................................................................... 7-23

TROUBLESHOOTING ................................................................................................................. 7-24

SIGNAL SYSTEM............................................................................................................................ 7-29

CIRCUIT DIAGRAM..................................................................................................................... 7-29

TROUBLESHOOTING ................................................................................................................. 7-30

SIGNAL SYSTEM CHECK........................................................................................................... 7-32

AUTO CHOKE SYSTEM ................................................................................................................. 7-38

CIRCUIT DIAGRAM..................................................................................................................... 7-38

TROUBLESHOOTING ................................................................................................................. 7-39

CHAPTER 8

TROUBLESHOOTING

STARTING FAILURE/HARD STARTING........................................................................................... 8-1

FUEL SYSTEM ............................................................................................................................... 8-1

IGNITION SYSTEM ........................................................................................................................ 8-2

COMPRESSION SYSTEM ............................................................................................................. 8-2

POOR IDLE SPEED PERFORMANCE ................................................................................................ 8-3

POOR IDLE SPEED PERFORMANCE ............................................................................................ 8-3

POOR MEDIUM AND HIGH SPEED PERFORMANCE...................................................................... 8-3

POOR MEDIUM AND HIGH SPEED PERFORMANCE .................................................................. 8-3

FAULTY AUTOMATIC(V-BELT TYPE) .............................................................................................. 8-4

SCOOTER DOES NOT MOVE WHILE ENGINE IS OPERATING .................................................. 8-4

CLUTCH OUT FAILURE ................................................................................................................. 8-4

POOR STANDING START(LOW CLIMBING ABILITY) ................................................................. 8-4

POOR ACCELERATION(POOR HIGH SPEED) .............................................................................. 8-4

OVERHEAT/POOR SPEED ................................................................................................................ 8-5

OVERHEAT ..................................................................................................................................... 8-5

POOR SPEED ..................................................................................................................................... 8-5

POOR SPEED ................................................................................................................................. 8-5

IMPROPER KICKING .......................................................................................................................... 8-6

SLIPPING ........................................................................................................................................ 8-6

HARD KICKING .............................................................................................................................. 8-6

KICK CRANK NOT RETURNING ................................................................................................... 8-6

FAULTY BRAKE ................................................................................................................................. 8-7

POOR BRAKING EFFECT............................................................................................................... 8-7

MALFUNCTION ............................................................................................................................. 8-7

INSATABLE HANDLING .................................................................................................................... 8-8

INSATABLE HANDLING ................................................................................................................ 8-8

FAULTY SIGNAL AND LIGHTING SYSTEM .................................................................................... 8-9

HEADLIGHT DARK......................................................................................................................... 8-9

BULB BURNT OUT ........................................................................................................................ 8-9

FLASHER DOES NOT BLINK......................................................................................................... 8-9

FLASHER KEEPS ON ..................................................................................................................... 8-9

FLASHER BLINKS SLOWER........................................................................................................ 8-10

FLASHER BLINKS QUICKER ....................................................................................................... 8-10

HORN DOES NOT SOUND ......................................................................................................... 8-10

WIRING DIAGRAM

1

SCOOTER INDENTIFICATION

GENERAL INFORMATION

SCOOTER IDENTIFICATION

FRAME SERIAL NUMBER

The frame serial number 1 is stamped into the
plate on the frame.

Initial serial number:

YW100E1(I)

*LPRSB0210*
*00000101*

YW100E1(F)

*LPRSB0210*
*00000101*

YW100E2(I)

*LPRSB0220*
*00100101*

YW100E2(F)

*LPRSB0220*
*00100101*

YW100E3(G)

*LPRSB0210*
*00300101*

YW100E4(G)

*LPRSB0220*
*00400101*

YW100E5(P)

*LPRSB0210*
*00200101*

YW100E5(Es)

*LPRSB0210*
*00200101*

YW100E6(A)

*LPRSB0210*
*00500101*

YW100E7(Che)

*LPRSB0210*
*00600101*

YW100E8(Che)

*LPRSB0220*
*00700101*

GEN

INFO

1-1

SCOOTER INDENTIFICATION

ENGINE SERIAL NUMBER

1

The engine serial number 1 is stamped into
the transmission case.

Initial serial number:

YW100E1(I,F):

B103E-000101

YW100E2(I,F):

B103E-100101

YW100E3(G):

B103E-300101

YW100E4(G):

B103E-400101

YW100E5(P,S):

B103E-200101

YW100E6(A):

B103E-500101

YW100E7(Che):

B103E-600101

YW100E8(Che):

B103E-700101

GEN

INFO

1-2

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.

300-008

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

GEN

INFO

300-016

EB101010

REPLACEMENT PARTS

1. Use only genuine Yamaha parts for all re­placements. Use oil and grease recom­mended by Yamaha 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.

1-3

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.

1 Lock washer

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.

GEN

INFO

1 Oil seal

cC

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

1 Bearing

EB101050

CIRCLIPS

1. Check all circlips carefully before reassem­bly. Always replace piston pin clips after
one use. Replace distorted circlips. When
installing a circlip 1 , make sure that the
sharp-edged corner 2 is positioned op­posite the thrust 3 it receives. See sec­tional view.

1-4

4 Shaft

IMPORTANT INFORMATION

EB801000

CHECKING OF CONNECTIONS

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

1. Disconnect:
8 Connector

2. Dry each terminal with an air blower.

3. Connect and disconnect the connector two
or three.

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

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

GEN

INFO

6. Connect:
8 Connector

NOTE:

The two connectors “click” together.

7. Check for continuity with a tester.

NOTE:

8 If there is no continuity, clean the termi-

nals.

8 Be sure to perform the steps 1 to 7 listed

above when checking the wireharness.

8 For a field remedy, use a contact revitalizer

available on the market.

8 Use the tester on the connector as shown.

1-5

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 = 0.083 in

CONVERSION TABLE

METRIC TO IMP

Known Multiplier Result

Torque

Weight

Distance

Volume/
Capacity

Miscellaneous

m.kg
m.kg
cm.kg
cm.kg

kg
g

km/h
km
m
m
cm
mm

3

)

cc(cm

3

)

cc(cm
lit(liter)
lit(liter)

kg/mm

2

kg/cm
Centigrade

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

ft.lb
in.lb
ft.lb
in.lb

lb
oz

mph
mi
ft
yd
in
in

oz (IMP liq.)
cu.in
qt(IMP liq.)
gal(IMP liq.)

lb/in
psi(lb/in
Fahrenheit (°F)

2

)

GEN

INFO

1-6

GEN

SPECIAL TOOLS

EE102000

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.

90890-01235

90890-01268

90890-01337

90890 -01274

-01275

-01277

-01288

90890-01189

90890- 01135

Tool name / Usage

Rotor holding tool

This tool is used to remove the flywheel
magneto.

Ringnut wrench

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

Clutch spring compressor

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

Crankshaft Installer pot 1
Crankshaft Installer bolt 2
Adapter 3 ,Spacer 4
These tools are used to install the crank­shaft.

Flywheel puller

This tool is used for removing the rotor.
Crankcase Separating tool

Illustration

90890-01384

90890-01403

90890-01701

90890-03079

This tool is used to remove the crankshaft
or separate the crankcase.

Oil seal guide

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

Ring nut wrench

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

Sheave holder

This tool is used for holding the secondary
sheave.

Thickness gauge

This tool is used to measure the clearance

1-7

SPECIAL TOOLS

GEN

INFO

Tool No.

90890-03112

90890-03113

90890-01409

90890-01410

90890-06754

90890-85505

Tool name / Usage

Pocket tester

These instruments are invaluable for check­ing the electrical system.

Engine tachometer

This tool is needed for detecting engine
rpm.

Oil seal guide

This tool is used to install the left side crank­case oil seal.

Oil seal installer

This tool is used to install the left side crank­case oil seal.

Ignition checker

This instrument is necessary for checking
the ignition system components.

Yamaha bond No. 1215

Illustration

90890-01348

90890-01367 1

-01400 2

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

Locknut wrench

This tool is used to loosen and tighten the
clutch carrier locknut of the secondary
sheave.

Front fork seal driver
Weight 1
Adapter 2

These tools are used when installing the
fork seal.

1 2

1-8

GENERAL SPECIFICATION

GENERAL SPECIFICATION

SPECIFICATION

SPEC

Model

Model code:
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
Starting system
Lubrication system:

Oil Type or Grade:

Engine Oil

Transmission Oil
Oil Capacity:

Oil Tank (Engine Oil)
Transmission Oil:
Periodic Oil Change

Total Amount
Air Filter:
Fuel:

Type

Tank Capacity
Carburetor:

Type / Manufacturer

YW100E1/2/3/4/5/6/7/8

4VPB/F/G/H/J/K/L/M

1,890mm
660mm
1,115mm
765mm
1,270mm
119mm
1,800mm

96kg

Air cooled 2 strcke, gasoline torque induction
Forward- inclined single cylinder

3

101cm

52.0 × 47.6 mm

6.6:1
Electric and kick starter
Separate lubrication

For YAMAHA brand:
Yamalube 2 or Air cooled 2-stroke engine oil (JASO
FC grade or ISO EG-C, EG-D grade)
For MBK brand:
Semi synthetic oil in accordance to the API TS3
standard
SAE 85W/140

1.4L

0.11L

0.13L
Wet type element

Regular unleaded gasoline

5.7L

VM16SS/MIKUNI

2-1

GENERAL SPECIFICATION

SPEC

Model

Spark Plug:

Type/Manufacturer

Gap
Clutch Type
Transmission:

Primary Reduction System

Primary Reduction Ratio

Secondary Reduction System

Secondary Reduction Ratio

Transmission Type

Operation
Chassis:

Frame type

Caster angle

Trail
Tire:

Type

Size front

rear

Manufacturer front

rear

Type front

rear

Maximum load*
Cold tire Pressure:

Up to 90 kg

Front
Rear

90 kgload~Maximum load*

Front
Rear

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

YW100E1/2/3/4/5/6/7/8

BPR7HS/NGK

0.9 ~ 1.0 mm
Dry, Centrifugal automatic

Herical gear
47/15 (3.133)
Spur gear
43/13 (3.308)
V-belt
Automatic

Steel tube underbone
26˚
86mm

Tubeless
120/90-10
130/90-10
CHENG SHIN
CHENG SHIN
56J
59J

160 kg

2

200kpa(2.0 kg/cm
200kpa(2.0 kg/cm

200kpa(2.0 kg/cm
200kpa(2.0 kg/cm

, 2.0 bar)

2

, 2.0 bar)

2

, 2.0 bar)

2

, 2.0 bar)

Single disc brake
Right hand operation
Drum brake
Left hand operation

Telescopic fork
Unit swing

Coil spring/oil damper
Coil spring/oil damper

70 mm
55 mm

C.D.I
Flywheel Magneto
YTX5L-BS
12V 4AH

2-2

GENERAL SPECIFICATION

SPEC

Model

Headlight type:
Bulb wattage x quantity:

Headlight

Tail/brake light

Flasher light

Auxiliary light

Licence plate light

Meter light

High beam indicator light
Oil indicator light
Turn indicator light

YW100E1/2/3/4/5/6/7/8

Bulb S1

25W/25W×2
5W/21W×1
10W×4
5W×2
5W×1

3.4W×1/1.7W×1

1.7W×1

1.7W×1

1.7W×1

2-3

MAINTENANCE SPECIFICATION

MAINTENANCE SPECIFICATION

ENGINE

SPEC

Item

Cylinder head:

Warp limit

*Lines indicate straightedge measurement
Cylinder:

Bore size

Taper limit

Out of round limit
Piston:

Piston to cylinder

clearance

Piston size “D”

Measuring point “H”

Oversize 1st

2nd
Piston pin bore
inside diameter
Piston pin outside diameter

Piston Ring:

Sectional Sketch (B × T)/Type

Top Ring
2nd Ring

End Gap (Installed):

Top Ring
2nd Ring

Side Clearance ( Installed):

Top Ring
2nd Ring

Crankshaft:

D

Standard

...

52.002~52.012
...
...

0.044~0.045 mm

51.958~51.967 mm

H

10 mm

52.52 mm

52.50 mm

14.004~14.015 mm

13.996~14.000 mm

1.2 × 2.05 mm/keystone

1.2 × 2.05 mm/keystone

0.15~0.35 mm

0.15~0.35 mm

0.03~0.05 mm

0.03~0.05 mm

Limit

0.05 mm

52.10 mm

0.05 mm

0.03 mm

0.10 mm
...
...
...
...
...

14.045 mm

13.975 mm

0.10 mm

0.10 mm

0.60 mm

0.60 mm

Crank Width “A”
Run Out Limit “C”
Connecting Rod Big End Side

Clearance “D”

Small End Free Play “F”

37.90~37.95 mm

0.03 mm

0.2~0.5 mm

0.4~0.8 mm

2-4

...
...

1.0 mm
...

MAINTENANCE SPECIFICATION

SPEC

Item

Automatic centrifugal clutch:

Clutch shoe thickness
Clutch housing inside diameter
Clutch shoe spring free length
Clutch - in revolution
Clutch - stall revolution

V-belt:

V-belt width

Transmission:

Main Axle Runout Limit
Drive Axle Runout Limit

Kick Starter:

Type
Kick Clip Tension

Carburetor:

I.D. Mark
Main Jet (M .J .)
Main nozzle (NJ)

Jet Needle-clip Position (J.N.)

Main Air Jet ( M .A .J .)
Cutaway (C.A.)
Pilot Jet (P.J.)
Pilot Air Screw (A.S .)
Valve Seat Size (V.S.)
Starter Jet (G .S.)
Float Height
Fuel level height
Engine Idling Speed

Reed Valve:

Valve Stopper Height
Reed Valve Clearance

Standard

4.0 mm
112 mm

26.2 mm
2,800~3,400 r/min
4,500~5,500 r/min

17.7 mm

0.08 mm

0.08 mm

Ratchet type
150~250 g

4VP-30 (4VPL/M:4VP-40)
#75
E-3
4DM7-3
ø0.7

3.5
#32.5
1and1/4±1/4
ø1.5
#30

16.5 mm

3.0~4.0 mm
1,750~1,850 r/min

6.0~6.4 mm
Less than 0.2 mm

Limit

2.5 mm

122.5 mm
...
...
...

16.0 mm

2-5

TIGHTENING TORQUES

LT

LT

LT

ENGINE

MAINTENANCE SPECIFICATION

Tightening

Part name

Thread

size

Q’ty RemarksPart to be tightened

Nm m•kg

SPEC

torque

Spark plug
Cylinder head and cylinder
Cylinder
Air shroud 3
Air shroud 1×3
Fan
Autolube pump
Reed valve
Air filter
Carburetor cap
Exhaust pipe
Muffler
Exhaust protector
Cap and pipe
Exhaust cover
Crankcase 1×2
Crankcase cover 2
Crankcase cover 1
Air duct
Crankcase holder
Drain bolt
Oil plug
Idle gear plate
Kick crank
Starter motor
Clutch housing
Primary sheeve
Magnet base
Magnet rotor

—
Nut
Stud bolt
Screw
Screw
Screw
Screw
Bolt
Screw
Screw
Screw
Bolt
Bolt
Bolt
Bolt
Bolt
Bolt
Bolt
Screw
Screw
Bolt
Plug
Screw
Bolt
Bolt
Nut
Nut
Screw
Nut

M 14
M 7
M 7
M 6

6.0
M 6
M 5
M 6
M 6
M 4
M 6
M 8
M 6
M 6
M6
M 6
M 6
M 6
M 6
M 6
M 8
M 14
M 6
M 6
M 6
M 10
M 12
M 6
M 12

1
4
4
3
1
3
2
4
1
2
2
2
3
3
5
6
6

12

2
2
1
1
2
1
2
1
1
2
1

20
14
17

7
2
7
4

11

9
2
9

26

9
11
13
12
12
12

7

7
18

3

8

9
13
40
45

8
43

2.0

1.4

1.7

0.7

0.2

0.7

0.4

1.1

0.9

0.2

0.9

2.6

0.9

1.1

1.3

1.2

1.2

1.2

0.7

0.7

1.8

0.3

0.8

0.9

1.3

4.0

4.5

0.8

4.3

2-6

CHASSIS

MAINTENANCE SPECIFICATION

SPEC

Item

Steering system:

Steering bearing type
No /size of steel balls: Upper

Lower

Front suspension:

Front fork travel
Fork free length
Fork length (Installed)
Spring rate (K1)

(K2)
Oil capacity
Oil grade
Inner tube vend limit

Rear suspension:

Shock absorber stroke
Shock absorber free length (Installed)
Spring free length (Installed)
Spring rate (K1)

Front wheel:

Type
Rim size
Rim material
Rim runout limit radial

lateral

Rear wheel:

Type
Rim size
Rim material
Rim runout limit radial

lateral

Front disc brake:

Type
Disc outside diameter × thickness
Pad thickness
Master cylinder inside diameter
Caliper cylinder outside diameter
Brake fluid type

Rear drum brake:

Type
Drum inside diameter
Shoe thickness

Brake lever:

Brake lever free play (front at lever side)
Brake lever free play (rear)
Throttle cable free play

Standard

Ball bearing
22 pcs
19 pcs

70 mm

350.8 mm

212.1 mm

15.68 Nm/mm(1.6 kg/mm)

23.5 Nm/mm(2.43 kg/mm)
88 c.c
Fork oil 10W or equivalent
...

55 mm

281.8 mm

159.8 mm

71.15 N/mm(7.26 kg/mm)

Cast wheel
MT3.50×10
Aluminum
...
...

Cast wheel
MT3.50×10
Aluminum
...
...

Single
180×4.0
6 mm
11 mm

34.93 mm
DOT #4

Leading, trailing
130 mm
4 mm

2~5 mm
10~20 mm
3~5 mm

Limit

...
...
...

...

212.1 mm
...
...
...
...

0.2 mm

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

...
...
...
...
1 mm
1 mm

...
...
...
1 mm
1 mm

...
180×3.5 mm

0.8 mm
...
...
...

...
131 mm
2 mm

...
...
...

2-7

TIGHTENING TORQUES

LT

CHASSIS

Part to be tightened

MAINTENANCE SPECIFICATION

Tightening

Thread

size

torque

Nm m•kg

SPEC

Remarks

Frame and engine bracket
Engine bracket, compression rod and engine
Protect bar
Rear grip
Sidestand
Rear shock absorber and frame
Rear shock absorber and engine
Steering ring nut
Handle holder and steering shaft
Brake hose and master cylinder
Fuel tank
Fuel cock
Fuel sender
Box
Seat lock assembly
Plastic parts & cover
Footrest board
Front wheel axle and nut
Rear wheel axle and nut
Rear brake cam lever
Front brake caliper and front fork
Brake disc and hub
Brake hose and front fork(lower)-bolt
Brake hose and front fork(lower)-nut
Brake hose and front fork(upper)-bolt
Brake caliper and bleed screw

M 12
M 10
M 6
M 6
M 10
M 10
M 8
M 25
M 10
M 8
M 6
M 6
M 5
M 6
M 6
M 5
M 6
M 10
M 14
M 6
M 8
M10
M 6
M 6
M 6
M 5

84
45
10
13
55
30
16
22
43
20
10

7
4
4
7
2
7

70

120

10
23
20

5

11

7
6

8.4

4.5

1.0

1.3

5.5

3.0

1.6

2.2

4.3

2.0

1.0

0.7

0.4

0.7

0.7

0.2

0.7

7.0

12.0

1.0

2.3

2.0

0.5

1.1

0.7

0.6

See
”page6-29”

2-8