Yamaha YZ450F Application guide

YZ450F(Z)YZ450F(Z)
20102010
33D-28199-80-E033D-28199-80-E0
OWNER’S SERVICE MANUALOWNER’S SERVICE MANUAL
Read this manual carefully before operating this vehicle.Read this manual carefully before operating this vehicle.

FOREWORD
INTRODUCTION
Congratulations on your purchase of
a Yamaha YZ series. This model is
the culmination of Yamaha's vast ex-
perience in the production of paceset-
ting racing machines. It represents
the highest grade of craftsmanship
and reliability that have made Yama-
ha a leader.
This manual explains operation, in-
spection, basic maintenance and tun-
ing of your machine. If you have any
questions about this manual or your
machine, please contact your Yama-
ha dealer.
Yamaha continually seeks advance-
ments 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.
PLEASE READ THIS MANUAL
CAREFULLY AND COMPLETELY
BEFORE OPERATING THIS MA-
CHINE. DO NOT ATTEMPT TO OP-
ERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTO-
RY KNOWLEDGE OF ITS CON-
TROLS 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 CAPABILI-
TIES AND THE RELIABILITY OF
THIS MACHINE.
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 per-
sonal injury hazards. Obey all safe-
ty 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 in-
jury.
A NOTICE indicates special pre-
cautions that must be taken to
avoid damage to the vehicle or oth-
er property.
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 OPER-
ATED BY AN EXPERIENCED RID-
ER ONLY.
Do not attempt to operate this ma-
chine at maximum power until you
are totally familiar with its character-
istics.
• 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, al-
ways 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 MA-
CHINE IN PROPER WORKING
ORDER.
For safety and reliability, the ma-
chine must be properly maintained.
Always perform the pre-operation
checks indicated in this manual.
Correcting a mechanical problem
before you ride may prevent an ac-
cident.
• GASOLINE IS HIGHLY FLAMMA-
BLE.
Always turn off the engine while re-
fueling. 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 gaso-
line, inhale excess gasoline vapors,
or allow any gasoline to get into
your eyes, contact a doctor immedi-
ately. If any gasoline spills onto
your skin or clothing, immediately
wash skin areas with soap and wa-
ter, 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 poison-
ous. These fumes contain carbon
monoxide, which by itself is odor-
less and colorless. Carbon monox-
ide is a dangerous gas which can
cause unconsciousness or can be
lethal.
• PARK THE MACHINE CAREFUL-
LY; 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 EN-
GINE 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 MA-
CHINE BEFORE TRANSPORTING
IT.
For safety, drain the gasoline from
the fuel tank before transporting the
vehicle.

F.I.M. MACHINE WEIGHTS
Weights of machines without fuel
The minimum weights for motocross
machines are:
for the class 125 cc:
minimum 88 kg (194 lb)
for the class 250 cc:
minimum 98 kg (216 lb)
for the class 500 cc:
minimum 102 kg (225 lb)
In modifying your machine (e.g., for
weight reduction), take note of the
above limits of weight.
HOW TO USE THIS MANUAL
FINDING THE REQUIRED PAGE
1. This manual consists of eight
chapters; "General Information",
"Specifications", "Regular inspec-
tion and adjustments", "Engine",
"Chassis", "Fuel system", "Electri-
cal" and "Tuning".
2. The table of contents is at the be-
ginning of the manual. Look over
the general layout of the book be-
fore 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 de-
scription.
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 me-
chanic with an easy to read, handy
reference that contains comprehen-
sive explanations of all disassembly,
repair, assembly, and inspection op-
erations.
In this revised format, the condition of
a faulty component will precede an
arrow symbol and the course of ac-
tion required will follow the symbol,
e.g.,
• Bearings
Pitting/damage →Replace.

HOW TO READ DESCRIPTIONS
To help identify parts and clarify pro-
cedure steps, there are exploded dia-
grams 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 or-
der of the jobs in the exploded di-
agram. A number that is enclosed
by a circle indicates a disassem-
bly 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" accom-
panies the exploded diagram,
providing the order of jobs, names
of parts, notes in jobs, etc.
5. For jobs requiring more informa-
tion, the step-by-step format sup-
plements "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 appear-
ing 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 current (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 in-
stall new parts.
14. Apply locking agent (LOC-
TITE®)
15. Use new one
1
2
3
4
5

TABLE OF CONTENTS
GENERAL INFORMATION 1
SPECIFICATIONS 2
REGULAR INSPECTION AND
ADJUSTMENTS 3
ENGINE 4
CHASSIS 5
FUEL SYSTEM 6
ELECTRICAL 7
TUNING 8

CONTENTS
CHAPTER 1
GENERAL
INFORMATION
LOCATION OF
IMPORTANT LABELS ..... 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
FEATURES....................... 1-7
INCLUDED PARTS .......... 1-9
IMPORTANT
INFORMATION................. 1-9
HANDLING THE
ELECTRONIC PARTS ... 1-10
CHECKING OF
CONNECTION................ 1-10
SPECIAL TOOLS........... 1-12
CONTROL
FUNCTIONS................... 1-17
STARTING
AND BREAK-IN.............. 1-17
TORQUE-CHECK
POINTS........................... 1-19
CLEANING
AND STORAGE ............. 1-20
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS............ 2-1
MAINTENANCE
SPECIFICATIONS............ 2-3
TIGHTENING
TORQUES ...................... 2-11
LUBRICATION
DIAGRAMS .................... 2-17
CABLE ROUTING
DIAGRAM....................... 2-18
CHAPTER 3
REGULAR
INSPECTION AND
ADJUSTMENTS
MAINTENANCE
INTERVALS......................3-1
PRE-OPERATION
INSPECTION
AND MAINTENANCE.......3-5
ENGINE ............................3-6
CHASSIS ........................3-14
ELECTRICAL .................3-24
CHAPTER 4
ENGINE
SEAT
AND SIDE COVERS.........4-1
EXHAUST PIPE
AND SILENCER ...............4-3
RADIATOR .......................4-7
CAMSHAFTS..................4-10
CYLINDER HEAD...........4-15
VALVES AND
VALVE SPRINGS ...........4-19
CYLINDER
AND PISTON ..................4-23
CLUTCH .........................4-27
OIL FILTER ELEMENT
AND WATER PUMP.......4-31
BALANCER ....................4-35
OIL PUMP.......................4-37
KICK SHAFT
AND SHIFT SHAFT ........4-40
AC MAGNETO................4-45
ENGINE REMOVAL .......4-47
CRANKCASE
AND CRANKSHAFT ......4-52
TRANSMISSION,
SHIFT CAM
AND SHIFT FORK..........4-58
CHAPTER 5
CHASSIS
FRONT WHEEL
AND REAR WHEEL .........5-1
FRONT BRAKE
AND REAR BRAKE..........5-6
FRONT FORK.................5-16
HANDLEBAR..................5-24
STEERING ......................5-28
SWINGARM ....................5-32
REAR
SHOCK ABSORBER......5-37
CHAPTER 6
FUEL SYSTEM
FUEL TANK ......................6-1
THROTTLE BODY............6-4
CHAPTER 7
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM...........7-1
IGNITION SYSTEM...........7-3
THROTTLE POSITION
SENSOR SYSTEM ...........7-6
FUEL INJECTION
SYSTEM............................7-9
FUEL PUMP SYSTEM....7-35
ELECTRICAL
COMPONENTS...............7-36
CHAPTER 8
TUNING
CHASSIS ..........................8-1

1-1
LOCATION OF IMPORTANT LABELS
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS
Please read the following important labels carefully before operating this vehicle.
CANADA
1

1-2
LOCATION OF IMPORTANT LABELS
EUROPE

1-3
LOCATION OF IMPORTANT LABELS
AUS, NZ, ZA

1-4
LOCATION OF IMPORTANT LABELS
Familiarize yourself with the following pictograms and read the explanatory text.
Read Owner's service manual.
This unit contains high-pressure nitrogen gas. Mishandling can cause explosion. Do not incinerate,
puncture or open.
Turn off the main switch after riding to avoid draining the battery.
Use unleaded gasoline only.
Measure tire pressure when tires are cold.
Adjust tire pressure.
Improper tire pressure can cause loss of control.
Loss of control can result in severe injury or death.

1-5
DESCRIPTION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
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
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

1-6
CONSUMER INFORMATION
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 au-
thorities will need the number to
search for and identify your ma-
chine.
VEHICLE IDENTIFICATION
NUMBER
The vehicle identification number "1"
is stamped on the right of the steering
head pipe.
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 in-
formation will be needed to order
spare parts.

1-7
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 ac-
cordance with the engine operating conditions and the atmospheric temperature. In the 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 ac-
celeration, deceleration, or operating under a heavy load. Carburetors that meter thefuel 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 sys-
tem. This system can achieve an optimum air-fuel ratio required bythe engine at all times by using a microprocessor that
regulates the fuel injection volume according tothe 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

1-8
FEATURES
FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains thefuel 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, causingthe 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 (in-
jection 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 crankshaft 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.
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
11. Atmospheric pressure sensor
A. Fuel system
B. Intake system
C. Control system
1
10
9
B
87
6
5
A
2
3
C
4
11

1-9
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 sidestand.
• 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.
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.
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.
FUEL TANK HOLDING CABLE
The fuel tank holding cable "1" is
used to support the fuel tank during
maintenance.
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 discon-
nected.
COUPLER FOR CONNECTING
OPTIONAL PART
This coupler "1" is used for connec-
tion to an optional Power Tuner and
so on.
When no optional parts, etc. are
connected, connect the connec-
tion terminal to the original cou-
pler "2".
Before removing the coupler, thor-
oughly wipe off any mud or water
stuck to it.
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
2. Use proper tools and cleaning
equipment. Refer to "SPECIAL
TOOLS" section.
3. When disassembling the ma-
chine, 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 re-
placed.
Part name Part number
YZ Power Tuner 33D-859C0-10
The YZ Power Tuner is optional.

1-10
HANDLING THE ELECTRONIC PARTS
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.
5. Keep away from fire.
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha
genuine parts for all replace-
ments. Use oil and/or grease rec-
ommended 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 en-
gine is overhauled. All gasket sur-
faces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and
bearings during reassembly. Ap-
ply grease to the oil seal lips.
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 manufactur-
er's marks or numbers facing out-
ward. (In other words, the
stamped letters must be on the
side exposed to view.) When in-
stalling oil seal(s), apply a light
coating of lightweight lithium base
grease to the seal lip(s). Oil the
bearings liberally when installing.
Do not use compressed air to spin
the bearings dry. This causes dam-
age to the bearing surfaces.
CIRCLIPS
1. All circlips should be inspected
carefully before reassembly. Al-
ways replace piston pin clips after
one use. Replace distorted cir-
clips. 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.
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 elec-
tronic parts are very sensitive.
• It is possible that inner small
components of electronic parts
are destroyed by static electrici-
ty.
• Do not touch and do not make
them dirty.
CHECKING OF
CONNECTION
Check the leads, couplers, and con-
nectors for stains, rust, moisture, etc.
1. Disconnect:
•Lead
• Coupler
• Connector
2. Check:
•Lead
• Coupler
• Connector
Moisture →Dry with an air blow-
er.
Rust/stains →Connect and dis-
connect several times.
3. Check:
• All connections
Loose connection →Connect
properly.
If the pin "1" on the terminal is flat-
tened, bend it up.

1-11
CHECKING OF CONNECTION
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.
5. Check:
• Continuity
(with the pocket tester)
• 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.
When you check the voltage or elec-
trical continuity, insert the measuring
probe from back side as you can in-
sert from back side.
1. Probe
2. Coupler
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.
Pocket tester:
90890-03112
Analog pocket tester:
YU-03112-C

1-12
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
These tools are used to install the
crankshaft.
Piston pin puller set
YU-1304, 90890-01304
This tool is used to remove the pis-
ton pin.
Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352
These tools are used for checking
the cooling system.
Steering nut wrench
YU-33975, 90890-01403
This tool is used when tighten the
steering ring nut to specification.

1-13
SPECIAL TOOLS
Cap bolt wrench
YM-01500, 90890-01500
This tool is used to loosen or tighten
the base valve.
Cap bolt ring wrench
YM-01501, 90890-01501
This tool is used to loosen or tighten
the damper assembly.
Fork seal driver
YM-A0948, 90890-01502
This tool is used when install the fork
oil seal.
Spoke nipple wrench
YM-01521, 90890-01521
This tool is used to tighten the
spoke.
Pocket tester
YU-03112-C, 90890-03112
Use this tool to inspect the coil resis-
tance, output voltage and amper-
age.
Timing light
YM-33277-A, 90890-03141
This tool is necessary for checking
ignition timing.
Pressure gauge.
YU-03153, 90890-03153
This tool is used to measure the fuel
pressure.
Tool name/Part number How to use Illustration

1-14
SPECIAL TOOLS
FI diagnostic tool
YU-03182, 90890-03182
This tool is used to check the fault
codes and diagnose any problems.
Fuel pressure adapter
YM-03186, 90890-03186
This tool is used to attach the pres-
sure gauge.
Test harness S-pressure sensor
(3P)
YU-03207, 90890-03207
This tool is connected between the
intake air pressure sensor and the
wire harness and is used to mea-
sure the voltage.
Test harness-speed sensor (3P)
YU-03208, 90890-03208
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
This tool is used to connect the FI di-
agnostic tool to a battery.
Valve guide remover & installer set
90890-04016
This tool is needed to remove and
install the valve guide.
Valve spring compressor
YM-4019, 90890-04019
This tool is needed to remove and
install the valve assemblies.
Clutch holding tool
YM-91042, 90890-04086
This tool is used to hold the clutch
when removing or installing the
clutch boss securing nut.
Tool name/Part number How to use Illustration