2000 YAMAHA YZ426F oil

6. GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline,
inhale excess gasoline vapors, or allow
any gasoline to get into your eyes, con-
tact a doctor immediately. If any gasoline
spills onto your skin or clothing, immedi-
ately wash skin areas with soap and
water, and change your clothes.
7. ONLY OPERATE THE MACHINE IN AN
AREA WITH ADEQUATE VENTILA-
TION.
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. Car-
bon 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 prop-
erly 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.

EC085001
ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols
1
to
7
are designed as
thumb tabs to indicate the chapter’s number
and content.
1
General information
2
Specifications
3
Regular inspection and adjustments
4
Engine
5
Chassis
6
Electrical
7
Tuning
Illustrated symbols
8
to
D
are used to identify
the specifications appearing in the text.
8
With engine mounted
9
Special tool
0
Filling fluid
A
Lubricant
B
Tightening
C
Specified value, Service limit
D
Resistance (
W
), Voltage (V), Electric current (A)
Illustrated symbols
E
to
I
in the exploded
diagrams indicate grade of lubricant and loca-
tion of lubrication point.
E
Apply gear oil
F
Apply engine oil
G
Apply molybdenum disulfide oil
H
Apply lightweight lithium-soap base grease
I
Apply molybdenum disulfide grease
Illustrated symbols
J to K in the exploded
diagrams indicate where to apply a locking
agent and where to install new parts.
JApply locking agent (LOCTITE®)
KUse new one 12
34
56
78
90
AB
CD
EFG
HI
JK
GEN
INFOSPEC
INSP
ADJENG
CHAS–+ELEC
TUN
T R..
GME
BM
New

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND
SIDE COVERS
.......................................... 4-1
EXHAUST PIPE AND SILENCER
............ 4-3
RADIATOR
................................................ 4-4
CARBURETOR
......................................... 4-7
CAMSHAFTS
.......................................... 4-17
CYLINDER HEAD
................................... 4-24
VALVES AND VALVE SPRINGS
........... 4-27
CYLINDER AND PISTON
....................... 4-35
CLUTCH
.................................................. 4-41
OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)
............. 4-47
BALANCER
............................................ 4-53
OIL PUMP
............................................... 4-56
KICK AXLE AND SHIFT SHAFT
............ 4-60
CDI MAGNETO
....................................... 4-67
ENGINE REMOVAL
................................ 4-71
CRANKCASE AND CRANKSHAFT
....... 4-76
TRANSMISSION, SHIFT CAM,
SHIFT FORK
........................................... 4-85
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
...... 5-1
FRONT BRAKE AND REAR BRAKE
..... 5-10
FRONT FORK
......................................... 5-27
HANDLEBAR
.......................................... 5-40
STEERING
.............................................. 5-45
SWINGARM
............................................ 5-50
REAR SHOCK ABSORBER
................... 5- 57

1 - 1
GEN
INFO

DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1
Clutch lever
2
Decompression lever
3
Front brake lever
4
Throttle grip
5
Radiator cap
6
Fuel tank cap
7
Oil filler plug/dipstick
8
“ENGINE STOP” button
9
Kick starter
0
Fuel tank
A
Radiator
B
Coolant drain bolt
C
Rear brake pedal
D
Valve joint
E
Fuel cock
F
Cold starter knob
G
Hot starter knob (red)
H
Drive chain
I
Air cleaner
J
Shift pedal
K
Front fork
NOTE:

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

1 - 3
GEN
INFO

IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131002
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Remove all dirt, mud, dust, and foreign
material before removal and disassem-
bly.
2. Use proper tools and cleaning equip-
ment. Refer to “SPECIAL TOOLS” sec-
tion.
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.
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.

1 - 4
GEN
INFO

IMPORTANT INFORMATION
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should
be replaced when an engine is over-
hauled. 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.
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 num-
bers 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.
EC136000
CIRCLIPS
1. All circlips should be inspected carefully
before reassembly. Always replace pis-
ton pin clips after one use. Replace dis-
torted circlips. When installing a circlip
1
, make sure that the sharp-edged cor-
ner
2
is positioned opposite to the thrust
3
it receives. See the sectional view.
4
Shaft

1 - 7
GEN
INFO
SPECIAL TOOLS
YM-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.YM-33975 90890-01403
YM-1423, 90890-01423 Damper rod holder
Use this tool to remove and install the damper rod.YM-1423 90890-01423
YM-01442, 90890-01442 Fork seal driver
This tool is used when install the fork oil seal.YM-01442 90890-01442
YU-03112, 90890-03112 Yamaha pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-03112 90890-03112
YU-8036-1
90890-03113Inductive tachometer
Engine tachometer
This tool is needed for observing engine rpm.YU-8036-1 90890-03113
YM-33277-A, 90890-03141 Timing light
This tool is necessary for checking ignition timing.YM-33277-A 90890-03141
YM-04019, 90890-04019
YM-04108, 90890-04108Valve spring compressor
Attachment
This tool needed to remove and install the valve
assemblies.YM-04019
YM-0410890890-04019
90890-04108
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-91042 90890-04086
YM-4116, 90890-04116
YM-4097, 90890-04097Valve guide remover
Intake (4.5 mm)
Exhaust (5.0 mm)
This tool is needed to remove and install the valve
guide.YM-4116
YM-409790890-04116
90890-04097
Part number Tool name/How to use Illustration

GEN
INFO
OUTILS SPECIAUX
OUTILS SPECIAUX
Les outils spéciaux appropriés sont indispensables pour pouvoir effectuer un assemblage et une mise au point
complets et précis. L’utilisation des outils spéciaux corrects permettra d’éviter les endommagements dus à
l’emploi d’outils impropres et aux techniques improvisées entraînées par ceux-ci. La forme et le numéro de
pièce des outils spéciaux diffèrent selon les pays. Voilà pourquoi il y a parfois deux versions d’un outil. La
liste suivante permet d’éviter toute erreur lors de la commande de pièces.
N.B.:
lPour les E.-U. et le Canada, utiliser les numéros de pièce qui commencent par “YM-” ou “YU-”.
lPour les autres pays utiliser les numéros de pièce qui commencent par “90890-”.
Numéros de pièce Nom et usage de l’outil Illustration
YU-01135-A, 90890-01135
YM-01305, 90890-01305Outil de séparation de carter
Boulon de séparation de carter
Ces outils permettent de séparer le carter et d’extraire le
vilebrequin d’un demi-carter.YU-01135-A
YM-0130590890-01135
90890-01305
YU-01235, 90890-01235 Outil de maintien de rotor
Cet outil est utilisé pour le desserrage ou le serrage du
boulon de fixation de volant magnétique.YU-01235 90890-01235
YU-03097, 90890-01252
YU-01256Comparateur et support
Support
Ces outils sont utilisés pour caler l’allumage.YU-03097
YU-0125690890-01252
YU-90050, 90890-01274
YU-90050, 90890-01275
YU-91044, 90890-04081
YU-90062, 90890-01277Outil de pose du vilebrequin
Pot
Boulon
Entretoise
Adaptateur
Ces outils sont utilisé pour la montage du vilebrequin.YU-90050
YU-90062
YU-9104490890-01274
90890-01275
90890-01277
90890-04081
YU-01304, 90890-01304 Extracteur d’axe de piston
Cet outil est utilisé pour extraire les axes de piston.YU-01304 90890-01304
YU-24460-1, 90890-01325
YU-33984, 90890-01352Appareil de contrôle de bouchon de radiateur
Adaptateur
Ces outils sont utilisés pour le contrôle du système de
refroidissement.YU-24460-01
YU-3398490890-01325
90890-01352
YM-01189, 90890-01189 Extracteur du volant
Cet outil doit être utilisé pour la dépose du volant magnéti-
que.YM-01189 90890-01189
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