Yamaha YZ450FA user guide

q Read this manual carefully before operating this vehicle.

2011

LIT-11626-24-22

OWNER’S SERVICE MANUAL

YZ450FA

33D-28199-11

Q

Read this manual carefully before operating this vehicle. This manual should stay with this vehicle if it is sold.

YZ450FA

OWNER'S SERVICE MANUAL

©2010 by Yamaha Motor Corporation, U.S.A.

1st Edition, May 2010

All rights reserved.

Any reprinting or unauthorized use

without the written permission of

Yamaha Motor Corporation, U.S.A.

is expressly prohibited.

Printed in Japan

P/N. LIT-11626-24-22

INTRODUCTION

Congratulations on your purchase of a Yamaha
YZ series. This model is the culmination of Ya­maha's vast experience in the production of
pacesetting racing machines. It represents the
highest grade of craftsmanship and reliability
that have made Yamaha a leader.
This manual explains operation, inspection, ba­sic maintenance and tuning of your machine. If
you have any questions about this manual or
your machine, please contact your Yamaha
dealer.

Yamaha continually seeks advancements in
product design and quality. Therefore, while
this manual contains the most current product
information available at the time of printing,
there may be minor discrepancies between
your machine and this manual. If you have any
questions concerning this manual, please con­sult your Yamaha dealer.

IMPORTANT MANUAL
INFORMATION

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

This is the safety alert symbol. It is used to
alert you to potential personal injury haz­ards. Obey all safety messages that follow
this symbol to avoid possible injury or
death.

A WARNING indicates a hazardous situa­tion which, if not avoided, could result in
death or serious injury.

A NOTICE indicates special precautions
that must be taken to avoid damage to the
vehicle or other property.

PLEASE READ THIS MANUAL CAREFULLY
AND COMPLETELY BEFORE OPERATING
THIS MACHINE. DO NOT ATTEMPT TO OP­ERATE THIS MACHINE UNTIL YOU HAVE
ATTAINED A SATISFACTORY KNOWL­EDGE OF ITS CONTROLS AND OPERATING
FEATURES AND UNTIL YOU HAVE BEEN
TRAINED IN SAFE AND PROPER RIDING
TECHNIQUES. REGULAR INSPECTIONS
AND CAREFUL MAINTENANCE, ALONG
WITH GOOD RIDING SKILLS, WILL ENSURE
THAT YOU SAFETY ENJOY THE CAPABILI­TIES AND THE RELIABILITY OF THIS MA­CHINE.

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

SAFETY INFORMATION

THIS MACHINE IS DESIGNED STRICTLY
FOR COMPETITION USE, ONLY ON A
CLOSED COURSE. It is illegal for this machine
to be operated on any public street, road, or
highway. Off-road use on public lands may also
be illegal. Please check local regulations be­fore riding.

• THIS MACHINE IS TO BE OPERATED BY
AN EXPERIENCED RIDER ONLY.
Do not attempt to operate this machine at
maximum power until you are totally familiar
with its characteristics.

• THIS MACHINE IS DESIGNED TO BE RID­DEN BY THE OPERATOR ONLY.
Do not carry passengers on this machine.

• ALWAYS WEAR PROTECTIVE APPAREL.
When operating this machine, always wear an
approved helmet with goggles or a face
shield. Also wear heavy boots, gloves, and
protective clothing. Always wear proper fitting
clothing that will not be caught in any of the
moving parts or controls of the machine.

• ALWAYS MAINTAIN YOUR MACHINE IN
PROPER WORKING ORDER.
For safety and reliability, the machine must be
properly maintained. Always perform the pre­operation checks indicated in this manual.
Correcting a mechanical problem before you
ride may prevent an accident.

• GASOLINE IS HIGHLY FLAMMABLE.
Always turn off the engine while refueling.
Take care to not spill any gasoline on the en­gine or exhaust system. Never refuel in the vi­cinity of an open flame, or while smoking.

• GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline, inhale
excess gasoline vapors, or allow any gasoline
to get into your eyes, contact a doctor imme­diately. If any gasoline spills onto your skin or
clothing, immediately wash skin areas with
soap and water, and change your clothes.

• ONLY OPERATE THE MACHINE IN AN
AREA WITH ADEQUATE VENTILATION.
Never start the engine or let it run for any
length of time in an enclosed area. Exhaust
fumes are poisonous. These fumes contain
carbon monoxide, which by itself is odorless
and colorless. Carbon monoxide is a danger­ous gas which can cause unconsciousness or
can be lethal.

• PARK THE MACHINE CAREFULLY; TURN
OFF THE ENGINE.
Always turn off the engine if you are going to
leave the machine. Do not park the machine
on a slope or soft ground as it may fall over.

• THE ENGINE, EXHAUST PIPE, MUFFLER,
AND OIL TANK WILL BE VERY HOT AFTER
THE ENGINE HAS BEEN RUN.
Be careful not to touch them or to allow any
clothing item to contact them during inspec­tion or repair.

• PROPERLY SECURE THE MACHINE BE­FORE TRANSPORTING IT.
For safety, drain the gasoline from the fuel
tank before transporting the vehicle.

YAMAHA MOTOR CORPORATION, U.S.A.

YZ MOTORCYCLE LIMITED WARRANTY

HOW TO USE THIS MANUAL

FINDING THE REQUIRED PAGE

1. This manual consists of eight chapters; "General Information", "Specifications", "Regular inspec­tion and adjustments", "Engine", "Chassis", "Fuel system", "Electrical" and "Tuning".

2. The table of contents is at the beginning of the manual. Look over the general layout of the book
before finding then required chapter and item.
Bend the book at its edge, as shown, to find the required fore edge symbol mark and go to a page
for required item and description.

MANUAL FORMAT

All of the procedures in this manual are organized in a sequential, step-by-step format. The informa­tion has been complied to provide the mechanic with an easy to read, handy reference that contains
comprehensive explanations of all disassembly, repair, assembly, and inspection operations.
In this revised format, the condition of a faulty component will precede an arrow symbol and the
course of action required will follow the symbol, e.g.,

• Bearings

Pitting/damage → Replace.

HOW TO READ DESCRIPTIONS

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 "1" is provided for removal and disassembly jobs.

2. Numbers "2" 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
"3". The meanings of the symbol marks are given on the next page.

4. A job instruction chart "4" 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 "5" are given in addition
to the exploded diagram and job instruction chart.

ILLUSTRATED SYMBOLS (Refer
to the illustration)

Illustrated symbols "1" to "7" are used to identi­fy the specifications appearing in the text.

1. With engine mounted

2. Filling fluid

3. Lubricant

4. Special tool

5. Tightening

6. Specified value, Service limit

7. Resistance (Ω), Voltage (V), Electric cur-

rent (A)
Illustrated symbols "8" to "13" in the exploded
diagrams indicate grade of lubricant and loca­tion of lubrication point.

8. Apply engine oil

9. Apply molybdenum disulfide oil

10. Apply brake fluid

11. Apply lightweight lithium-soap base grease

12. Apply molybdenum disulfide grease

13. Apply silicone grease
Illustrated symbols "14" to "15" in the exploded
diagrams indicate where to apply a locking
agent and where to install new parts.

14. Apply locking agent (LOCTITE

15. Use new one

®

)

MEMO

TABLE OF CONTENTS

GENERAL INFORMATION

SPECIFICATIONS

REGULAR INSPECTION AND
ADJUSTMENTS

ENGINE

CHASSIS

1

2

3

4

5

FUEL SYSTEM

ELECTRICAL

TUNING

6

7

8

CONTENTS

CHAPTER 1

GENERAL INFORMATION

LOCATION OF IMPORTANT LABELS ..... 1-1

DESCRIPTION ........................................... 1-2

CONSUMER INFORMATION .................... 1-3

FEATURES ................................................ 1-4

INCLUDED PARTS.................................... 1-6

IMPORTANT INFORMATION.................... 1-8

HANDLING THE ELECTRONIC

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

CHECKING OF CONNECTION ............... 1-10

SPECIAL TOOLS..................................... 1-12

CONTROL FUNCTIONS.......................... 1-17

STARTING AND BREAK-IN.................... 1-19

TORQUE-CHECK POINTS...................... 1-21

CLEANING AND STORAGE ................... 1-22

CHAPTER 2

SPECIFICATIONS

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

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

TIGHTENING TORQUES......................... 2-13

LUBRICATION DIAGRAMS .................... 2-21

CABLE ROUTING DIAGRAM.................. 2-23

CHAPTER 3

REGULAR INSPECTION AND

ADJUSTMENTS

MAINTENANCE INTERVALS.................... 3-1

PRE-OPERATION INSPECTION AND

MAINTENANCE ......................................... 3-6

ENGINE...................................................... 3-7

CHASSIS.................................................. 3-20

ELECTRICAL........................................... 3-37

TROUBLESHOOTING ............................. 3-39

CHAPTER 4

ENGINE

SEAT AND SIDE COVERS........................ 4-1

EXHAUST PIPE AND SILENCER ............. 4-3

RADIATOR................................................. 4-8

CAMSHAFTS ........................................... 4-12

CYLINDER HEAD .................................... 4-19

VALVES AND VALVE SPRINGS ............ 4-23

CYLINDER AND PISTON ........................ 4-30

CLUTCH................................................... 4-35

OIL FILTER ELEMENT AND

WATER PUMP ......................................... 4-41

BALANCER ............................................. 4-47

OIL PUMP ................................................ 4-51

KICK SHAFT AND SHIFT SHAFT........... 4-55

AC MAGNETO ......................................... 4-62

ENGINE REMOVAL................................. 4-65

CRANKCASE AND CRANKSHAFT........ 4-71

TRANSMISSION, SHIFT CAM AND

SHIFT FORK ............................................ 4-79

CHAPTER 5

CHASSIS

FRONT WHEEL AND REAR WHEEL ....... 5-2

FRONT BRAKE AND REAR BRAKE........ 5-9

FRONT FORK .......................................... 5-23

HANDLEBAR........................................... 5-36

STEERING ............................................... 5-42

SWINGARM ............................................. 5-47

REAR SHOCK ABSORBER.................... 5-54

CHAPTER 6

FUEL SYSTEM

FUEL TANK ............................................... 6-2

THROTTLE BODY ..................................... 6-6

CHAPTER 7

ELECTRICAL

ELECTRICAL COMPONENTS AND

WIRING DIAGRAM .................................... 7-1

IGNITION SYSTEM.................................... 7-4

THROTTLE POSITION

SENSOR SYSTEM..................................... 7-8

FUEL INJECTION SYSTEM .................... 7-11

FUEL PUMP SYSTEM ............................. 7-44

ELECTRICAL COMPONENTS ................ 7-45

CHAPTER 8

TUNING

CHASSIS.................................................... 8-1

LOCATION OF IMPORTANT LABELS

GENERAL INFORMATION

LOCATION OF IMPORTANT LABELS

Please read the following important labels carefully before operating this vehicle.

1

Premium unleaded
gasoline only.

3FB-2415E-02

WARNING

This unit contains high pressure nitrogen gas.
Mishandling can cause explosion.
Read owner’s manual for instructions.
Do not incinerate, puncture or open.

4AA-22259-80

For use only on a closed course
in sanctioned competition.

This motorcycle does not meet
EPA noise and emissions
standards and is not for general
off-road recreational riding.

17D-2812P-00

1-1

DESCRIPTION

DESCRIPTION

1. Clutch lever

2. Front brake lever

3. Throttle grip

4. Radiator cap

5. Fuel tank cap

6. Engine stop switch

7. Kickstarter crank

8. Fuel tank

9. Radiator

• The machine you have purchased may differ slightly from those shown in the following.

• Designs and specifications are subject to change without notice.

10. Coolant drain bolt

11. Rear brake pedal

12. Valve joint

13. Air cleaner

14. Drive chain

15. Shift pedal

16. Oil level check window

17. Starter knob/idle screw

18. Front fork

1-2

CONSUMER INFORMATION

There are two significant reasons for knowing
the serial number of your machine:

1. When ordering parts, you can give the num­ber to your Yamaha dealer for positive iden­tification of the model you own.

2. If your machine is stolen, the authorities will
need the number to search for and identify
your machine.

VEHICLE IDENTIFICATION NUMBER

The vehicle identification number "1" is
stamped on the right of the steering head pipe.

CONSUMER INFORMATION

ENGINE SERIAL NUMBER

The engine serial number "1" is stamped into
the elevated part of the right-side of the engine.

MODEL LABEL

The model label "1" is affixed to the frame un­der the rider's seat. This information will be
needed to order spare parts.

1-3

FEATURES

FEATURES

OUTLINE OF THE FI SYSTEM

The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti­mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera­ture.Inthe conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the
combustionchamber is created by the volume of the intake air and the fuel that is metered by the jet
used in the respective carburetor.
Despite the same volume of intake air, the fuel volume requirement varies by the engine operating
conditions,such as acceleration, deceleration, or operating under a heavy load.Carburetors that me­ter the fuel through the use of jets have been provided with various auxiliary devices, so that an op­timum air fuel ratio can be achieved to accommodate the constant changes in the operating
conditions of the engine.
This model has adopted an electronically controlled fuel injection (FI) system, in place of the conven­tional carburetor system.This system can achieve an optimum air-fuel ratio required by the engine at
all times by using a microprocessor that regulates the fuel injection volume according to the engine
operating conditions detected by various sensors.

1. Fuel injector

2. Throttle position sensor

3. Intake air pressure sensor

4. ECU

5. Fuel pump

6. Intake air temperature sensor

7. Atmospheric pressure sensor

8. Crankshaft position sensor

9. Coolant temperature sensor

10. Ignition coil

11. Condenser

1-4

FEATURES

FI SYSTEM

The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 324 kPa (3.24 kgf/cm ² , 47.0 psi). According­ly,when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens, caus­ing the fuel to be injected into the intake manifold only during the time the passage remains open.
Therefore, the longer the length of time the fuel injector is energized (injection duration), the greater
the volume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector is en­ergized(injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from
the throttle position sensor, coolant temperature sensor, atmospheric pressure sensor, lean angle
sensor, crankshaft position sensor, intake air pressure sensor and intake air temperature sensor en­able the ECU to determine the injection duration. The injection timing is determined through the sig­nals from the rankshaft position sensor. As a result, the volume of fuel that is required by the engine
can be supplied at all times in accordance with the driving conditions.

4

11

10

B

9

8

1. Fuel pump

2. Fuel injector

3. ECU

4. Throttle position sensor

5. Coolant temperature sensor

6. Crankshaft position sensor

7. Intake air pressure sensor

8. Throttle body

9. Intake air temperature sensor

10. Air filter case

C

1

A

2

7

5

11. Atmospheric pressure sensor

A. Fuel system
B. Intake system
C. Control system

3

6

1-5

INCLUDED PARTS

INCLUDED PARTS

DETACHABLE SIDESTAND

This sidestand "1" is used to support only the
machine when standing or transporting it.

• Never apply additional force to the side-

stand.

• Remove this sidestand before starting out.

VALVE JOINT

This valve joint "1" prevents fuel from flowing
out and is installed to the fuel tank breather
hose.

NIPPLE WRENCH

This nipple wrench "1" is used to tighten the
spoke.

HANDLEBAR PROTECTOR

Install the handlebar protector "1" so that the
mark "a" face forward.

In this installation, make sure the arrow fac­es the fuel tank and also downward.

SPARK PLUG WRENCH

This spark plug wrench "1" is used to remove
and install the spark plug.

FUEL TANK HOLDING CABLE

The fuel tank holding cable "1" is used to sup­port the fuel tank during maintenance.

1-6

FUEL HOSE JOINT COVER

The fuel hose joint covers "1" are used to pre­vent mud, dust, and other foreign material from
entering the fuel pump when the fuel hose is
disconnected.

COUPLER FOR CONNECTING OPTIONAL
PART

This coupler "1" is used for connection to an op­tional Power Tuner and so on.

INCLUDED PARTS

When no optional parts, etc. are connected,
connect the connection terminal to the orig­inal coupler "2".
Before removing the coupler, thoroughly
wipe off any mud or water stuck to it.

Part name Part number

GYTR Power Tuner 33D-H59C0-V0-00

The GYTR Power Tuner is optional.

1-7

IMPORTANT INFORMATION

IMPORTANT INFORMATION

PREPARATION FOR REMOVAL AND
DISASSEMBLY

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

• When washing the machine with high pres­sured water, cover the parts follows.
Air duct
Silencer exhaust port
Drain hole on the cylinder head (right side)
Water pump housing hole at the bottom

3. When disassembling the machine, keep
mated parts together. They include gears,
cylinders, pistons, and other mated parts
that have been "mated" through normal
wear. Mated parts must be reused as an as­sembly or replaced.

4. During the machine disassembly, clean all
parts and place them in trays in the order of
disassembly. This will speed up assembly
time and help assure that all parts are cor­rectly reinstalled.

2. Use proper tools and cleaning equipment.
Refer to "SPECIAL TOOLS" section.

5. Keep away from fire.

ALL REPLACEMENT PARTS

1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for as­sembly and adjustment.

GASKETS, OIL SEALS AND O-RINGS

1. All gaskets, oil seals, and O-rings should be
replaced when an engine is overhauled. 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.

1-8

IMPORTANT INFORMATION

LOCK WASHERS/PLATES AND COTTER
PINS

1. All lock washers/plates "1" and cotter pins
must be replaced when they are removed.
Lock tab(s) should be bent along the bolt or
nut flat(s) after the bolt or nut has been prop­erly tightened.

BEARINGS AND OIL SEALS

1. Install the bearing(s) "1" and oil seal(s) "2"
with their manufacturer's marks or numbers
facing outward. (In other words, the
stamped letters must be on the side ex­posed to view.) When installing oil seal(s),
apply a light coating of lightweight lithium
base grease to the seal lip(s). Oil the bear­ings liberally when installing.

CIRCLIPS

1. All circlips should be inspected 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 to the thrust "3" it receives. See the
sectional view.

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

1-9

HANDLING THE ELECTRONIC PARTS

HANDLING THE ELECTRONIC
PARTS

Electronic parts are very sensitive. Handle
with care and do not give impact.

• Mankind has static electricity. It`s voltage
is very high and electronic parts are very
sensitive.

• It is possible that inner small components
of electronic parts are destroyed by static
electricity.

• Do not touch and do not make them dirty.

3. Check:

• All connections

Loose connection → Connect properly.

If the pin "1" on the terminal is flattened, bend it
up.

CHECKING OF CONNECTION

Check the leads, couplers, and connectors for
stains, rust, moisture, etc.

1. Disconnect:

• Lead

• Coupler

• Connector

2. Check:

• Lead

• Coupler

• Connector

Moisture → Dry with an air blower.
Rust/stains → Connect and disconnect sev­eral times.

If the contact seems not good, pull the terminal
by hand and check its condition.

4. Connect:

• Lead

• Coupler

• Connector

Make sure all connections are tight.

1-10

CHECKING OF CONNECTION

5. Check:

•Continuity

(with the pocket tester)

Pocket tester:

90890-03112

Analog pocket tester:

YU-03112-C

• If there is no continuity, clean the terminals.

• When checking the wire harness, perform
steps (1) to (5).

• As a quick remedy, use a contact revitalizer
available at most part stores.

REMOVING THE QUICK FASTENER

Do not push the center pin with too much
force. Otherwise, the center pin could be
damaged.

To remove a quick fastener, push the center pin
in with a screwdriver, then pull the fastener out.

INSTALLING THE QUICK FASTENER

To install a quick fastener, push its center pin
"a" back so that it protrudes from the fastener
head, then insert the fastener and push the pro­truding pin in until it is flush with the fastener
head.

When you check the voltage or electrical conti­nuity, insert the measuring probe from back
side as you can insert from back side.

1. Probe

2. Coupler

1-11

SPECIAL TOOLS

SPECIAL TOOLS

The proper special tools are necessary for complete and accurate tune-up and assembly. Using the
correct special tool will help prevent damage caused by the use of improper tools or improvised tech­niques. The shape and part number used for the special tool differ by country, so two types are pro­vided. Refer to the list provided to avoid errors when placing an order.

• For U.S.A. and Canada, use part number starting with "YM-", "YU-" or "ACC-".

• For others, use part number starting with "90890-".

Tool name/Part number How to use Illustration

Dial gauge and stand
YU-3097, 90890-01252
Stand
YU-1256

These tools are used to check
each part for runout or bend.

Crankshaft installing tool
Crankshaft installing pot
YU-90050, 90890-01274
Crankshaft installing bolt
YU-90050, 90890-01275
Spacer (crankshaft installer)
YM-91044, 90890-04081
Adapter (M12)
YU-90063, 90890-01278

Piston pin puller set
YU-1304, 90890-01304

Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352

These tools are used to install
the crankshaft.

This tool is used to remove
the piston pin.

These tools are used for
checking the cooling system.

1-12

SPECIAL TOOLS

Tool name/Part number How to use Illustration

Steering nut wrench
YU-33975, 90890-01403

This tool is used when tighten
the steering ring nut to speci­fication.

Cap bolt wrench
YM-01500, 90890-01500

Cap bolt ring wrench
YM-01501, 90890-01501

Fork seal driver
YM-A0948, 90890-01502

Spoke nipple wrench
YM-01521, 90890-01521

This tool is used to loosen or
tighten the base valve.

This tool is used to loosen or
tighten the damper assembly.

This tool is used when install
the fork oil seal.

This tool is used to tighten the
spoke.

Pocket tester
YU-03112-C, 90890-03112

Timing light
YM-33277-A, 90890-03141

Use this tool to inspect the
coil resistance, output voltage
and amperage.

This tool is necessary for
checking ignition timing.

1-13

SPECIAL TOOLS

Tool name/Part number How to use Illustration

Pressure gauge.
YU-03153, 90890-03153

This tool is used to measure
the fuel pressure.

FI diagnostic tool
YU-03182, 90890-03182

Fuel pressure adapter
YM-03186, 90890-03186

Test harness S-pressure sen­sor (3P)
YU-03207, 90890-03207

Test harness-speed sensor
(3P)
YU-03208, 90890-03208

This tool is used to check the
fault codes and diagnose any
problems.

This tool is used to attach the
pressure gauge.

This tool is connected be­tween the intake air pressure
sensor and the wire harness
and is used to measure the
voltage.

This tool is connected be­tween the throttle position
sensor and the wire harness
and is used to measure the
voltage.

FI diagnostic tool sub-lead
YU-03212, 90890-03212

Valve guide remover & in­staller set
90890-04016

Valve spring compressor
YM-4019, 90890-04019

This tool is used to connect
the FI diagnostic tool to a bat­tery.

This tool is needed to remove
and install the valve guide.

This tool is needed to remove
and install the valve assem­blies.

1-14

SPECIAL TOOLS

Tool name/Part number How to use Illustration

Clutch holding tool
YM-91042, 90890-04086

This tool is used to hold the
clutch when removing or in­stalling the clutch boss secur­ing nut.

Valve guide remover

5.5 mm (0.22 in)
YM-01122

Valve guide installer

5.5 mm (0.22 in)
YM-04015

Valve guide reamer

5.5 mm (0.22 in)
YM-01196

Valve spring compressor at­tachment
YM-04108, 90890-04108

This tool is needed to remove
and install the valve guide.

This tool is needed to install
the valve guide.

This tool is needed to rebore
the new valve guide.

This tool is needed to remove
and install the valve assem­blies.

Rotor puller
YM-04151, 90890-04151

Crankcase separating tool
YU-A9642
90890-04152

This tool is used to remove
the flywheel magneto.

These tool is used to remove
the crankshaft from either
case.

1-15

SPECIAL TOOLS

Tool name/Part number How to use Illustration

Dynamic spark tester
YM-34487
Ignition checker
90890-06754

This instrument is necessary
for checking the ignition sys­tem components.

Digital tachometer
YU-39951-B, 90890-06760

YAMAHA Bond No. 1215
(ThreeBond
90890-85505

®

No. 1215)

This tool is needed for ob­serving engine rpm.

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

1-16