Yamaha YFM660RN User manual

YFM660RN
YFM660RNC
SERVICE MANUAL
LIT-11616-14-21 5LP-28197-E0

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 4is provided for removal and disassembly jobs.
2. Numbers 5are 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 7accompanies 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 8are given in addition
to the exploded diagram and the job instruction chart.

EB003000
ILLUSTRATED SYMBOLS
Illustrated symbols 1to 9are printed on the
top right of each page and indicate the subject
of each chapter.
1General information
2Specifications
3Periodic checks and adjustments
4Chassis
5Engine
6Cooling system
7Carburetion
8Electrical
9Troubleshooting
Illustrated symbols 0to Gare used to identify
the specifications appearing in the text.
0Can be serviced with engine mounted
AFilling fluid
BLubricant
CSpecial tool
DTorque
EWear limit, clearance
FEngine speed
GΩ, V, A
Illustrated symbols Hto Nin the exploded
diagrams indicate the types of lubricants and
lubrication points.
HApply engine oil
IApply gear oil
JApply molybdenum disulfide oil
KApply wheel bearing grease
LApply lightweight lithium soap base grease
MApply molybdenum disulfide grease
NApply silicon grease
Illustrated symbols Oto Pin the exploded
diagrams indicate where to apply a locking
agent Oand when to install a new part P.
OApply the locking agent (LOCTITE)
PReplace
12
34
56
78
90
AB
CD
EFG
HIJ
K
OP
GEN
INFO SPEC
CHK
ADJ
CHAS
ENG
COOL
CARB
–+
ELEC
TRBL
SHTG
T
R
.
.
EGM
BLS MS
LMN
LT New

TABLE OF CONTENTS
GENERAL INFORMATION GEN
INFO 1
SPECIFICATIONS SPEC 2
PERIODIC CHECKS AND
ADJUSTMENTS CHK
ADJ 3
CHASSIS CHAS 4
ENGINE ENG 5
COOLING SYSTEM COOL 6
CARBURETION CARB 7
ELECTRICAL ELEC 8
TROUBLESHOOTING TRBL
SHTG 9
–+

CHAPTER 1.
GENERAL INFORMATION
MACHINE IDENTIFICATION ........................................................................1-1
VEHICLE IDENTIFICATION NUMBER .................................................1-1
MODEL LABEL ......................................................................................1-1
IMPORTANT INFORMATION .......................................................................1-2
PREPARATION FOR REMOVAL PROCEDURES ...............................1-2
REPLACEMENT PARTS .......................................................................1-2
GASKETS, OIL SEALS AND O-RINGS ................................................1-2
LOCK WASHERS/PLATES AND COTTER PINS .................................1-3
BEARINGS AND OIL SEALS ................................................................1-3
CIRCLIPS ..............................................................................................1-3
CHECKING OF CONNECTIONS ..................................................................1-4
SPECIAL TOOLS ..........................................................................................1-5
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 ..............................................................................2-23
CABLE ROUTING .......................................................................................2-27

GEN
INFO 1
SPEC 2
CHK
ADJ 3
CHAS 4
ENG 5
COOL 6
CARB 7
ELEC 8
TRBL
SHTG 9
–+
CHAPTER 3.
PERIODIC CHECKS AND ADJUSTMENTS
INTRODUCTION ...........................................................................................3-1
PERIODIC MAINTENANCE/LUBRICATION INTERVALS ..........................3-1
SEAT, FENDERS AND FUEL TANK ............................................................3-3
SEAT, FRONT PANEL, FOOTREST GUARDS
AND ENGINE SKID PLATE ...............................................................3-3
HEADLIGHTS AND FRONT FENDER ..................................................3-4
REAR FENDER .....................................................................................3-5
FUEL TANK ...........................................................................................3-6
ENGINE .........................................................................................................3-8
ADJUSTING THE VALVE CLEARANCE ..............................................3-8
ADJUSTING THE TIMING CHAIN ......................................................3-11
ADJUSTING THE IDLING SPEED ......................................................3-11
ADJUSTING THE THROTTLE LEVER FREE PLAY ..........................3-12
ADJUSTING THE SPEED LIMITER ....................................................3-14
ADJUSTING THE STARTER CABLE .................................................3-15
CHECKING THE SPARK PLUG .........................................................3-16
CHECKING THE IGNITION TIMING ...................................................3-17
MEASURING THE COMPRESSION PRESSURE ..............................3-18
CHECKING THE ENGINE OIL LEVEL ................................................3-19
CHANGING THE ENGINE OIL ...........................................................3-20
ADJUSTING THE CLUTCH CABLE ....................................................3-23
CLEANING THE AIR FILTER ..............................................................3-24
CHECKING THE COOLANT LEVEL ...................................................3-27
CHANGING THE COOLANT ...............................................................3-27
CHECKING THE COOLANT TEMPERATURE WARNING LIGHT .....3-31
CLEANING THE SPARK ARRESTER ................................................3-31
CHASSIS ....................................................................................................3-33
ADJUSTING THE FRONT BRAKE .....................................................3-33
ADJUSTING THE REAR BRAKE ........................................................3-33
ADJUSTING THE PARKING BRAKE ..................................................3-34
CHECKING THE BRAKE FLUID LEVEL .............................................3-35
CHECKING THE FRONT BRAKE PAD ..............................................3-36
CHECKING THE REAR BRAKE PAD .................................................3-36
ADJUSTING THE REAR BRAKE LIGHT SWITCH .............................3-36
CHECKING THE BRAKE HOSE .........................................................3-37
BLEEDING THE HYDRAULIC BRAKE SYSTEM ...............................3-38
ADJUSTING THE SHIFT PEDAL ........................................................3-39
ADJUSTING THE REVERSE CONTROL CABLE ..............................3-40
ADJUSTING THE DRIVE CHAIN SLACK ...........................................3-40
CHECKING THE STEERING SYSTEM ..............................................3-42
ADJUSTING THE TOE-IN ...................................................................3-42
ADJUSTING THE FRONT SHOCK ABSORBER ................................3-44
ADJUSTING THE REAR SHOCK ABSORBER ..................................3-45

CHECKING THE TIRE ........................................................................3-47
CHECKING THE WHEEL ....................................................................3-49
CHECKING AND LUBRICATING THE CABLE ...................................3-49
LUBRICATING THE LEVERS AND PEDAL ........................................3-50
ELECTRICAL ..............................................................................................3-51
CHECKING THE BATTERY ................................................................3-51
CHECKING THE FUSE .......................................................................3-56
ADJUSTING THE HEADLIGHT BEAM ...............................................3-58
REPLACING THE HEADLIGHT BULB ................................................3-58
CHAPTER 4.
CHASSIS
FRONT WHEELS ..........................................................................................4-1
FRONT WHEELS ..................................................................................4-1
CHECKING THE WHEEL ......................................................................4-3
CHECKING THE WHEEL HUB .............................................................4-3
CHECKING THE BRAKE DISC .............................................................4-4
INSTALLING WHEEL HUB ...................................................................4-5
INSTALLING THE WHEEL ....................................................................4-5
REAR WHEELS, WHEEL AXLE AND HUB .................................................4-6
REAR WHEELS ....................................................................................4-6
WHEEL AXLE AND HUB ......................................................................4-7
REMOVING THE REAR AXLE ..............................................................4-9
CHECKING THE WHEEL ....................................................................4-10
CHECKING THE WHEEL HUB ...........................................................4-10
CHECKING THE REAR AXLE ............................................................4-10
CHECKING THE HUB .........................................................................4-11
CHECKING THE BRAKE DISC ...........................................................4-11
INSTALLING THE NUTS (REAR AXLE) .............................................4-11
INSTALLING THE WHEEL HUB .........................................................4-12
INSTALLING THE WHEEL ..................................................................4-12
FRONT AND REAR BRAKES ....................................................................4-13
FRONT BRAKE PADS ........................................................................4-13
REAR BRAKE PADS ...........................................................................4-14
REPLACING THE FRONT BRAKE PAD .............................................4-15
REPLACING THE REAR BRAKE PAD ...............................................4-17
FRONT BRAKE MASTER CYLINDER ................................................4-19
REAR BRAKE MASTER CYLINDER ..................................................4-21
CHECKING THE MASTER CYLINDER ..............................................4-24
ASSEMBLING THE FRONT
AND REAR BRAKE MASTER CYLINDER ......................................4-25
INSTALLING THE FRONT BRAKE MASTER CYLINDER ..................4-25
INSTALLING THE REAR BRAKE MASTER CYLINDER ....................4-27
FRONT BRAKE CALIPERS ................................................................4-29
REAR BRAKE CALIPER .....................................................................4-31
DISASSEMBLING THE FRONT AND REAR BRAKE CALIPER ........4-34

GEN
INFO 1
SPEC 2
CHK
ADJ 3
CHAS 4
ENG 5
COOL 6
CARB 7
ELEC 8
TRBL
SHTG 9
–+
CHECKING THE FRONT AND REAR BRAKE CALIPER ...................4-34
ASSEMBLING THE FRONT BRAKE CALIPER ..................................4-35
ASSEMBLING THE REAR BRAKE CALIPER ....................................4-36
INSTALLING THE FRONT BRAKE CALIPER ....................................4-37
INSTALLING THE REAR BRAKE CALIPER .......................................4-38
STEERING SYSTEM ..................................................................................4-40
HANDLEBAR .......................................................................................4-40
REMOVING THE FRONT BRAKE SWITCH, PARK SWITCH
AND CLUTCH SWITCH ..................................................................4-42
REMOVING THE HANDLEBAR GRIP ................................................4-42
CHECKING THE HANDLEBAR ..........................................................4-42
INSTALLING THE HANDLEBAR ........................................................4-43
INSTALLING THE HANDLEBAR GRIP ...............................................4-43
INSTALLING THE CLUTCH LEVER ...................................................4-43
INSTALLING THE BRAKE MASTER CYLINDER ...............................4-44
STEERING STEM ...............................................................................4-45
REMOVING THE BEARING RETAINER ............................................4-47
CHECKING THE STEERING STEM ...................................................4-47
INSTALLING THE BEARING RETAINER ...........................................4-47
INSTALLING THE LOCK WASHER ....................................................4-47
TIE-ROD AND STEERING KNUCKLE ................................................4-48
REMOVING THE STEERING KNUCKLE ...........................................4-49
CHECKING THE TIE-ROD ..................................................................4-49
CHECKING THE STEERING KNUCKLE ............................................4-49
INSTALLING THE TIE-ROD ................................................................4-49
FRONT ARMS AND FRONT SHOCK ABSORBERS ................................4-50
REMOVING THE FRONT ARM ..........................................................4-52
CHECKING THE FRONT ARM ...........................................................4-52
CHECKING THE FRONT SHOCK ABSORBER .................................4-52
CHECKING THE BALL JOINT ............................................................4-53
INSTALLING THE FRONT ARM .........................................................4-54
REAR SHOCK ABSORBER AND RELAY ARM ........................................4-55
HANDLING THE REAR SHOCK ABSORBER
AND GAS CYLINDER .....................................................................4-57
DISPOSING OF A REAR SHOCK ABSORBER
AND GAS CYLINDER .....................................................................4-57
REMOVING THE REAR SHOCK ABSORBER ...................................4-58
CHECKING THE REAR SHOCK ABSORBER ....................................4-58
CHECKING THE RELAY ARM AND CONNECTING ARM .................4-58
INSTALLING THE RELAY ARM AND CONNECTING ARM ...............4-59
INSTALLING THE REAR SHOCK ABSORBER ..................................4-59
SWINGARM AND DRIVE CHAIN ...............................................................4-60
REMOVING THE SWINGARM ............................................................4-62
CHECKING THE SWINGARM ............................................................4-62
CHECKING THE DRIVE CHAIN .........................................................4-63
INSTALLING THE SWINGARM ..........................................................4-65
INSTALLING THE DRIVE SPROCKET ...............................................4-65

CHAPTER 5.
ENGINE
ENGINE REMOVAL ......................................................................................5-1
MUFFLER AND EXHAUST PIPES .......................................................5-1
LEFT FOOTREST .................................................................................5-2
LEADS, CABLES AND HOSES ............................................................5-3
ENGINE MOUNTING BOLTS ...............................................................5-5
INSTALLING THE ENGINE ...................................................................5-7
CYLINDER HEAD COVER ...........................................................................5-8
REMOVING THE CYLINDER HEAD COVER .....................................5-10
CHECKING THE CYLINDER HEAD COVER .....................................5-10
CHECKING THE TAPPET COVER .....................................................5-11
INSTALLING THE CYLINDER HEAD COVER ...................................5-11
ROCKER ARMS .........................................................................................5-12
REMOVING THE ROCKER ARM .......................................................5-14
CHECKING THE ROCKER ARM ........................................................5-14
INSTALLING THE ROCKER ARM ......................................................5-15
CAMSHAFT AND CYLINDER HEAD .........................................................5-16
REMOVING THE CAMSHAFT AND CYLINDER HEAD .....................5-18
CHECKING THE CAMSHAFT .............................................................5-19
CHECKING THE CAMSHAFT SPROCKET ........................................5-19
CHECKING THE DECOMPRESSION SYSTEM .................................5-19
CHECKING THE TIMING CHAIN GUIDE ...........................................5-20
CHECKING THE TIMING CHAIN TENSIONER ..................................5-20
CHECKING THE CYLINDER HEAD ...................................................5-20
INSTALLING THE CAMSHAFT AND CYLINDER HEAD ....................5-21
VALVES AND VALVE SPRINGS ...............................................................5-24
REMOVING THE VALVE AND VALVE SPRING ................................5-25
CHECKING THE VALVE AND VALVE SPRING .................................5-26
INSTALLING THE VALVE AND VALVE SPRING ...............................5-30
CYLINDER AND PISTON ...........................................................................5-32
REMOVING THE PISTON ..................................................................5-33
CHECKING THE CYLINDER AND PISTON .......................................5-33
CHECKING THE PISTON RING .........................................................5-35
CHECKING THE PISTON PIN INSPECTION .....................................5-36
INSTALLING THE PISTON .................................................................5-36
INSTALLING THE CYLINDER ............................................................5-37
AC MAGNETO ............................................................................................5-38
REMOVING THE AC MAGNETO ROTOR ..........................................5-40
CHECKING THE COIL ........................................................................5-40
CHECKING THE STARTER CLUTCH ................................................5-41
INSTALLING THE AC MAGNETO ROTOR ........................................5-42

GEN
INFO 1
SPEC 2
CHK
ADJ 3
CHAS 4
ENG 5
COOL 6
CARB 7
ELEC 8
TRBL
SHTG 9
–+
CLUTCH ......................................................................................................5-43
REMOVING THE CLUTCH .................................................................5-47
REMOVING THE PRIMARY DRIVE GEAR
AND BALANCER DRIVEN GEAR ...................................................5-47
CHECKING THE FRICTION PLATE ...................................................5-48
CHECKING THE CLUTCH PLATE .....................................................5-48
CHECKING THE CLUTCH SPRING ...................................................5-49
CHECKING THE CLUTCH HOUSING ................................................5-49
CHECKING THE CLUTCH BOSS .......................................................5-49
CHECKING THE PRESSURE PLATE ................................................5-49
CHECKING THE PULL LEVER SHAFT AND PULL ROD ..................5-50
CHECKING THE PRIMARY DRIVE ....................................................5-50
CHECKING THE BALANCER DRIVE .................................................5-50
INSTALLING THE PRIMARY DRIVE GEAR
AND BALANCER DRIVEN GEAR ...................................................5-51
INSTALLING THE CLUTCH ................................................................5-52
OIL PUMP ...................................................................................................5-54
CHECKING THE OIL PUMP ...............................................................5-56
ASSEMBLING THE OIL PUMP............................................................5-56
SHIFT SHAFT .............................................................................................5-57
CHECKING THE SHIFT SHAFT .........................................................5-59
CHECKING THE STOPPER LEVER ..................................................5-59
CHECKING THE SHIFT GUIDE AND SHIFT LEVER .........................5-59
CHECKING THE SEGMENT ...............................................................5-59
INSTALLING THE SHIFT LEVER .......................................................5-59
INSTALLING THE STOPPER LEVER ................................................5-60
INSTALLING THE SHIFT SHAFT .......................................................5-61
CRANKCASE ..............................................................................................5-62
TIMING CHAIN AND SPEED SENSOR ROTOR ................................5-62
CRANKCASE ......................................................................................5-64
CRANKCASE BEARING .....................................................................5-65
SEPARATING THE CRANKCASE.......................................................5-66
CHECKING THE TIMING CHAIN AND GUIDE ...................................5-66
CHECKING THE OIL STRAINER .......................................................5-66
CHECKING THE CRANKCASE ..........................................................5-67
CHECKING THE BEARINGS ..............................................................5-67
ASSEMBLING THE CRANKCASE ......................................................5-67
CRANKSHAFT AND BALANCER ..............................................................5-69
REMOVING THE CRANKSHAFT .......................................................5-70
CHECKING THE CRANKSHAFT ........................................................5-70
INSTALLING THE CRANKSHAFT ......................................................5-71

TRANSMISSION .........................................................................................5-72
MAIN AXLE .........................................................................................5-74
DRIVE AXLE .......................................................................................5-75
CHECKING THE SHIFT FORK ...........................................................5-77
CHECKING THE SHIFT DRUM ..........................................................5-77
CHECKING THE TRANSMISSION .....................................................5-77
ASSEMBLING THE MAIN AXLE AND DRIVE AXLE ..........................5-78
INSTALLING THE TRANSMISSION ...................................................5-79
CHAPTER 6.
COOLING SYSTEM
RADIATOR ....................................................................................................6-1
CHECKING THE RADIATOR ................................................................6-3
INSTALLING THE RADIATOR ..............................................................6-4
THERMOSTAT ..............................................................................................6-5
CHECKING THE THERMOSTAT ..........................................................6-7
ASSEMBLING THE THERMOSTAT .....................................................6-7
WATER PUMP ..............................................................................................6-8
DISASSEMBLING THE WATER PUMP ..............................................6-11
CHECKING THE WATER PUMP ........................................................6-11
ASSEMBLING THE WATER PUMP ....................................................6-12
CHAPTER 7.
CARBURETION
CARBURETORS ...........................................................................................7-1
DISASSEMBLING THE CARBURETOR ...............................................7-5
CHECKING THE CARBURETOR .........................................................7-5
ASSEMBLING THE CARBURETOR .....................................................7-7
ADJUSTING THE FUEL LEVEL ............................................................7-8

GEN
INFO 1
SPEC 2
CHK
ADJ 3
CHAS 4
ENG 5
COOL 6
CARB 7
ELEC 8
TRBL
SHTG 9
–+
CHAPTER 8.
ELECTRICAL
ELECTRICAL COMPONENTS .....................................................................8-1
CHECKING THE SWITCH ............................................................................8-2
CHECKING THE SWITCH ....................................................................8-2
CHECKING A SWITCH SHOWN IN THE MANUAL .............................8-2
CHECKING THE SWITCH CONTINUITY .............................................8-3
IGNITION SYSTEM .......................................................................................8-5
CIRCUIT DIAGRAM ..............................................................................8-5
TROUBLESHOOTING ..........................................................................8-6
ELECTRIC STARTING SYSTEM ...............................................................8-11
CIRCUIT DIAGRAM ............................................................................8-11
STARTING CIRCUIT OPERATION .....................................................8-12
TROUBLESHOOTING ........................................................................8-13
STARTER MOTOR .............................................................................8-16
CHECKING THE STARTER MOTOR .................................................8-17
ASSEMBLING THE STARTER MOTOR .............................................8-18
CHARGING SYSTEM .................................................................................8-19
CIRCUIT DIAGRAM ............................................................................8-19
TROUBLESHOOTING ........................................................................8-20
LIGHTING SYSTEM ....................................................................................8-22
CIRCUIT DIAGRAM ............................................................................8-22
TROUBLESHOOTING ........................................................................8-23
CHECKING THE LIGHTING SYSTEM ................................................8-25
SIGNAL SYSTEM .......................................................................................8-27
CIRCUIT DIAGRAM ............................................................................8-27
TROUBLESHOOTING ........................................................................8-28
CHECKING THE SIGNAL SYSTEM ...................................................8-30
COOLING SYSTEM ....................................................................................8-36
CIRCUIT DIAGRAM ............................................................................8-36
TROUBLESHOOTING .......................................................................8-37

CHAPTER 9.
TROUBLESHOOTING
STARTING FAILURE/HARD STARTING .....................................................9-1
FUEL SYSTEM ......................................................................................9-1
ELECTRICAL SYSTEM .........................................................................9-1
COMPRESSION SYSTEM ....................................................................9-2
POOR IDLE SPEED PERFORMANCE ........................................................9-2
POOR IDLE SPEED PERFORMANCE .................................................9-2
POOR MEDIUM AND HIGH-SPEED PERFORMANCE ...............................9-2
POOR MEDIUM AND HIGH-SPEED PERFORMANCE .......................9-2
FAULTY GEAR SHIFTING ...........................................................................9-3
HARD SHIFTING ...................................................................................9-3
SHIFT PEDAL DOES NOT MOVE ........................................................9-3
JUMP-OUT GEAR .................................................................................9-3
CLUTCH SLIPPING/DRAGGING .................................................................9-3
CLUTCH SLIPPING ..............................................................................9-3
CLUTCH DRAGGING ...........................................................................9-3
OVERHEATING ............................................................................................9-4
OVERHEATING ....................................................................................9-4
OVER COOLING ...........................................................................................9-4
COOLING SYSTEM ..............................................................................9-4
FAULTY BRAKE ...........................................................................................9-4
POOR BRAKING EFFECT ....................................................................9-4
SHOCK ABSORBER MALFUNCTION .........................................................9-5
MALFUNCTION .....................................................................................9-5
UNSTABLE HANDLING ...............................................................................9-5
UNSTABLE HANDLING ........................................................................9-5
LIGHTING SYSTEM ......................................................................................9-5
HEADLIGHT DARK ...............................................................................9-5
BULB BURNT OUT ...............................................................................9-5

1 - 1
GEN
INFO
MACHINE IDENTIFICATION
GENERAL INFORMATION
MACHINE IDENTIFICATION
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1is
stamped into the left side of the frame.
MODEL LABEL
The model label 1is affixed to the air filter
case cover. This information will be needed to
order spare parts.

1 - 2
GEN
INFO
EB101000
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL
PROCEDURES
1.Remove all dirt, mud, dust and foreign mate-
rial before removal and disassembly.
2.Use proper tools and cleaning equipment.
Refer to the “SPECIAL TOOLS” section.
3.When disassembling the machine, always
keep mated parts together. This includes
gears, cylinder, piston and other parts that
have been “mated” through normal wear.
Mated parts must always be reused or
replaced as an assembly.
4.During machine disassembly, clean all parts
and place them in trays in the order of disas-
sembly. This will speed up assembly and
allow for the correct installation of all parts.
5.Keep all parts away from any source of fire.
EB101010
REPLACEMENT PARTS
1.Use only genuine Yamaha parts for all
replacements. Use oil and grease recom-
mended 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.
IMPORTANT INFORMATION

1 - 3
GEN
INFO
EB101030
LOCK WASHERS/PLATES AND COTTER
PINS
1.Replace all lock washers/plates 1and 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
1.Install bearings and oil seals so that the
manufacturer’s marks or numbers are visible.
When installing oil seals, apply a light coat-
ing of lightweight lithium base grease to the
seal lips. Oil bearings liberally when install-
ing, if appropriate.
1Oil seal
CAUTION:
Do not use compressed air to spin the
bearings dry. This will damage the bearing
surfaces.
1Bearing
EB101050
CIRCLIPS
1.Check all circlips carefully before reassem-
bly. Always replace piston pin clips after one
use. Replace distorted circlips. When install-
ing a circlip 1, make sure that the sharp-
edged corner 2is positioned opposite the
thrust 3it receives. See sectional view.
4Shaft
IMPORTANT INFORMATION

1 - 4
GEN
INFO
CHECKING OF CONNECTIONS
EB801000
CHECKING OF CONNECTIONS
Check the connectors for stains, rust, mois-
ture, etc.
1.Disconnect:
●Connector
2.Check:
●Connector
Moisture →Dry each terminal with an air
blower.
Stains/rust →Connect and disconnect the
terminals several times.
3.Check:
●Connector leads
Looseness →Bend up the pin 1and con-
nect the terminals.
4.Connect:
●Connector terminals
NOTE:
The two terminals “click” together.
5.Check:
●Continuity (using a pocket tester)
NOTE:
●If there is no continuity, clean the terminals.
●When checking the wire harness be sure to
perform steps 1 to 3.
●As a quick remedy, use a contact revitalizer
available at most part stores.
●Check the connector with a pocket tester as
shown.

1 - 5
GEN
INFO
SPECIAL TOOLS
EB102001
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. Special tools may differ by shape and part number from country to
country. In such a case, two types are provided.
When placing an order, refer to the list provided below to avoid any mistakes.
For US and CDN
P/N. YM-, YU-, YS-, YK-, ACC-
Except for US and CDN
P/N. 90890-
Tool No. Tool name/How to use Illustration
Bolt
90890-01083
Weight
90890-01084
Set
YU-01083-A
Slide hammer bolt (M6)/weight/set
These tools are used to remove the rocker
arm shaft.
90890-01135
YU-01135-A
Crankcase separating tool
This tool is used to separate the crank-
case.
Pot
90890-01274
Bolt
90890-01275
Crankshaft installer pot
Crankshaft installer bolt
These tools are used to install the crank-
shaft.
YU-90050
Crankshaft installer set
These tools are used to install the crank-
shaft.
Adapter
90890-04059
YM-90069
Spacer
90890-04081
YM-91044
Adapter
Spacer (crankshaft installer)
These tools are used to install the crank-
shaft.
90890-01016
Spacer
This tool is used to install the crankshaft.

1 - 6
GEN
INFO
SPECIAL TOOLS
90890-01304
YU-01304
Piston pin puller
This tool is used to remove the piston pin.
90890-01311
YM-08035
Tappet adjusting tool (3 mm)
This tool is necessary for adjusting the
valve clearance.
90890-01312
YM-01312-A
Fuel level gauge
This gauge is used to measure the fuel
level in the float chamber.
90890-01325
YU-24460-01
Radiator cap tester
This tool is used to check the cooling sys-
tem.
90890-01352
YU-33984
Adapter
This tool is used to check the cooling sys-
tem.
90890-01327
YM-01327
Damper rod holder (30 mm)
This tool is needed to loosen and tighten
the steering stem bearing retainer.
90890-01362
YU-33270
Flywheel puller
These tools are needed to remove the
rotor.
90890-01419
YM-37132
Axle nut wrench (50 mm)
This tool is needed to loosen or tighten the
rear axle nut.
Tool No. Tool name/How to use Illustration