Yamaha YZ450 Y 2009 Owner's manual

2009

Read this manual carefully before operating this vehicle.

Il convient de lire attentivement ce manuel avant la première utilisation du véhicule.

Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen.

OWNER’S SERVICE MANUAL

MANUEL D’ATELIER DU

PROPRIETAIRE

FAHRER- UND

WARTUNGSHANDBUCH

YZ450F(Y)

34P-28199-80

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

Il convient de lire attentivement ce manuel avant la première utilisation du véhicule. Le manuel doit être remis avec le véhicule en cas de vente de ce dernier.

Bitte lesen Sie diese Bedienungsanleitung sorgfältig durch, bevor Sie das Fahrzeug in Betrieb nehmen. Diese Bedienungsanleitung muss, wenn das Fahrzeug verkauft wird, beim Fahrzeug verbleiben.

Read this manual carefully before operating this vehicle.Read this manual carefully before operating this vehicle.

20092009

OWNER’S SERVICE MANUALOWNER’S SERVICE MANUAL

YZ450F(Y)YZ450F(Y)

34P-28199-80-E034P-28199-80-E0

YZ450F(Y)

OWNER'S SERVICE MANUAL

1st Edition, May 2008

unauthorized use without the written

permission of Yamaha Motor Co., Ltd.

is expressly prohibited.

Printed in Japan

FOREWORD

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.

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.

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.

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 pre-operation 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. When transporting the machine in another vehicle, always be sure it is properly secured and in an upright position and that the fuel cock is in the "OFF" position. Otherwise, fuel may leak out of the carburetor or fuel tank.

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 seven chapters; "General Information", "Specifications", "Regular inspection and adjustments", "Engine", "Chassis", "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, stepby-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 or-

der 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 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 install new parts.

14. Apply locking agent (LOC-

15. Use new one

TITE

)

TABLE OF CONTENTS

GENERAL INFORMATION

SPECIFICATIONS

REGULAR INSPECTION AND ADJUSTMENTS

ENGINE

CHASSIS

ELECTRICAL

TUNING

CONTENTS

CHAPTER 1

GENERAL

INFORMATION

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

MACHINE

IDENTIFICATION ............. 1-2

INCLUDED PARTS .......... 1-2

IMPORTANT

INFORMATION................. 1-2

CHECKING OF

CONNECTION.................. 1-3

SPECIAL TOOLS ............. 1-4

CONTROL FUNCTIONS .. 1-8 STARTING AND

BREAK-IN ........................ 1-8

TORQUE-CHECK

POINTS........................... 1-11

CLEANING AND

STORAGE ...................... 1-12

CHAPTER 2

SPECIFICATIONS

GENERAL

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

MAINTENANCE

SPECIFICATIONS............ 2-3

TIGHTENING

TORQUES ...................... 2-10

LUBRICATION

DIAGRAMS .................... 2-16

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, FUEL TANK AND

SIDE COVERS..................4-1

EXHAUST PIPE AND

SILENCER ........................ 4-3

RADIATOR .......................4-5

CARBURETOR................. 4-7

CAMSHAFTS.................. 4-14

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

VALVES AND

VALVE SPRINGS ...........4-22

CYLINDER AND

PISTON...........................4-26

CLUTCH .........................4-29

OIL FILTER ELEMENT

AND WATER PUMP.......4-33

BALANCER ....................4-37

OIL PUMP ....................... 4-39

KICK SHAFT AND

SHIFT SHAFT ................. 4-42

CDI MAGNETO............... 4-47

ENGINE REMOVAL ....... 4-49

CRANKCASE AND

CRANKSHAFT ............... 4-53

TRANSMISSION, SHIFT CAM AND

SHIFT FORK................... 4-59

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 ....................5-31

REAR SHOCK

ABSORBER ....................5-36

CHAPTER 6

ELECTRICAL

ELECTRICAL COMPONENTS AND

WIRING DIAGRAM...........6-2

IGNITION SYSTEM...........6-3

THROTTLE POSITION

SENSOR SYSTEM ...........6-6

CHAPTER 7

TUNING

ENGINE.............................7-1

CHASSIS ..........................7-6

GENERAL INFORMATION

DESCRIPTION

1. Clutch lever

2. Hot starter lever

3. Front brake lever

4. Throttle grip

5. Radiator cap

6. Fuel tank cap

7. Engine stop switch

8. Kickstarter crank

9. Fuel tank

10. Radiator

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

• Designs and specifications are subject to change without notice.

11. Coolant drain bolt

12. Rear brake pedal

13. Valve joint

14. Fuel cock

15. Cold starter knob

16. Drive chain

17. Air cleaner

18. Shift pedal

19. Oil dipstick

20. Front fork

1-1

MACHINE IDENTIFICATION

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.

MACHINE IDENTIFICATION

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.

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. Silencer exhaust port Side cover air intake port Water pump housing hole at the bottom Drain hole on the cylinder head (right side)

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.

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.

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.

JET NEEDLE PULL-UP TOOL

The jet needle pull-up tool "1" is used to pull the jet needle out of the carburetor.

HANDLEBAR PROTECTOR

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

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

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.

1-2

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 replacements. Use oil and/or grease recommended by Yamaha for assembly and adjustment.

GASKETS, OIL SEALS AND ORINGS

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.

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.

CHECKING OF CONNECTION

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.

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

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.

3. Connect and disconnect the connector two or three times.

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

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

6. Connect:

• Connector

The two connectors "click" together.

7. Check for continuity with a tester.

• If there in no continuity, clean the

terminals.

• Be sure to perform the steps 1 to 7

listed above when checking the wire harness.

• For a field remedy, use a contact re-

vitalizer available on the market.

• Use the tester on the connector as

shown.

CHECKING OF CONNECTION

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

1. Disconnect:

• Connector

2. Dry each terminal with an air blower.

1-3

SPECIAL TOOLS

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.

SPECIAL TOOLS

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.

Rotor puller YM-04151, 90890-04151

Steering nut wrench YU-33975, 90890-01403

This tool is used to remove the flywheel magneto.

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

1-4

SPECIAL TOOLS

Tool name/Part number How to use Illustration

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

Fork seal driver YM-A0948, 90890-01502

Spoke nipple wrench YM-01521, 90890-01521

Pocket tester YU-3112-C, 90890-03112

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.

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

Timing light YM-33277-A, 90890-03141

Valve spring compressor YM-4019, 90890-04019

This tool is necessary for checking ignition timing.

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

1-5

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 Intake 4.5 mm (0.18 in) Exhaust 5.0 mm (0.20 in) YM-4116, 90890-04116 YM-4097, 90890-04097

Valve guide installer Intake 4.5 mm (0.18 in) Exhaust 5.0 mm (0.20 in) YM-4117, 90890-04117 YM-4098, 90890-04098

Valve guide reamer Intake 4.5 mm (0.18 in) Exhaust 5.0 mm (0.20 in) YM-4118, 90890-04118 YM-4099, 90890-04099

Crankcase separating tool YU-A9642 90890-04152

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.

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

Dynamic spark tester YM-34487 Ignition checker 90890-06754

This instrument is necessary for checking the ignition system components.

1-6

SPECIAL TOOLS

Tool name/Part number How to use Illustration

Digital tachometer YU-39951-B, 90890-06760

This tool is needed for observing engine rpm.

YAMAHA Bond No. 1215 (ThreeBond® No. 1215) 90890-85505

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

1-7

CONTROL FUNCTIONS

ENGINE STOP SWITCH

The engine stop switch "1" is located on the left handlebar. Continue pushing the engine stop switch till the engine comes to a stop.

CONTROL FUNCTIONS

CLUTCH LEVER

The clutch lever "1" is located on the left handlebar; it disengages or engages the clutch. Pull the clutch lever to the handlebar to disengage the clutch, and release the lever to engage the clutch. The lever should be pulled rapidly and released slowly for smooth starts.

SHIFT PEDAL

The gear ratios of the constant-mesh 5 speed transmission are ideally spaced. The gears can be shifted by using the shift pedal "1" on the left side of the engine.

THROTTLE GRIP

The throttle grip "1" is located on the right handlebar; it accelerates or decelerates the engine. For acceleration, turn the grip toward you; for deceleration, turn it away from you.

FRONT BRAKE LEVER

The front brake lever "1" is located on the right handlebar. Pull it toward the handlebar to activate the front brake.

REAR BRAKE PEDAL

The rear brake pedal "1" is located on the right side of the machine. Press down on the brake pedal to activate the rear brake.

COLD STARTER KNOB

When cold, the engine requires a richer air-fuel mixture for starting. A separate starter circuit, which is controlled by the cold starter knob "1", supplies this mixture. Pull the cold starter knob out to open the circuit for starting. When the engine has warmed up, push it in to close the circuit.

HOT STARTER LEVER

The hot starter lever "1" is used when starting a warm engine. Use the hot starter lever when starting the engine again immediately after it was stopped (the engine is still warm). Pulling the hot starter lever injects secondary air to thin the air-fuel mixture temporarily, allowing the engine to be started more easily.

KICKSTARTER CRANK

Rotate the kickstarter crank "1" away from the engine. Push the starter down lightly with your foot until the gears engage, then kick smoothly and forcefully to start the engine. This model has a primary kickstarter crank so the engine can be started in any gear if the clutch is disengaged. In normal practices, however, shift to neutral before starting.

FUEL COCK

The fuel cock supplies fuel from the tank to carburetor and also filters the fuel. The fuel cock has the two positions: OFF: With the lever in this position, fuel will not flow. Always return the lever to this position when the engine is not running. ON: With the lever in this position, fuel flows to the carburetor. Normal riding is done with the lever in this position.

1-8

STARTING AND BREAK-IN

FUEL

Always use the recommended fuel as stated below. Also, be sure to use new gasoline the day of a race.

Recommended fuel:

Premium unleaded gasoline only with a research octane number of 95 or higher.

Use only unleaded gasoline. The use of leaded gasoline will cause severe damage to the engine internal parts such as valves, piston rings, and exhaust system, etc.

If knocking or pinging occurs, use a different brand of gasoline or higher octane grade.

• For refueling, be sure to stop the engine and use enough care not to spill any fuel. Also be sure to avoid refueling close to a fire.

• Refuel after the engine, exhaust pipe, etc. have cooled off.

HANDLING NOTE

Never start or run the engine in a closed area. The exhaust fumes are poisonous; they can cause loss of consciousness and death in a very short time. Always operate the machine in a well-ventilated area.

• The carburetor on this machine has a built-in accelerator pump. Therefore, when starting the engine, do not operate the throttle or the spark plug will foul.

• Unlike a two-stroke engine, this engine cannot be kick started when the throttle is open because the kickstarter may kick back. Also, if the throttle is open the air/fuel mixture may be too lean for the engine to start.

• Before starting the machine, perform the checks in the pre-operation check list.

AIR FILTER MAINTENANCE

According to "CLEANING THE AIR FILTER ELEMENT" section in the CHAPTER 3, apply the foam-air-filter oil or its equivalent to the element. (Excess oil in the element may adversely affect engine starting.)

STARTING A COLD ENGINE

1. Inspect the coolant level.

2. Turn the fuel cock to "ON".

3. Shift the transmission into neutral.

4. Fully open the cold starter knob

"1".

5. Kick the kickstarter crank.

STARTING AND BREAK-IN

Do not open the throttle while kicking the kickstarter crank. Otherwise, the kickstarter crank may kick back.

6. Return the cold starter knob to its original position and run the engine at 3,000–5,000 r/min for 1 or 2 minutes.

Since this model is equipped with an accelerator pump, if the engine is raced (the throttle opened and closed), the air/fuel mixture will be too rich and the engine may stall. Also unlike a two-stroke engine, this model can idle.

Do not warm up the engine for extended periods of time.

STARTING A WARM ENGINE

Do not operate the cold starter knob and throttle. Pull the hot starter lever "1" and start the engine by kicking the kickstarter crank forcefully with a firm stroke. As soon as the engine starts, release the hot starter lever to close the air passage.

Restarting an engine after a fall

Pull the hot starter lever and start the engine. As soon as the engine starts, release the hot starter lever to close the air passage.

The engine fails to start

Pull the hot starter lever all the way out and while holding the lever, kick the kickstarter crank 10 to 20 times to clear the engine. Then, restart the engine. Refer to "Restarting an engine after a fall".

Thrott

Cold

grip

oper-

ation*

Air temperature = less than 5 °C (41 °F)

Air temperature = more than 5 °C (41 °F)

Star ting

Air tem-

perature

cold

(normal

en-

tempera-

gine

ture) = between 5 °C (41 °F) and 25 °C (77 °F)

Air temperature = more than 25 °C (77 °F)

Starting an engine after a long period of time

Restarting a warm engine

Restarting an engine after a fall

* Operate the throttle grip before kick starting.

Open

3 or 4

times

None ON OFF

None

None OFF OFF

None ON OFF

None OFF ON

Hot

start-

er le-

knob

ON OFF

ON/

OFF

ver

Observe the following break-in procedures during initial operation to ensure optimum performance and avoid engine damage.

1-9

BREAK-IN PROCEDURES

1. Before starting the engine, fill the fuel tank with the fuel.

2. Perform the pre-operation checks on the machine.

3. Start and warm up the engine. Check the idle speed, and check the operation of the controls and the engine stop switch. Then, restart the engine and check its operation within no more than 5 minutes after it is restarted.

4. Operate the machine in the lower gears at moderate throttle openings for five to eight minutes.

5. Check how the engine runs when the machine is ridden with the throttle 1/4 to 1/2 open (low to medium speed) for about one hour.

6. Restart the engine and check the operation of the machine throughout its entire operating range. Restart the machine and operate it for about 10 to 15 more minutes. The machine will now be ready to race.

STARTING AND BREAK-IN

• After the break-in or before each

race, you must check the entire machine for loose fittings and fasteners as per "TORQUECHECK POINTS". Tighten all such fasteners as required.

• When any of the following parts

have been replaced, they must be broken in. CYLINDER AND CRANKSHAFT: About one hour of break-in operation is necessary. PISTON, RING, VALVES, CAMSHAFTS AND GEARS: These parts require about 30 minutes of break-in operation at half-throttle or less. Observe the condition of the engine carefully during operation.

1-10

TORQUE-CHECK POINTS

Frame construction Frame to rear frame

Combined seat and fuel tank Fuel tank to frame

Exhaust system Silencer to rear frame

Engine mounting Frame to engine

Engine bracket to engine

Engine bracket to frame

Steering Steering stem to handlebar Steering stem to frame

Steering stem to upper bracket

Upper bracket to handlebar

Suspension Front Steering stem to front fork Front fork to upper bracket

Front fork to lower bracket

Rear For link type Assembly of links

Link to frame

Link to rear shock absorber

Link to swingarm

Installation of rear shock absorber Rear shock absorber to frame

Installation of swingarm Tightening of pivot shaft

Wheel Installation of wheel Front Tightening of wheel axle

Tightening of axle holder

Rear Tightening of wheel axle

Wheel to rear wheel sprocket

Brake Front Brake caliper to front fork

Brake disc to wheel

Tightening of union bolt

Brake master cylinder to handlebar

Tightening of bleed screw

Tightening of brake hose holder

Rear Brake pedal to frame

Brake disc to wheel

Tightening of union bolt

Brake master cylinder to frame

Tightening of bleed screw

Tightening of brake hose holder

Fuel system Fuel tank to fuel cock

Lubrication system Tightening of oil hose clamp

Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2.

1-11

CLEANING AND STORAGE

CLEANING

Frequent cleaning of your machine will enhance its appearance, maintain good overall performance, and extend the life of many components.

1. Before washing the machine, block off the end of the exhaust pipe to prevent water from entering. A plastic bag secured with a rubber band may be used for this purpose.

2. If the engine is excessively greasy, apply some degreaser to it with a paint brush. Do not apply degreaser to the chain, sprockets, or wheel axles.

3. Rinse the dirt and degreaser off with a garden hose; use only enough pressure to do the job.

Excessive hose pressure may cause water seepage and contamination of wheel bearings, front forks, brakes and transmission seals. Many expensive repair bills have resulted from improper high pressure detergent applications such as those available in coin-operated car washers.

4. After the majority of the dirt has been hosed off, wash all surfaces with warm water and a mild detergent. Use an old toothbrush to clean hard-to-reach places.

5. Rinse the machine off immediately with clean water, and dry all surfaces with a soft towel or cloth.

6. Immediately after washing, remove excess water from the chain with a paper towel and lubricate the chain to prevent rust.

7. Clean the seat with a vinyl upholstery cleaner to keep the cover pliable and glossy.

8. Automotive wax may be applied to all painted or chromed surfaces. Avoid combination cleanerwaxes, as they may contain abrasives.

9. After completing the above, start the engine and allow it to idle for several minutes.

STORAGE

If your machine is to be stored for 60 days or more, some preventive measures must be taken to avoid deterioration. After cleaning the machine thoroughly, prepare it for storage as follows:

1. Drain the fuel tank, fuel lines, and the carburetor float bowl.

2. Remove the spark plug, pour a tablespoon of SAE 10W-30 motor oil in the spark plug hole, and reinstall the plug. With the engine stop switch pushed in, kick the engine over several times to coat the cylinder walls with oil.

3. Remove the drive chain, clean it thoroughly with solvent, and lubricate it. Reinstall the chain or store it in a plastic bag tied to the frame.

4. Lubricate all control cables.

5. Block the frame up to raise the wheels off the ground.

6. Tie a plastic bag over the exhaust pipe outlet to prevent moisture from entering.

7. If the machine is to be stored in a humid or salt-air environment, coat all exposed metal surfaces with a film of light oil. Do not apply oil to rubber parts or the seat cover.

Make any necessary repairs before the machine is stored.

1-12

GENERAL SPECIFICATIONS

SPECIFICATIONS

GENERAL SPECIFICATIONS

Model name: YZ450FY (USA, CDN, AUS, NZ)

YZ450F (EUROPE, ZA)

Model code number: 34P1 (USA,CDN)

34P2 (EUROPE)

34P4 (AUS, NZ, ZA)

Dimensions: USA, CDN, AUS, NZ, ZA EUROPE

Overall length 2,195 mm (86.42 in) 2,196 mm (86.46 in)

Overall width 825 mm (32.48 in) ←

Overall height 1,305 mm (51.38 in) ←

Seat height 989 mm (38.94 in) 1,000 mm (39.37 in)

Wheelbase 1,496 mm (58.90 in) ←

Minimum ground clearance 373 mm (14.69 in) 374 mm (14.72 in)

Dry weight:

Without oil and fuel 99.0 kg (218 lb)

Engine:

Engine type Liquid cooled 4-stroke, DOHC

Cylinder arrangement Single cylinder, forward inclined

Displacement 449 cm

Bore × stroke 95.0 × 63.4 mm (3.74 × 2.50 in)

Compression ratio 12.3 : 1

Starting system Kickstarter

Lubrication system: Dry sump

Oil type or grade:

Engine oil (For USA and CDN)

Yamalube 4, SAE10W-40 or SAE20W-50

Yamalube 4-R, SAE10W-50

API service SG type or higher,

JASO standard MA

(15.8 Imp oz, 15.2 US oz)

(Except for USA and CDN)

SAE10W-30, SAE10W-40, SAE15W-40,

SAE20W-40 or SAE20W-50

API service SG type or higher,

JASO standard MA

Oil capacity:

Engine oil

Periodic oil change 0.95 L (0.84 Imp qt, 1.00 US qt)

With oil filter replacement 1.0 L (0.88 Imp qt, 1.06 US qt)

Total amount 1.2 L (1.06 Imp qt, 1.27 US qt)

Coolant capacity (including all routes): 0.99 L (0.87 Imp qt, 1.05 US qt)

Air filter: Wet type element

2-1

GENERAL SPECIFICATIONS

Fuel:

Type Premium unleaded gasoline only with a research octane

number of 95 or higher.

Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal)

Carburetor:

Type FCR-MX39

Manufacturer KEIHIN

Spark plug:

Type/manufacturer CR8E/NGK (resistance type)

Gap 0.7–0.8 mm (0.028–0.031 in)

Clutch type: Wet, multiple-disc

Transmission:

Primary reduction system Gear

Primary reduction ratio 61/23 (2.652)

Secondary reduction system Chain drive

Secondary reduction ratio 49/13 (3.769)

Transmission type Constant mesh, 5-speed

Operation Left foot operation

Gear ratio:

1st 27/14 (1.929)

2nd 23/15 (1.533)

3rd 23/18 (1.278)

4th 24/22 (1.091)

5th 20/21 (0.952)

Chassis: USA, CDN, AUS, NZ, ZA EUROPE

Frame type Semi double cradle ←

Caster angle 26.9° 26.8°

Trail 115.7 mm (4.56 in) 114.2 mm (4.50 in)

Tire:

Type With tube

Size (front) 80/100-21 51M

Size (rear) 120/80-19 63M (For USA, CDN, ZA, AUS, NZ)

110/90-19 62M (For EUROPE)

Tire pressure (front and rear) 100 kPa (1.0 kgf/cm

Brake:

Front brake type Single disc brake

Operation Right hand operation

Rear brake type Single disc brake

Operation Right foot operation

Suspension:

Front suspension Telescopic fork

Rear suspension Swingarm (link type monocross suspension)

Shock absorber:

Front shock absorber Coil spring/oil damper

Rear shock absorber Coil spring/gas, oil damper

, 15 psi)

2-2

MAINTENANCE SPECIFICATIONS

Wheel travel:

Front wheel travel 300 mm (11.8 in)

Rear wheel travel 314 mm (12.4 in)

Electrical:

Ignition system CDI magneto

MAINTENANCE SPECIFICATIONS

ENGINE

Item Standard Limit

Cylinder head:

Warp limit ---- 0.05 mm (0.002

in)

Cylinder:

Bore size 95.00–95.01 mm (3.7402–3.7406 in) ----

Out of round limit ---- 0.05 mm (0.002

in)

Camshaft:

Drive method Chain drive (Left) ----

Camshaft cap inside diameter 22.000–22.021 mm (0.8661–0.8670 in) ----

Camshaft outside diameter 21.959–21.972 mm (0.8645–0.8650 in) ----

Shaft-to-cap clearance 0.028–0.062 mm (0.0011–0.0024 in) 0.08 mm (0.003

in)

Cam dimensions

Intake "A" 31.200–31.300 mm (1.2283–1.2323 in) 31.100 mm

(1.2244 in)

Intake "B" 22.550–22.650 mm (0.8878–0.8917 in) 22.450 mm

(0.8839 in)

Exhaust "A" 30.900–31.000 mm (1.2165–1.2205 in) 30.800 mm

(1.2126 in)

Exhaust "B" 22.468–22.568 mm (0.8846–0.8885 in) 22.368 mm

(0.8806 in)

Camshaft runout limit ---- 0.03 mm

(0.0012 in)

2-3

MAINTENANCE SPECIFICATIONS

Item Standard Limit

Timing chain:

Timing chain type/No. of links 98XRH2010-118M/118 ----

Timing chain adjustment method Automatic ----

Valve, valve seat, valve guide:

Valve clearance (cold)

IN 0.10–0.15 mm (0.0039–0.0059 in) ----

EX 0.20–0.25 mm (0.0079–0.0098 in) ----

Valve dimensions:

"A" head diameter (IN) 26.9–27.1 mm (1.0591–1.0669 in) ----

"A" head diameter (EX) 27.9–28.1 mm (1.0984–1.1063 in) ----

"B" face width (IN) 2.26 mm (0.089 in) ----

"B" face width (EX) 2.26 mm (0.089 in) ----

"C" seat width (IN) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630

in)

"C" seat width (EX) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630

in)

"D" margin thickness (IN) 1 mm (0.0394 in) 0.85 mm (0.033

in)

"D" margin thickness (EX) 1 mm (0.0394 in) 0.85 mm (0.033

in)

Stem outside diameter (IN) 4.475–4.490 mm (0.1762–0.1768 in) 4.445 mm

(0.1750 in)

Stem outside diameter (EX) 4.965–4.980 mm (0.1955–0.1961 in) 4.935 mm

(0.1943 in)

Guide inside diameter (IN) 4.500–4.512 mm (0.1772–0.1776 in) 4.550 mm

(0.1791 in)

Guide inside diameter (EX) 5.000–5.012 mm (0.1969–0.1973 in) 5.050 mm

(0.1988 in)

2-4

MAINTENANCE SPECIFICATIONS

Item Standard Limit

Stem-to-guide clearance (IN) 0.010–0.037 mm (0.0004–0.0015 in) 0.08 mm (0.003

in)

Stem-to-guide clearance (EX) 0.020–0.047 mm (0.0008–0.0019 in) 0.10 mm (0.004

in)

Stem runout limit ---- 0.01 mm

(0.0004 in)

Valve seat width (IN) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630

in)

Valve seat width (EX) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630

in)

Valve spring:

Free length (IN) 37.03 mm (1.46 in) 36.03 mm (1.42

in)

Free length (EX) 37.68 mm (1.48 in) 36.68 mm (1.44

in)

Set length (valve closed) (IN) 27.87 mm (1.10 in) ----

Set length (valve closed) (EX) 27.38 mm (1.08 in) ----

Compressed force (installed) (IN) 111.3–127.9 N at 27.87 mm (11.3–13.0 kg

at 27.87 mm, 24.91–28.66 lb at 1.10 in)

Compressed force (installed) (EX) 127.4–146.4 N at 27.38 mm (13.0–14.9 kg

at 27.38 mm, 28.66–32.85 lb at 1.08 in)

Tilt limit* (IN) ---- 2.5°/1.61 mm

Tilt limit* (EX) ---- 2.5°/1.65 mm

----

(2.5°/0.063 in)

(2.5°/0.065 in)

Direction of winding (top view) (IN) Clockwise ----

Direction of winding (top view) (EX) Clockwise ----

Piston:

Piston to cylinder clearance 0.020–0.045 mm (0.0008–0.0018 in) 0.1 mm (0.004

in)

Piston size "D" 94.965–94.980 mm (3.7388–3.7394 in) ----

Measuring point "H" 8 mm (0.315 in) ----

2-5

MAINTENANCE SPECIFICATIONS

Item Standard Limit

Piston off-set 1 mm (0.0394 in) ----

Piston pin bore inside diameter 18.004–18.015 mm (0.7088–0.7093 in) 18.045 mm

(0.7104 in)

Piston pin outside diameter 17.991–18.000 mm (0.7083–0.7087 in) 17.971 mm

(0.7075 in)

Piston rings:

Top ring:

Type Barrel ----

Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ----

End gap (installed) 0.20–0.30 mm (0.008–0.012 in) 0.55 mm (0.022

in)

Side clearance (installed) 0.030–0.065 mm (0.0012–0.0026 in) 0.12 mm (0.005

in)

2nd ring:

Type Taper ----

Dimensions (B × T) 1.00 × 3.35 mm (0.04 × 0.13 in) ----

End gap (installed) 0.35–0.50 mm (0.014–0.020 in) 0.85 mm (0.033

in)

Side clearance 0.020–0.055 mm (0.0008–0.0022 in) 0.12 mm (0.005

in)

Oil ring:

Dimensions (B × T) 2.0 × 2.9 mm (0.08 × 0.11 in) ----

End gap (installed) 0.2–0.5 mm (0.01–0.02 in) ----

Crankshaft:

Crank width "A" 61.95–62.00 mm (2.439–2.441 in) ----

Runout limit "C" 0.03 mm (0.0012 in) 0.05 mm (0.002

in)

Big end side clearance "D" 0.15–0.45 mm (0.0059–0.0177 in) 0.50 mm (0.02

in)

Small end free play "F" 0.4–1.0 mm (0.02–0.04 in) 2.0 mm (0.08

in)

Balancer:

Balancer drive method Gear ----

2-6

MAINTENANCE SPECIFICATIONS

Item Standard Limit

Air filter oil grade: Foam-air-filter oil or equivalent oil ----

Clutch:

Friction plate thickness 2.92–3.08 mm (0.115–0.121 in) 2.8 mm (0.110

in)

Quantity 8 ----

Clutch plate thickness 1.5–1.7 mm (0.059–0.067 in) ----

Quantity 7 ----

Warp limit ---- 0.1 mm (0.004

in)

Clutch spring free length 50.0 mm (1.97 in) 49.0 mm (1.93

in)

Quantity 6 ----

Clutch housing thrust clearance 0.10–0.35 mm (0.0039–0.0138 in) ----

Clutch housing radial clearance 0.010–0.044 mm (0.0004–0.0017 in) ----

Clutch release method Inner push, cam push ----

Shifter:

Shifter type Cam drum and guide bar ----

Guide bar bending limit ---- 0.05 mm (0.002

in)

Kickstarter:

Type Kick and ratchet type ----

Carburetor:

Type/manufacturer FCR-MX39/KEIHIN ----

I. D. mark 2S2B B0 ----

Main jet (M.J) #160 ----

Main air jet (M.A.J) ø2.0 ----

Jet needle - clip position (J.N) NFLR-3 ----

Cutaway (C.A) 1.5 ----

Pilot jet (P.J) #45 ----

Pilot air jet (P.A.J) #100 ----

Pilot outlet (P.O) ø0.9 ----

Pilot screw (example) (P.S) 1-1/2 ----

Bypass (B.P) ø1.0 ----

Valve seat size (V.S) ø3.8 ----

Starter jet (G.S) #72 ----

Leak jet (Acc.P) #55 ----

Float height (F.H) 8 mm (0.31 in) ----

Engine idle speed 1,900–2,100 r/min ----

Intake vacuum 28.0–33.3 kPa (210–250 mmHg, 8.27–

9.84 inHg)

Hot starter lever free play 3–6 mm (0.12–0.24 in) ----

----

2-7

MAINTENANCE SPECIFICATIONS

Item Standard Limit

Lubrication system:

Oil filter type Paper type ----

Oil pump type Trochoid type ----

Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008

in)

Side clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009

in)

Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm (0.007

in)

Bypass valve setting pressure 40–80 kPa (0.4–0.8 kg/cm

psi)

Cooling:

Radiator core size

Width 120.2 mm (4.73 in) ----

Height 240 mm (9.45 in) ----

Thickness 22 mm (0.87 in) ----

Radiator cap opening pressure 110 kPa (1.1 kg/cm

Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt) ----

Water pump

Type Single-suction centrifugal pump ----

CHASSIS

, 5.69–11.38

, 15.6 psi) ----

----

Item Standard Limit

Steering system:

Steering bearing type Taper roller bearing ----

Front suspension: USA, CDN EUROPE, AUS, NZ, ZA

Front fork travel 300 mm (11.8 in) ← ----

Fork spring free length 454 mm (17.9 in) ← 449 mm (17.7

in)

Spring rate, STD K = 4.6 N/mm (0.469 kg/

mm, 26.3 lb/in)

Optional spring Yes ← ----

Oil capacity 541 cm

18.3 US oz)

Oil grade Suspension oil "S1" ← ----

Inner tube outer diameter 48 mm (1.89 in) ← ----

Front fork top end 5 mm (0.20 in) ← ----

Rear suspension: USA, CDN EUROPE, AUS, NZ, ZA

Shock absorber travel 131.5 mm (5.18 in) ← ----

Spring free length Approx.275 mm (10.83

in)

Fitting length*

I.D. mark (Pink/1) 266 mm (10.47 in) 263 mm (10.35 in) ----

I.D. mark (Pink/2) 272 mm (10.71 in) 269 mm (10.59 in) ----

I.D. mark (Pink/3) 263.5 mm (10.37 in) 260.5 mm (10.26 in) ----

(19.0 lmp oz,

← ----

531 cm3 (18.7 lmp oz,

18.0 US oz)

← ----

----

2-8

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