2004 YAMAHA WR 250F front wheel

3 - 16
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.P.3-21 ~ 29
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-35
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-39 ~ 47
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-29 ~ 31
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-31 ~ 33
Brakes Check the play of front brake and effect of front and rear brake. P.3-65 ~ 77
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-79 ~ 83
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-99 ~ 101
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-101 ~ 103
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-85 ~ 97
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down.—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-7 ~ 11
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-77
Lubrication Check for smooth operation. Lubricate if necessary. P.3-105
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-45
Lead connectorsCheck that the AC magneto, CDI unit, and ignition coil are
connected tightly.P.1-9
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 42

3 - 73
INSP
ADJ
4. Check:
Brake lever operation
A softy or spongy feeling
→
Bleed brake system.
Refer to “BRAKE SYSTEM
AIR BLEEDING” section.
REAR BRAKE PAD INSPECTION
AND REPLACEMENT
1. Inspect:
Brake pad thickness
a
Out of specification
→
Replace as a set.
Brake pad thickness:
6.4 mm (0.25 in)
:
1.0 mm (0.04 in)
2. Replace:
Brake pad
Brake pad replacement steps:
Remove the protector
1 and
pad pin plug
2.
Loosen the pad pin
3.
Remove the rear wheel
4 and
brake caliper
5.
Refer to “FRONT WHEEL AND
REAR WHEEL” section in the
CHAPTER 5.
Remove the pad pin
6 and
brake pads
7.
Connect the transparent hose
8 to the bleed screw
9 and
place the suitable container
under its end.
Loosen the bleed screw and
push the brake caliper piston in.
CAUTION:
Do not reuse the drained brake
fluid.
Tighten the bleed screw.
T R..
Bleed screw:
6 Nm
(0.6 m  kg, 4.3 ft  lb)
4. Contrôler:
Fonctionnement du levier de frein
Sensation de mollesse → Purger
le circuit de freinage.
Se reporter à la section “PURGE
DE L’AIR DU SYSTEME DE
FREINAGE”.
CONTROLE ET CHANGEMENT
DES PLAQUETTES DE FREIN
ARRIERE
1. Contôler:
Epaisseur de plaquette de frein a
Hors spécification → Remplacer
la paire.
Epaisseur de plaquette de
frein:
6,4 mm (0,25 in)
:
1,0 mm (0,04 in)
2. Changer:
Plaquette de frein
Etapes de changement de plaquette
de frein:
Déposer la protection 1 et le bou-
chon de la goupille de plaquette 2.
Desserrer la goupille de plaquette
3.
Déposer la roue arrière 4 et
l’étrier de frein 5.
Se reporter à la section “ROUE
AVANT ET ROUE ARRIERE” au
CHAPITRE 5.
Déposer la goupille de plaquette 6
et les plaquettes de frein 7.
Connecter le tuyau transparent 8 à
la vis de purge 9 et placer un réci-
pient approprié sous son extrémité.
Desserrer la vis de purge et y
enfoncer le piston d’étrier de frein.
ATTENTION:
Ne pas réutiliser le liquide de frein
purgé.
Serrer la vis de purge.
T R..
Vis de purge:
6 Nm
(0,6 m  kg, 4,3 ft  lb)
CHASSIS
PARTIE CYCLE

3 - 75
INSP
ADJ
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID
LEVEL INSPECTION” section.
4. Check:
Brake pedal operation
A softy or spongy feeling
→
Bleed brake system.
Refer to “BRAKE SYSTEM
AIR BLEEDING” section. Install the brake pad
0 and pad
pin
A.
NOTE:Install the brake pads with their
projections
a into the brake
caliper recesses
b.
Temporarily tighten the pad pin
at this point.
Install the brake caliper
B and
rear wheel
C.
Refer to “FRONT WHEEL AND
REAR WHEEL” section in the
CHAPTER 5.
Tighten the pad pin
D.
T R..
Pad pin:
18 Nm
(1.8 m  kg, 13 ft  lb)
Install the pad pin plug
E and
protector
F.
T R..
Pad pin plug:
3 Nm
(0.3 m  kg, 2.2 ft  lb)
Bolt (protector):
7 Nm
(0.7 m  kg, 5.1 ft  lb)
EC36b000REAR BRAKE PAD INSULATOR
INSPECTION
1. Remove:
Brake pad
Refer to “REAR BRAKE PAD
INSPECTION AND
REPLACEMENT” section.
2. Inspect:
Rear brake pad insulator
1
Damage
→ Replace.
3. Contôler:
Niveau du liquide de frein
Se reporter à la section “CON-
TROLE DU NIVEAU DU
LIQUIDE DE FREIN”.
4. Contrôler:
Fonctionnement de la pédale de
frein
Sensation de mollesse → Purger
le circuit de freinage.
Se reporter à la section “PURGE
DE L’AIR DU SYSTEME DE
FREINAGE”. Installer la plaquette de frein 0 et
la goupille de plaquette A.
N.B.:
Installer les plaquettes de frein en
ajustant leurs saillies a dans les
encoches de l’étrier de frein b.
A ce stade, serrer provisoirement la
goupille de plaquette.
Monter l’étrier de frein B et la
roue arrière C.
Se reporter à la section “ROUE
AVANT ET ROUE ARRIERE” au
CHAPITRE 5.
Serrer la goupille de plaquette D.
T R..
Goupille de plaquette:
18 Nm
(1,8 m  kg, 13 ft  lb)
Installer la bouchon de la goupille
de plaquette E et la protection F.
T R..
Bouchon de la goupille de
plaquette:
3 Nm
(0,3 m  kg, 2,2 ft  lb)
Boulon (protection):
7 Nm
(0,7 m  kg, 5,1 ft  lb)
CONTROLE DE L’ISOLANT DE LA
PLAQUETTE DE FREIN ARRIERE
1. Déposer:
Plaquette de frein
Se reporter à la section “CON-
TROLE ET CHANGEMENT
DES PLAQUETTES DE FREIN
ARRIERE”.
2. Contrôler:
Isolant de la plaquette de frein
arrière 1
Endommagement → Remplacer.
CHASSIS
PARTIE CYCLE

3 - 77
INSP
ADJ
BRAKE FLUID LEVEL
INSPECTION
1. Place the brake master cylinder
so that its top is in a horizontal
position.
2. Inspect:
Brake fluid level
Fluid at lower level
→ Fill up.
aLower level
ÈFront
ÉRear
WARNING
Use only designated quality
brake fluid to avoid poor brake
performance.
Refill with same type and brand
of brake fluid; mixing fluids
could result in poor brake per-
formance.
Be sure that water or other con-
taminants do not enter master
cylinder when refilling.
Clean up spilled fluid immedi-
ately to avoid erosion of painted
surfaces or plastic parts.
Recommended brake
fluid:
DOT #4
ÈÉ
SPROCKETS INSPECTION
1. Inspect:
Sprocket teeth
a
Excessive wear
→ Replace.
NOTE:Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CONTROLE DU NIVEAU DU
LIQUIDE DE FREIN
1. Placer le maître-cylindre pour que
son extrémité soit en position hori-
zontale.
2. Contôler:
Niveau de liquide de frein
Liquide au niveau inférieur →
Remettre à niveau.
a
Niveau inférieur
È
Avant
É
Arrière
AVERTISSEMENT
Utiliser uniquement le liquide
recommandé pour éviter une perte
de puissance de freinage.
Ne rajouter que du liquide de même
marque et de même qualité. Le
mélange de différents liquides peut
se traduire par une perte de puis-
sance de freinage.
Ne pas laisser entrer d’eau ou
d’autres corps étrangers dans le
maître-cylindre lors du remplissage.
Essuyer immédiatement tout liquide
renversé pour éviter d’endommager
les surfaces peintes ou les pièces en
matière plastique.
Liquide de frein
recommandé:
DOT n°4
CONTROLE DES PIGNONS
1. Contrôler:
Dents de pignon
a
Usure excessive → Remplacer.
N.B.:
Remplacer le pignon d’entraînement, la
couronne arrière et la chaîne de transmis-
sion en un ensemble.
CHASSIS
PARTIE CYCLE

3 - 85
INSP
ADJ
EC36C000FRONT FORK INSPECTION
1. Inspect:
Front fork smooth action
Operate the front brake and
stroke the front fork.
Unsmooth action/oil leakage
→ Repair or replace.
EC36D001FRONT FORK OIL SEAL AND
DUST SEAL CLEANING
1. Remove:
Protector
Dust seal
1
NOTE:Use a thin screw driver, and be care-
ful not to damage the inner fork tube
and dust seal.
2. Clean:
Dust seal
a
Oil seal
b
NOTE:Clean the dust seal and oil seal
after every run.
Apply the lithium soap base grease
on the inner tube.
FRONT FORK INTERNAL
PRESSURE RELIEVING
NOTE:If the front fork initial movement feels
stiff during a run, relieve the front fork
internal pressure.
1. Elevate the front wheel by plac-
ing a suitable stand under the
engine.
2. Remove the air bleed screw
1
and release the internal pressure
from the front fork.
3. Install:
Air bleed screw
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
CONTROLE DE LA FOURCHE
AVANT
1. Contrôler:
Action régulière de la fourche
avant
Actionner le frein avant et donner
un coup à la fourche avant.
Action irrégulière/fuites d’huile
→ Réparer ou remplacer.
NETTOYAGE DE BAGUE
D’ETANCHEITE ET DE JOINT
ANTIPOUSSIERE DE FOURCHE
AVANT
1. Déposer:
Protection
Joint antipoussière 1
N.B.:
Utiliser un petit tournevis et faire atten-
tion à ne pas endommager le fourreau de
fourche interne ni le cache-poussière.
2. Nettoyer:
Joint antipoussière a
Bague d’étanchéité b
N.B.:
Nettoyer le joint antipoussière et la
bague d’étanchéité après chaque
course.
Appliquer la graisse à base de savon
au lithium sur le tube interne.
PURGE DE L’AIR DE LA
FOURCHE AVANT
N.B.:
Si le mouvement initial de la fourche
avant montre une certaine raideur à l’uti-
lisation, purger l’air de la fourche avant.
1. Surélever la fourche avant en pla-
çant un support adéquat sous le
moteur.
2. Enlever la vis de purge d’air 1
pour purger la fourche avant.
3. Monter:
Vis de purge d’air
T R..1 Nm (0,1 m · kg, 0,7 ft · lb)
CHASSIS
PARTIE CYCLE

3 - 101
INSP
ADJ
2. Inspect:
Bearing free play
Exist play
→ Replace.
EC36U013STEERING HEAD INSPECTION
AND ADJUSTMENT
1. Elevate the front wheel by plac-
ing a suitable stand under the
engine.
2. Check:
Steering stem
Grasp the bottom of the forks
and gently rock the fork
assembly back and forth.
Free play
→ Adjust steering
head.
3. Check:
Steering smooth action
Turn the handlebar lock to
lock.
Unsmooth action
→ Adjust
steering ring nut.
4. Adjust:
Steering ring nut
Steering ring nut adjustment
steps:
Remove the headlight.
Remove the handlebar and
handlebar upper bracket.
Loosen the steering ring nut
1
using the steering nut wrench
2.
Steering nut wrench:
YU-33975/90890-01403
Tighten the steering ring nut
3
using steering nut wrench
4.
NOTE:Set the torque wrench to the
steering nut wrench so that they
form a right angle.
Steering nut wrench:
YU-33975/90890-01403
T R..
Steering ring nut
(initial tightening):
38 Nm
(3.8 m  kg, 27 ft  lb)
2. Contrôler:
Jeu de roulement
Il y a du jeu → Remplacer.
CONTROLE ET REGLAGE DE LA
TETE DE FOURCHE
1. Soulever la roue avant en mettant
un support convenable sous le
moteur.
2. Contrôler:
Arbre de direction
Saisir la fourche par le bas et bas-
culer l’ensemble en avant et en
arrière.
Jeu → Régler la tête de fourche.
3. Contrôler:
Action régulière de la direction
Tourner le guidon à fond dans les
deux sens.
Action irrégulière → Régler
l’écrou annulaire de direction.
4. Régler:
Ecrou crénelé de direction
Etapes de réglage de l’écrou cré-
nelé de direction:
Retirer le phare.
Retirer le guidon et le support
supérieur.
Desserrer l’écrou crénelé de direc-
tion 1 en utilisant la clé à ergots
2.
Clé à ergots:
YU-33975/90890-01403
Serrer l’écrou crénelé de direction
3 en utilisant la clé 4.
N.B.:
Régler la clef dynamométrique à la
clé à ergots pour former un angle
droit.
Clé à ergots:
YU-33975/90890-01403
T R..
Ecrou crénelé de direction
(serrage initial):
38 Nm
(3,8 m  kg, 27 ft  lb)
CHASSIS
PARTIE CYCLE

5 - 1
CHASFRONT WHEEL AND REAR WHEEL
EC500000
CHASSIS
EC590000
FRONT WHEEL AND REAR WHEEL
EC598000FRONT WHEEL
Extent of removal:
1 Front wheel removal
2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
1 Trip meter cable 1
2 Brake hose cover 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Bolt (axle holder) 4 Only loosening.
5 Nut (front wheel axle) 1
6 Front wheel axle 1
7 Front wheel 1
8 Trip meter gear unit 1
9 Collar 1
10 Oil seal 1
11 Bearing 2 Refer to “REMOVAL POINTS”.
12 Brake disc 1
1
2
3
3

5 - 5
CHASFRONT WHEEL AND REAR WHEEL
EC598100REAR WHEEL
Extent of removal:
1 Rear wheel removal
2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Drive chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10 Brake disc 1
1
2
3
3