YFM660FP

SERVICEMANUAL

LIT-11616-15-01

5KM-28197-E0

YFM660FP

SERVICE MANUAL

©2001 by Yamaha Motor Corporation, U.S.A.

First edition, May 2001

All rights reserved.

Any reproduction or unauthorized use

without the written permission of

Yamaha Motor Corporation, U.S.A.

is expressly prohibited.

Printed in U.S.A.

LIT-11616-15-01

EB001000

NOTICE

This manual was produced by the Yamaha 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 machine has a basic understanding of the mechanical ideas and the procedures of

machine repair. Repairs attempted by anyone without this knowledge are likely to render the

machine unsafe and unfit for use.

Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and sig-

nificant changes in specifications or procedures will be forwarded to all authorized Yamaha 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

to the machine operator, a bystander or a person inspecting or repairing the

machine.

A CAUTION indicates special precautions that must be taken to avoid dam-

age to the machine.

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

WARNING

CAUTION:

NOTE:

EB002000

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 in 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 accompa-

nied by corresponding illustrations.

EXPLODED DIAGRAMS

To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each

removal and disassembly section.

1. An easy-to-see exploded diagram 4 is provided for removal and disassembly jobs.

2. Numbers 5 are given in the order of the 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.

EB003000

ILLUSTRATED SYMBOLS

Illustrated symbols 1 to 0 are printed on the

top right of each page and indicate the subject

of each chapter.

1 General information

2 Specifications

3 Periodic checks and adjustments

4 Engine

5 Cooling system

6 Carburetion

7 Drive train

8 Chassis

9 Electrical

0 Troubleshooting

Illustrated symbols A to H are used to identify

the specifications appearing in the text.

A Can be serviced with engine mounted

B Filling fluid

C Lubricant

D Special tool

E Torque

F Wear limit, clearance

G Engine speed

H Ω, V, A

Illustrated symbols I to N in the exploded

diagrams indicate the types of lubricants and

lubrication points.

I Apply engine oil

J Apply gear oil

K Apply molybdenum disulfide oil

L Apply wheel bearing grease

M Apply lightweight lithium-soap base grease

N Apply molybdenum disulfide grease

Illustrated symbols O to P in the exploded

diagrams indicate where to apply a locking

agent O and when to install a new part P.

O Apply the locking agent (LOCTITE^)

P Replace

1

2

3

4

5

6

7

8

9

0

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

GEN

INFO

SPEC

CHK

ADJ

ENG

COOL

CARB

DRIV

CHAS

–

+

ELEC

TRBL

SHTG

T R

.

.

E

G

M

B

LS

M

LT

New

TABLE OF CONTENTS

GENERAL INFORMATION

GEN

INFO 1

SPECIFICATIONS

SPEC 2

PERIODIC CHECKS AND

ADJUSTMENTS

CHK

ADJ 3

ENGINE

ENG 4

COOLING SYSTEM

COOL 5

CARBURETION

CARB 6

DRIVE TRAIN

DRIV 7

CHASSIS

CHAS 8

ELECTRICAL

ELEC 9

TROUBLESHOOTING

TRBL

SHTG 10

–

+

CONTENTS

CHAPTER 1.

GENERAL INFORMATION

MACHINE IDENTIFICATION ........................................................................ 1-1

VEHICLE IDENTIFICATION NUMBER ................................................. 1-1

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

FEATURES ................................................................................................... 1-2

FRONT DIFFERENTIAL ........................................................................ 1-2

TRANSMISSION ................................................................................... 1-9

IMPORTANT INFORMATION ..................................................................... 1-10

PREPARATION FOR REMOVAL PROCEDURES ............................. 1-10

REPLACEMENT PARTS ..................................................................... 1-10

GASKETS, OIL SEALS AND O-RINGS .............................................. 1-10

LOCK WASHERS/PLATES AND COTTER PINS ............................... 1-11

BEARINGS AND OIL SEALS .............................................................. 1-11

CIRCLIPS ............................................................................................ 1-11

CHECKING OF CONNECTIONS ................................................................ 1-12

SPECIAL TOOLS ........................................................................................ 1-13

CHAPTER 2.

SPECIFICATIONS

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

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

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

CHASSIS ............................................................................................. 2-14

ELECTRICAL ...................................................................................... 2-18

HOW TO USE THE CONVERSION TABLE ............................................... 2-20

GENERAL TORQUE SPECIFICATIONS ................................................... 2-20

LUBRICATION POINTS AND LUBRICANT TYPES .................................. 2-21

ENGINE ............................................................................................... 2-21

COOLANT FLOW DIAGRAMS ................................................................... 2-22

OIL FLOW DIAGRAMS ..............................................................................2-24

CABLE ROUTING ....................................................................................... 2-27

CHAPTER 3.

PERIODIC CHECKS AND ADJUSTMENTS

INTRODUCTION ........................................................................................... 3-1

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

SEAT, CARRIERS, FENDERS AND FUEL TANK ....................................... 3-3

SEAT AND SIDE PANELS .................................................................... 3-3

FRONT CARRIER, FRONT BUMPER AND FRONT GRILL ................. 3-4

HANDLEBAR COVER, FUEL TANK COVER AND FRONT FENDER . 3-5

REAR CARRIER AND REAR FENDER ................................................ 3-7

ENGINE SKID PLATE (CENTER) AND ENGINE SKID PLATE

(REAR) .............................................................................................. 3-9

FUEL TANK ......................................................................................... 3-10

FOOTREST BOARDS ................................................................................ 3-12

ENGINE ....................................................................................................... 3-13

ADJUSTING THE VALVE CLEARANCE ............................................ 3-13

ADJUSTING THE TIMING CHAIN ...................................................... 3-16

ADJUSTING THE IDLING SPEED ...................................................... 3-16

ADJUSTING THE THROTTLE LEVER FREE PLAY .......................... 3-17

ADJUSTING THE SPEED LIMITER .................................................... 3-19

ADJUSTING THE STARTER CABLE ................................................. 3-21

CHECKING THE SPARK PLUG .........................................................3-22

CHECKING THE IGNITION TIMING ................................................... 3-23

MEASURING THE COMPRESSION PRESSURE .............................. 3-24

CHECKING THE ENGINE OIL LEVEL ................................................ 3-26

CHANGING THE ENGINE OIL ........................................................... 3-27

CLEANING THE AIR FILTER .............................................................. 3-29

CHECKING THE COOLANT LEVEL ................................................... 3-31

CHANGING THE COOLANT ............................................................... 3-32

CHECKING THE V-BELT .................................................................... 3-36

CLEANING THE SPARK ARRESTER ................................................ 3-37

CHASSIS .................................................................................................... 3-39

ADJUSTING THE REAR BRAKE ........................................................ 3-39

CHECKING THE BRAKE FLUID LEVEL ............................................. 3-41

CHECKING THE FRONT BRAKE PAD .............................................. 3-43

CHECKING THE REAR BRAKE PAD ................................................. 3-43

CHECKING THE BRAKE HOSE .........................................................3-43

BLEEDING THE HYDRAULIC BRAKE SYSTEM ............................... 3-44

ADJUSTING THE SELECT LEVER CONTROL CABLE

AND SHIFT ROD ............................................................................. 3-46

ADJUSTING THE REAR BRAKE LIGHT SWITCH ............................. 3-47

CHECKING THE FINAL GEAR OIL LEVEL ........................................ 3-48

CHANGING THE FINAL GEAR OIL .................................................... 3-48

CHECKING THE DIFFERENTIAL GEAR OIL ..................................... 3-49

CHANGING THE DIFFERENTIAL GEAR OIL ....................................3-50

CHECKING THE CONSTANT VELOCITY JOINT DUST BOOT ........ 3-51

CHECKING THE STEERING SYSTEM .............................................. 3-51

ADJUSTING THE TOE-IN ................................................................... 3-51

ADJUSTING THE FRONT SHOCK ABSORBER ................................ 3-53

ADJUSTING THE REAR SHOCK ABSORBER .................................. 3-54

CHECKING THE TIRE ........................................................................ 3-54

CHECKING THE WHEEL .................................................................... 3-56

CHECKING AND LUBRICATING THE CABLE ................................... 3-57

LUBRICATING THE LEVERS, PEDAL, ETC. ..................................... 3-57

ELECTRICAL .............................................................................................. 3-58

CHECKING THE BATTERY ................................................................ 3-58

CHECKING THE FUSE ....................................................................... 3-63

ADJUSTING THE HEADLIGHT BEAM ............................................... 3-65

CHANGING THE HEADLIGHT BULB ................................................. 3-65

CHAPTER 4.

ENGINE

ENGINE REMOVAL ...................................................................................... 4-1

AIR DUCTS, MUFFLER AND EXHAUST PIPE .................................... 4-1

SELECT LEVER UNIT AND COOLANT RESERVOIR ......................... 4-3

HOSES AND LEADS ............................................................................. 4-4

ENGINE MOUNTING BOLTS ............................................................... 4-5

INSTALLING THE ENGINE ................................................................... 4-7

CYLINDER HEAD COVER ........................................................................... 4-8

REMOVING THE CYLINDER HEAD COVER ..................................... 4-10

CHECKING THE CYLINDER HEAD COVER ..................................... 4-10

CHECKING THE TAPPET COVER ..................................................... 4-11

INSTALLING THE CYLINDER HEAD COVER ................................... 4-11

ROCKER ARMS ......................................................................................... 4-12

REMOVING THE ROCKER ARM ....................................................... 4-14

CHECKING THE ROCKER ARM ........................................................ 4-14

INSTALLING THE ROCKER ARM ...................................................... 4-15

CAMSHAFT AND CYLINDER HEAD .........................................................4-16

REMOVING THE CAMSHAFT AND CYLINDER HEAD ..................... 4-18

CHECKING THE CAMSHAFT ............................................................. 4-19

CHECKING THE CAMSHAFT SPROCKET ........................................ 4-19

CHECKING THE DECOMPRESSION SYSTEM ................................. 4-19

CHECKING THE TIMING CHAIN GUIDE ........................................... 4-20

CHECKING THE TIMING CHAIN TENSIONER .................................. 4-20

CHECKING THE CYLINDER HEAD ................................................... 4-20

INSTALLING THE CAMSHAFT AND CYLINDER HEAD .................... 4-21

VALVES AND VALVE SPRINGS ............................................................... 4-24

REMOVING THE VALVE AND VALVE SPRING ................................ 4-25

CHECKING THE VALVE AND VALVE SPRING ................................. 4-26

INSTALLING THE VALVE AND VALVE SPRING ............................... 4-30

CYLINDER AND PISTON ........................................................................... 4-32

REMOVING THE PISTON .................................................................. 4-33

CHECKING THE CYLINDER AND PISTON ....................................... 4-33

CHECKING THE PISTON RING .........................................................4-35

CHECKING THE PISTON PIN ............................................................ 4-36

INSTALLING THE PISTON ................................................................. 4-36

INSTALLING THE CYLINDER ............................................................ 4-37

RECOIL STARTER AND AC MAGNETO ................................................... 4-38

REMOVING THE AC MAGNETO ........................................................ 4-41

DISASSEMBLING THE RECOIL STARTER ....................................... 4-41

CHECKING THE AC MAGNETO ........................................................ 4-41

CHECKING THE STARTER CLUTCH ................................................ 4-42

CHECKING THE STARTER PULLEY ................................................. 4-43

CHECKING THE RECOIL STARTER ................................................. 4-43

ASSEMBLEING THE RECOIL STARTER .......................................... 4-43

INSTALLING THE AC MAGNETO ...................................................... 4-44

BALANCER GEARS AND OIL PUMP GEARS .......................................... 4-47

REMOVING THE BALANCER DRIVE GEAR

AND BALANCER DRIVEN GEAR ................................................... 4-48

REMOVING THE BALANCER DRIVE GEAR ..................................... 4-48

CHECKING THE OIL PUMP DRIVE ................................................... 4-48

CHECKING THE BALANCER DRIVE ................................................. 4-49

INSTALLING THE BALANCER DRIVE GEAR

AND BALANCER DRIVEN GEAR ................................................... 4-49

PRIMARY AND SECONDARY SHEAVES ................................................. 4-51

PRIMARY SHEAVE ............................................................................. 4-53

SECONDARY SHEAVE ...................................................................... 4-54

REMOVING THE PRIMARY AND SECONDARY SHEAVES ............. 4-55

DISASSEMBLING THE SECONDARY SHEAVE ................................ 4-55

CHEKING THE PRIMARY SHEAVE ................................................... 4-56

CHECKING THE SECONDARY SHEAVE .......................................... 4-56

ASSEMBLING THE PRIMARY SHEAVE ............................................ 4-57

ASSEMBLING THE SECONDARY SHEAVE ...................................... 4-57

INSTALLING THE PRIMARY AND SECONDARY SHEAVES ............ 4-59

CLUTCH ...................................................................................................... 4-60

REMOVING THE CLUTCH ................................................................. 4-62

CHECKING THE CLUTCH .................................................................. 4-62

INSTALLING THE CLUTCH ................................................................ 4-63

CRANKCASE .............................................................................................. 4-65

STARTER MOTOR, TIMING CHAIN AND OIL FILTER ...................... 4-65

CRANKCASE ...................................................................................... 4-67

CRANKCASE BEARING ..................................................................... 4-68

SEPARATING THE CRANKCASE ...................................................... 4-69

CHECKING THE TIMING CHAIN AND GUIDE ................................... 4-69

CHECKING THE OIL DELIVERY PIPE ............................................... 4-69

CHECKING THE CRANKCASE .......................................................... 4-70

CHECKING THE BEARINGS .............................................................. 4-70

ASSEMBLING THE CRANKCASE ...................................................... 4-70

INSTALLATING THE SHIFT LEVER ................................................... 4-71

CRANKSHAFT AND OIL PUMP ................................................................ 4-72

OIL PUMP ........................................................................................... 4-73

REMOVING THE CRANKSHAFT ....................................................... 4-74

CHECKING THE OIL PUMP ............................................................... 4-74

CHECKING THE RELIEF VALVE ....................................................... 4-75

CHECKING THE OIL STRAINER ....................................................... 4-75

ASSEMBLING THE OIL PUMP ........................................................... 4-75

CHECKING THE CRANKSHAFT ........................................................ 4-76

INSTALLING THE CRANKSHAFT AND BALANCER ......................... 4-77

TRANSMISSION ......................................................................................... 4-78

REMOVING THE TRANSMISSION .................................................... 4-81

CHECKING THE SHIFT FORK ........................................................... 4-81

CHECKING THE SHIFT CAM ............................................................. 4-82

CHECKING THE DRIVE AXLE ........................................................... 4-82

CHECKING THE HIGH WHEEL GEAR

AND MIDDLE DRIVE GEAR ........................................................... 4-82

CHECKING THE SECONDARY SHAFT

AND DRIVEN SPROCKET .............................................................. 4-83

CHECKING THE CHAIN ..................................................................... 4-83

CHECKING THE STOPPER LEVER

AND STOPPER WHEEL ................................................................. 4-83

ASSEMBLING THE SHIFT FORK ASSEMBLY .................................. 4-84

INSTALLING THE TRANSMISSION .................................................... 4-84

MIDDLE GEAR ........................................................................................... 4-85

MIDDLE DRIVE SHAFT ...................................................................... 4-85

MIDDLE DRIVEN SHAFT .................................................................... 4-86

REMOVING THE MIDDLE DRIVE SHAFT ......................................... 4-88

REMOVING THE MIDDLE DRIVEN SHAFT ....................................... 4-88

CHECKING THE PINION GEAR .........................................................4-91

MIDDLE DRIVE AND DRIVEN GEAR SHIM SELECTION ................. 4-91

INSTALLING THE MIDDLE DRIVEN SHAFT ..................................... 4-94

INSTALLING THE MIDDLE DRIVE SHAFT ........................................ 4-96

MEASURING THE MIDDLE GEAR BACKLASH ................................. 4-97

CHAPTER 5.

COOLING SYSTEM

RADIATOR .................................................................................................... 5-1

CHECKING THE RADIATOR ................................................................ 5-3

INSTALLING THE RADIATOR .............................................................. 5-4

THERMOSTAT .............................................................................................. 5-5

CHECKING THE THERMOSTAT .......................................................... 5-6

INSTALLING THE THERMOSTAT ........................................................ 5-6

WATER PUMP .............................................................................................. 5-7

DISASSEMBLING THE WATER PUMP ................................................ 5-9

CHECKING THE WATER PUMP .......................................................... 5-9

ASSEMBLING THE WATER PUMP .................................................... 5-10

CHAPTER 6.

CARBURETION

CARBURETOR ............................................................................................. 6-1

DISASSEMBLING THE CARBURETOR ............................................... 6-4

CHECKING THE CARBURETOR ......................................................... 6-4

ASSEMBLING THE CARBURETOR ..................................................... 6-6

ADJUSTING THE FUEL LEVEL ............................................................ 6-7

CHAPTER 7.

DRIVE TRAIN

TROUBLESHOOTING .................................................................................. 7-1

FRONT CONSTANT VELOCITY JOINTS

AND DIFFERENTIAL GEAR .................................................................... 7-4

DISASSEMBLING THE UNIVERSAL JOINT ........................................ 7-9

REMOVING THE RING GEAR ............................................................ 7-10

CHECKING THE CONSTANT VELOCITY JOINT .............................. 7-10

CHECKING THE DIFFERENTIAL GEAR ............................................ 7-10

CHECKING THE GEAR MOTOR ........................................................ 7-11

ASSEMBLING THE FRONT CONSTANT VELOCITY JOINT ............. 7-11

ASSEMBLING THE DIFFERENTIAL GEAR ....................................... 7-12

INSTALLING THE UNIVERSAL JOINT ............................................... 7-14

MEASURING AND ADJUSTING

THE DIFFERENTIAL GEAR LASH ................................................. 7-15

CHECKING THE DIFFERENTIAL GEAR OPERATION ..................... 7-17

REAR CONSTANT VELOCITY JOINT/FINAL DRIVE GEAR

AND DRIVE SHAFT ................................................................................ 7-18

ASSEMBLING THE REAR CONSTANT VELOCITY JOINT ............... 7-22

DISASSEMBLING THE FINAL DRIVE GEAR ..................................... 7-23

REMOVING AND DISASSEMBLING

THE FINAL DRIVE ROLLER BEARING .......................................... 7-24

POSITIONING THE FINAL DRIVE PINION GEAR

AND RING GEAR ............................................................................ 7-25

CHECKING THE DRIVE SHAFT .........................................................7-30

CHECKING THE FINAL DRIVE GEAR ............................................... 7-30

MEASUREMENT AND ADJUSTING THE FINAL GEAR LASH .......... 7-31

ASSEMBLING THE FINAL DRIVE GEAR ........................................... 7-33

INSTALLING THE FINAL DRIVE GEAR ............................................. 7-33

CHAPTER 8.

CHASSIS

FRONT WHEELS AND BRAKE DISCS ....................................................... 8-1

FRONT WHEELS .................................................................................. 8-1

CHECKING THE FRONT WHEEL ........................................................ 8-3

CHECKING THE FRONT WHEEL HUB ................................................ 8-3

CHECKING THE FRONT BRAKE DISC ............................................... 8-4

INSTALLING THE FRONT WHEEL HUB .............................................. 8-4

INSTALLING THE FRONT WHEEL ...................................................... 8-4

REAR WHEELS AND BRAKE DISC ............................................................ 8-6

REAR WHEELS .................................................................................... 8-6

REAR BRAKE DISC .............................................................................. 8-7

CHECKING THE REAR WHEEL ...........................................................8-8

CHECKING THE REAR WHEEL HUB .................................................. 8-8

CHECKING THE REAR BRAKE DISC .................................................. 8-8

INSTALLING THE REAR WHEEL HUB ................................................ 8-9

INSTALLING THE REAR WHEEL ......................................................... 8-9

FRONT AND REAR BRAKES .................................................................... 8-10

FRONT BRAKE PADS ........................................................................ 8-10

REAR BRAKE PADS ........................................................................... 8-11

REPLACING THE FRONT BRAKE PAD ............................................. 8-12

REPLACING THE REAR BRAKE PAD ............................................... 8-14

FRONT BRAKE MASTER CYLINDER ................................................ 8-16

REAR BRAKE MASTER CYLINDER .................................................. 8-18

CHECKING THE MASTER CYLINDER .............................................. 8-21

ASSEMBLING THE FRONT BRAKE MASTER CYLINDER ............... 8-22

ASSEMBLING THE REAR BRAKE MASTER CYLINDER .................. 8-22

INSTALLING THE FRONT BRAKE MASTER CYLINDER .................. 8-23

INSTALLING THE REAR BRAKE MASTER CYLINDER .................... 8-24

FRONT BRAKE CALIPER ................................................................... 8-26

REAR BRAKE CALIPER ..................................................................... 8-28

DISASSEMBLING THE BRAKE CALIPER ......................................... 8-30

DISASSEMBLING THE REAR BRAKE CALIPER .............................. 8-30

CHECKING THE FRONT AND REAR BRAKE CALIPER ................... 8-31

ASSEMBLING THE FRONT BRAKE CALIPER .................................. 8-32

INSTALLING THE FRONT BRAKE CALIPER ....................................8-32

ASSEMBLING THE REAR BRAKE CALIPER ....................................8-34

INSTALLING THE REAR BRAKE CALIPER ....................................... 8-35