Yamaha YZ450FT user guide
LIT-11626-18-44
YZ450FT
5XD-28199-11
OWNER’S SERVICE MANUAL
EC010000
YZ450FT
OWNER’S SERVICE MANUAL
©2004 by Yamaha Motor Corporation, U.S.A.
1st Edition, June 2004
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-11626-18-44
EC020000
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.
OTE:
As improvements are made on this model,
some data in this manual may become outdated. If you have any questions, please consult your Yamaha dealer.
WARNING
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 NOTICE
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.
SAFETY INFORMATION
1. 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.
2. THIS MACHINE IS DESIGNED TO BE
RIDDEN BY THE OPERATOR ONLY.
Do not carry passengers on this
machine.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
EC050000
TO THE NEW OWNER
This manual will provide you with a good basic
understanding of features, operation, and
basic maintenance and inspection items of this
machine. Please read this manual carefully
and completely before operating your new
machine. If you have any questions regarding
the operation or maintenance of your machine,
please consult your Yamaha dealer.
OTE:
This manual should be considered a permanent part of this machine and should remain
with it even if the machine is subsequently
sold.
EC060000
NOTICE
Some data in this manual may become outdated due to improvements made to this
model in the future. If there is any question
you have regarding this manual or your
machine, please consult your Yamaha
dealer.
EC070001
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.
EC080000
WARNING
CAUTION:
HOW TO USE
THIS MANUAL
EC081000
PARTICULARLY IMPORTANT
INFORMATION
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 damage to the
machine.
NOTE:
A NOTE provides key information to make procedures easier or clearer.
EC082000
FINDING THE REQUIRED PAGE
1. This manual consists of seven chapters;
“General Information”, “Specifications”,
“Regular inspection and adjustments”,
“Engine”, “Chassis”, “Electrical” and “Tun-
ing”.
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.
EC083000
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.
EC084002
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. Extent of removal 5 is provided in the job instruction chart to save the trouble of an unneces-
sary removal job.
6. For jobs requiring more information, the step-by-step format supplements 6 are given in addi-
tion to the exploded diagram and job instruction chart.
12
ILLUSTRATED SYMBOLS
GEN
INFO
34
SPEC
INSP
ADJ
56
CHAS
78
ENG
–+
ELEC
TUN
90
(Refer to the illustration)
Illustrated symbols 1 to 7 are designed as
thumb tabs to indicate the chapter’s number
and content.
General information
1
Specifications
2
Regular inspection and adjustments
3
Engine
4
Chassis
5
Electrical
6
Tuning
7
Illustrated symbols 8 to D are used to identify
the specifications appearing in the text.
With engine mounted
8
Special tool
9
Filling fluid
0
Lubricant
A
Tightening
B
Specified value, Service limit
C
Resistance (Ω), Voltage (V), Electric current (A)
D
AB
T
.
R
.
CD
EF
E
GH
B
IJ
M
M
New
Illustrated symbols E to H in the exploded
diagrams indicate grade of lubricant and location of lubrication point.
Apply engine oil
E
Apply molybdenum disulfide oil
F
Apply lightweight lithium-soap base grease
G
Apply molybdenum disulfide grease
H
Illustrated symbols I to J in the exploded
diagrams indicate where to apply a locking
agent and where to install new parts.
®
Apply locking agent (LOCTITE
I
Use new one
J
)
EC090000
INDEX
GENERAL
INFORMATION
SPECIFICATIONS
REGULAR
GEN
INFO
SPEC
1
2
INSPECTION AND
ADJUSTMENTS
ENGINE
CHASSIS
ELECTRICAL
TUNING
INSP
ADJ
ENG
CHAS
– +
ELEC
TUN
3
4
5
6
7
EC0A0000
CONTENTS
CHAPTER 1
GENERAL INFORMATION
DESCRIPTION
MACHINE IDENTIFICATION
IMPORTANT INFORMATION
CHECKING OF CONNECTION
SPECIAL TOOLS
CONTROL FUNCTIONS
FUEL
STARTING AND BREAK-IN
TORQUE-CHECK POINTS
CLEANING AND STORAGE
........................................................1-13
...........................................1-1
.....................1-2
....................1-3
.................1-6
......................................1-7
..........................1-10
....................1-14
......................1-18
...................1-19
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
GENERAL TORQUE
SPECIFICATIONS
DEFINITION OF UNITS
LUBRICATION DIAGRAMS
CABLE ROUTING DIAGRAM
...................................2-18
...........................2-18
...................2-1
....................2-19
.................2-21
..........2-4
CHAPTER 3
REGULAR INSPECTION
AND ADJUSTMENTS
MAINTENANCE INTERVALS
PRE-OPERATION INSPECTION
AND MAINTENANCE
ENGINE
CHASSIS
ELECTRICAL
......................................................3-5
.................................................3-24
...........................................3-46
................................3-4
...................3-1
CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS
EXHAUST PIPE AND SILENCER
RADIATOR
CARBURETOR
CAMSHAFTS
CYLINDER HEAD
VALVES AND VALVE SPRINGS
CYLINDER AND PISTON
CLUTCH
OIL FILTER, WATER PUMP
AND CRANKCASE COVER (RIGHT)
BALANCER
OIL PUMP
KICK AXLE AND SHIFT SHAFT
CDI MAGNETO
ENGINE REMOVAL
CRANKCASE AND CRANKSHAFT
TRANSMISSION, SHIFT CAM
AND SHIFT FORK
................................................4-5
...........................................4-21
...................................................4-48
.............................................4-62
................................................4-65
..................................4-1
.............4-3
..........................................4-8
....................................4-29
............4-33
........................4-42
.............4-69
........................................4-76
.................................4-80
...................................4-94
.....4-55
........4-85
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
FRONT BRAKE AND REAR BRAKE
FRONT FORK
HANDLEBAR
STEERING
SWINGARM
REAR SHOCK ABSORBER
..........................................5-26
...........................................5-42
...............................................5-48
.............................................5-53
....................5-61
.......5-1
.....5-10
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM
MAP-CONTROLLED CDI UNIT
IGNITION SYSTEM
TPS (THROTTLE POSITION SENSOR)
SYSTEM
.....................................................6-7
...........................6-1
.................6-2
....................................6-3
CHAPTER 7
TUNING
ENGINE
CHASSIS
......................................................7-1
.................................................7-11
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
Clutch lever
1
Hot starter lever
2
Front brake lever
3
Throttle grip
4
Radiator cap
5
Fuel tank cap
6
“ENGINE STOP” button
7
Kick starter
8
Fuel tank
9
Radiator
0
Coolant drain bolt
A
Rear brake pedal
B
Valve joint
C
Fuel cock
D
Cold starter knob
E
Drive chain
F
Air cleaner
G
Shift pedal
H
Oil dipstick
I
Front fork
J
GEN
DESCRIPTION
OTE:
• The machine you have purchased may differ
slightly from those shown in the following.
• Designs and specifications are subject to
change without notice.
INFO
1
1 - 1
MACHINE IDENTIFICATION
EC120001
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.
EC121001
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1 is
stamped on the right of the steering head pipe.
GEN
INFO
EC123001
ENGINE SERIAL NUMBER
The engine serial number 1 is stamped into
the elevated part of the right-side of the
engine.
EC124000
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 - 2
IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131010
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 as follows.
• Silencer exhaust port
• Side cover air intake port
• Water pump housing hole at the bottom
• Drain hole on the cylinder head (right
side)
GEN
INFO
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.
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.
1 - 3
IMPORTANT INFORMATION
EC132000
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.
EC133000
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 Orings must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.
GEN
INFO
EC134000
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.
EC135001
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 light-weight
lithium base grease to the seal lip(s). Oil
the bearings liberally when installing.
CAUTION:
Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.
1 - 4
IMPORTANT INFORMATION
EC136000
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.
Shaft
4
GEN
INFO
1 - 5
CHECKING OF CONNECTION
EC1C0001
CHECKING OF CONNECTION
Dealing with stains, rust, moisture, etc. on the
connector.
1. Disconnect:
• Connector
2. Dry each terminal with an air blower.
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.
GEN
INFO
6. Connect:
• Connector
OTE:
The two connectors “click” together.
7. Check for continuity with a tester.
OTE:
• 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 revitalizer
available on the market.
• Use the tester on the connector as shown.
1 - 6
GEN
SPECIAL TOOLS
EC140001
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.
OTE:
• For U.S.A. and Canada, use part number starting with “YM-”, “YU-” or “ACC-”.
• For others, use part number starting with “90890-”.
Part number Tool name/How to use Illustration
YU-1135-A, 90890-01135 Crankcase separating tool
These tool is used to remove the crankshaft from
either case.
YU-1235, 90890-01235 Rotor holding tool
YU-1135-A 90890-01135
YU-1235 90890-01235
INFO
This tool is used when loosening or tightening the flywheel magneto securing nut.
YU-3097, 90890-01252
YU-1256
YU-90050, 90890-01274
YU-90050, 90890-01275
YU-91044, 90890-04081
YU-90063, 90890-01278
YU-1304, 90890-01304 Piston pin puller
YU-24460-01, 90890-01325
YU-33984, 90890-01352
YM-1189, 90890-01189 Flywheel puller
Dial gauge and stand
Stand
These tools are used to check each part for runout or
bend.
Crankshaft installing tool
Crankshaft installing pot
Crankshaft installing bolt
Spacer (crankshaft installer)
Adapter (M12)
These tools are used to install the crankshaft.
This tool is used to remove the piston pin.
Radiator cap tester
Adapter
These tools are used for checking the cooling system.
YU-3097
YU-1256
YU-90050
YU-90063
YU-91044
YU-1304 90890-01304
YU-24460-01
YU-33984
YM-1189 90890-01189
90890-01252
90890-01274
90890-01275
90890-01278
90890-04081
90890-01325
90890-01352
This tool is used to remove the flywheel magneto.
1 - 7
SPECIAL TOOLS
Part number Tool name/How to use Illustration
YU-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.
YM-01442, 90890-01442 Fork seal driver
This tool is used when install the fork oil seal.
YM-01500, 90890-01500 Cap bolt wrench
This tool is used to loosen or tighten the base valve.
YM-01501, 90890-01501 Cap bolt ring wrench
YU-33975 90890-01403
YM-01442 90890-01442
YM-01500 90890-01500
YM-01501 90890-01501
GEN
INFO
This tool is used to loosen or tighten the damper
assembly.
YU-3112-C, 90890-03112 Pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.
YM-33277-A, 90890-03141 Timing light
This tool is necessary for checking ignition timing.
YM-4019, 90890-04019 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.
YM-4116, 90890-04116
YM-4097, 90890-04097
Valve guide remover
Intake 4.5 mm (0.18 in)
Exhaust 5.0 mm (0.20 in)
YU-3112-C 90890-03112
YM-33277-A 90890-03141
YM-4019 90890-04019
YM-91042 90890-04086
YM-4116
YM-4097
90890-04116
90890-04097
This tool is needed to remove and install the valve
guide.
1 - 8
SPECIAL TOOLS
Part number Tool name/How to use Illustration
YM-4117, 90890-04117
YM-4098, 90890-04098
YM-4118, 90890-04118
YM-4099, 90890-04099
YM-34487
90890-06754
ACC-QUICK-GS-KT
90890-85505
Valve guide installer
Intake
Exhaust
This tool is needed to install the valve guide.
Valve guide reamer
Intake 4.5 mm (0.18 in)
Exhaust 5.0 mm (0.20 in)
This tool is needed to rebore the new valve guide.
Dynamic spark tester
Ignition checker
This instrument is necessary for checking the ignition
system components.
Quick gasket
YAMAHA Bond No. 1215
YM-4117
YM-4098
YM-4118
YM-4099
YM-34487 90890-06754
ACC-QUICK-GS-KT 90890-85505
GEN
INFO
90890-04117
90890-04098
90890-04118
90890-04099
This sealant (Bond) is used for crankcase mating surface, etc.
1 - 9
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
EC151000
“ENGINE STOP” BUTTON
The “ENGINE STOP” button 1 is located on
the left handlebar. Continue pushing the
“ENGINE STOP” button till the engine comes
to a stop.
EC152000
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.
GEN
INFO
1
EC153000
SHIFT PEDAL
The gear ratios of the constant-mesh 4 speed
transmission are ideally spaced. The gears
can be shifted by using the shift pedal 1 on
the left side of the engine.
EC154000
KICK STARTER
Rotate the kick starter 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 kick starter so the engine can be
started in any gear if the clutch is disengaged.
In normal practices, however, shift to neutral
before starting.
EC155001
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.
1 - 10
CONTROL FUNCTIONS
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to activate the front brake.
EC157000
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.
GEN
INFO
EC158001
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor while filtering 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.
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.
1 - 11
CONTROL FUNCTIONS
EC15R001
DETACHABLE SIDESTAND
This sidestand 1 is used to support only the
machine when standing or transporting it.
WARNING
• Never apply additional force to the sidestand.
• Remove this sidestand before starting
out.
EC15F000
VALVE JOINT
This valve joint 1 prevents fuel from flowing
out and is installed to the fuel tank breather
hose.
CAUTION:
In this installation, make sure the arrow
faces the fuel tank and also downward.
GEN
INFO
1
SPARK PLUG WRENCH
This spark plug wrench 1 is used to remove
and install the spark plug.
1
NIPPLE WRENCH
This nipple wrench 1 is used to tighten the
spoke.
1 - 12
GEN
FUEL
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.
CAUTION:
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.
OTE:
If knocking or pinging occurs, use a different
brand of gasoline or higher octane grade.
INFO
WARNING
• 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.
1 - 13
STARTING AND BREAK-IN
STARTING AND BREAK-IN
WARNING
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.
CAUTION:
• 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 kick starter 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.
GEN
INFO
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 kick starter.
WARNING
Do not open the throttle while kicking the
kick starter. Otherwise, the kick starter may
kick back.
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STARTING AND BREAK-IN
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.
OTE:
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.
CAUTION:
Do not warm up the engine for extended
periods of time.
GEN
INFO
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