front wheel YAMAHA WR 250F 2004 Owners Manual

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS..................................... 4-1
EXHAUST PIPE AND
SILENCER.................................. 4-7
RADIATOR............................... 4-13
CARBURETOR........................ 4-21
CAMSHAFTS........................... 4-51
CYLINDER HEAD.................... 4-73
VALVES AND VALVE
SPRINGS.................................. 4-81
CYLINDER AND PISTON...... 4-101
CLUTCH................................. 4-117
OIL FILTER ELEMENT,
WATER PUMP AND RIGHT
CRANKCASE COVER........... 4-135
BALANCER............................ 4-151
OIL PUMP.............................. 4-159
KICK SHAFT AND
SHIFT SHAFT........................ 4-169
AC MAGNETO AND STARTER
CLUTCH................................. 4-185
ENGINE REMOVAL............... 4-207
CRANKCASE AND
CRANKSHAFT....................... 4-221
TRANSMISSION, SHIFT CAM
AND SHIFT FORK................. 4-245
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR
WHEEL....................................... 5-1
FRONT BRAKE AND
REAR BRAKE.......................... 5-23
FRONT FORK.......................... 5-61
HANDLEBAR........................... 5-91
STEERING............................. 5-103
SWINGARM........................... 5-119
REAR SHOCK ABSORBER.. 5-139
CHAPITRE 4
MOTEUR
SELLE, RESERVOIR DE
CARBURANT ET CACHES
LATERAUX..................................... 4-2
TUYAU D’ECHAPPEMENT ET
SILENCIEUX................................... 4-8
RADIATEUR................................. 4-14
CARBURATEUR.......................... 4-22
ARBRES A CAMES...................... 4-52
CULASSE....................................... 4-74
SOUPAPES ET RESSORTS DE
SOUPAPE....................................... 4-82
CYLINDRE ET PISTON............ 4-102
EMBRAYAGE............................. 4-118
ELEMENT DE FILTRE A
HUILE, POMPE A EAU ET
DEMI-CARTER DROIT............ 4-136
BALANCIER............................... 4-152
POMPE A HUILE....................... 4-160
ARBRE DE KICK ET
ARBRE DE SELECTEUR.......... 4-170
MAGNETO CA ET
ROCHET DE DEMARRAGE ... 4-186
DEPOSE DU MOTEUR.............. 4-208
CARTER ET VILEBREQUIN... 4-222
BOITE A VITESSES,
TAMBOUR ET FOURCHETTES
DE SELECTION.......................... 4-246
CHAPITRE 5
PARTIE CYCLE
ROUE AVANT ET ROUE
ARRIERE......................................... 5-2
FREIN AVANT ET FREIN
ARRIERE....................................... 5-24
FOURCHE AVANT...................... 5-62
GUIDON......................................... 5-92
DIRECTION................................ 5-104
BRAS OSCILLANT.................... 5-120
AMORTISSEUR ARRIERE...... 5-140

1 - 45
GEN
INFO
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
Rear Installation of rear
shock absorberRear shock absorber to frame
Rear 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
Rear Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Fuel system Fuel tank to fuel cock
Lubrication system Tightening of oil hose clamp
NOTE:Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” sec-
tion in the CHAPTER 2.
TORQUE-CHECK POINTS

1 - 51
GEN
INFO
EC1B0000
CLEANING AND
STORAGE
EC1B1000CLEANING
Frequent cleaning of your machine
will enhance its appearance, main-
tain 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 enter-
ing. 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.
CAUTION:
Excessive hose pressure may
cause water seepage and contami-
nation 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 sur-
faces with warm water and a
mild detergent. Use an old tooth-
brush to clean hard-to-reach
places.
5. Rinse the machine off immedi-
ately 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 uphol-
stery cleaner to keep the cover
pliable and glossy.
8. Automotive wax may be applied
to all painted or chromed sur-
faces. Avoid combination
cleaner-waxes, as they may con-
tain abrasives.
9. After completing the above, start
the engine and allow it to idle for
several minutes.
NETTOYAGE ET
RANGEMENT
NETTOYAGE
Un nettoyage fréquent de la machine
améliorera son aspect, maintiendra ses
bonnes performances et augmentera la
durée de service de bon nombre de ses
composants.
1. Avant de laver la moto, boucher la
sortie du pot d’échappement pour
éviter toute pénétration d’eau. Un
sachet en plastique retenu par un
élastique fera l’affaire.
2. Si le moteur est fortement encrassé,
appliquer un peu de dégraissant au
pinceau. Eviter tout contact avec la
chaîne, ses pignons et les axes de
roue.
3. Rincer la boue et le dégraissant au
tuyau d’arrosage, en utilisant juste
la pression suffisante.
ATTENTION:
Une pression excessive risque de pro-
voquer des infiltrations d’eau dans les
roulements des roues, la fourche
avant, des freins et les joints de la
transmission. Noter que bien des notes
de réparation onéreuses ont résulté de
l’emploi abusif des vaporisateurs de
détergent à haute pression, tels que
ceux qui équipent les laveries automa-
tiques de voitures.
4. Après avoir chassé la majeure partie
de la boue, laver toutes les surfaces
avec de l’eau chaude et un détergent
neutre. Utiliser une vieille brosse à
dents pour atteindre les endroits dif-
ficiles d’accès.
5. Rincer immédiatement l’engin avec
de l’eau propre et sécher toutes les
surfaces avec un chiffon doux.
6. Immédiatement après le lavage, éli-
miner l’excès d’eau de la chaîne
avec des mouchoirs en papier et
lubrifier la chaîne pour éviter
qu’elle ne rouille.
7. Nettoyer la selle avec un produit
pour meubles rembourrés pour que
sa housse reste souple et brillante.
8. Un encaustique pour automobile
peut être appliqué sur toutes les sur-
faces peintes et chromées. Eviter les
liquides de nettoyage à encaustique,
car ils contiennent de l’abrasif.
9. Les opérations ci-dessus terminées,
lancer le moteur et le laisser tourner
pendant quelques minutes.
CLEANING AND STORAGE
NETTOYAGE ET RANGEMENT

GENERAL SPECIFICATIONS
2 - 3
SPEC
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
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI
Generator system AC magneto
Battery type YTX5L-BS
Battery voltage/capacity 12 V/4 AH
Specific gravity 1.320
Headlight type: Quartz bulb (halogen)
Bulb wattage × quantity:
Headlight 12 V 60/55 W × 1
Taillight 12 V 21/5 W × 1

MAINTENANCE SPECIFICATIONS
2 - 13
SPEC
Wheel: USA, CDN, ZA EUROPE, AUS, NZ
Front wheel type Spoke wheel←----
Rear wheel type Spoke wheel←----
Front rim size/material 21 × 1.60/Aluminum←----
Rear rim size/material 18 × 1.85/Aluminum 18 × 2.15/Aluminum ----
Rim runout limit:
Radial ---- ---- 2.0 mm
(0.08 in)
Lateral ---- ---- 2.0 mm
(0.08 in)
Drive chain:
Type/manufacturer DID520VM/DAIDO ----
Number of links 113 links + joint ----
Chain slack 40 ~ 50 mm (1.6 ~ 2.0 in) ----
Chain length (10 links) ---- 150.1 mm
(5.91 in)
Front disc brake:
Disc outside dia. × Thickness 250 × 3.0 mm (9.84 × 0.12 in)
250 × 2.5 mm
(9.84
× 0.10 in)
Pad thickness 4.4 mm (0.17 in) 1.0 mm
(0.04 in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 27.0 mm (1.063 in) × 2 ----
Brake fluid type DOT #4 ----
Rear disc brake:
Disc outside dia. × Thickness 245 × 4.0 mm (9.65 × 0.16 in)
245 × 3.5 mm
(9.65
× 0.14 in)
Deflection limit ---- 0.15 mm
(0.006 in)
Pad thickness 6.4 mm (0.25 in) 1.0 mm
(0.04 in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 25.4 mm (1.000 in) × 1 ----
Brake fluid type DOT #4 ----
Brake lever and brake pedal:
Brake lever position 95 mm (3.74 in) ----
Brake pedal height
(vertical height above footrest top)5 mm (0.20 in) ----
Clutch lever free play (lever end) 8 ~ 13 mm (0.31 ~ 0.51 in) ----
Throttle grip free play 3 ~ 5 mm (0.12 ~ 0.20 in) ----Item Standard Limit

MAINTENANCE SPECIFICATIONS
2 - 14
SPEC
NOTE:
1. First, tighten the steering nut approximately 38 Nm (3.8 m  kg, 27 ft  lb) by using the steering
nut wrench, then loosen the steering nut one turn.
2. Retighten the steering nut 7 Nm (0.7 m  kg, 5.1 ft  lb). Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Upper bracket and outer tube M8 × 1.25 4 23 2.3 17
Lower bracket and outer tube M8 × 1.25 4 20 2.0 14
Upper bracket and steering stem M24 × 1.0 1 145 14.5 105
Handlebar upper holder and upper bracket M8 × 1.25 4 28 2.8 20
Steering stem and steering ring nut M28 × 1.0 1 Refer to NOTE.
Front fork and front fork cap bolt M48 × 1.0 2 30 3.0 22
Front fork and base valve M30 × 1.0 2 55 5.5 40
Front fork cap bolt and damper rod M12 × 1.25 2 29 2.9 21
Front fork bleed screw and front fork cap bolt M5 × 0.8 2 1 0.1 0.7
Front fork and front fork protector M6 × 1.0 6 10 1.0 7.2
Front fork and brake hose holder M6 × 1.0 2 10 1.0 7.2
Front fork and brake hose cover (M8) M8 × 1.25 1 16 1.6 11
(M6) M6 × 1.0 1 7 0.7 5.1
Throttle grip cap M5 × 0.8 2 4 0.4 2.9
Front brake master cylinder M6 × 1.0 2 9 0.9 6.5
Brake lever mounting bolt M6 × 1.0 1 6 0.6 4.3
Brake lever mounting nut M6 × 1.0 1 6 0.6 4.3
Brake lever position locknut M6 × 1.0 1 5 0.5 3.6
Front brake hose guide M5 × 0.8 2 4 0.4 2.9
Clutch lever holder M5 × 0.8 2 4 0.4 2.9
Clutch lever mounting nut M6 × 1.0 1 4 0.4 2.9
Hot starter lever holder M5 × 0.8 2 4 0.4 2.9
Hot starter lever mounting nut M5 × 0.8 1 2 0.2 1.4
Front brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
Front brake hose union bolt M10 × 1.25 2 30 3.0 22
Front brake caliper M8 × 1.25 2 23 2.3 17
Pad pin plug M10 × 1.0 2 3 0.3 2.2
Front brake caliper and pad pin M10 × 1.0 1 18 1.8 13
Rear brake caliper and pad pin M10 × 1.0 1 18 1.8 13
Brake caliper and bleed screw M8 × 1.25 2 6 0.6 4.3
Front wheel axle and axle nut M16 × 1.5 1 105 10.5 75
Front wheel axle holder M8 × 1.25 4 23 2.3 17
Front brake disc M6 × 1.0 6 12 1.2 8.7
Rear brake disc M6 × 1.0 6 14 1.4 10
Brake pedal M8 × 1.25 1 26 2.6 19
Rear brake master cylinder M6 × 1.0 2 11 1.1 8.0
Rear brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
Rear brake hose union bolt M10 × 1.25 2 30 3.0 22
Rear wheel axle and axle nut M20 × 1.5 1 125 12.5 90

MAINTENANCE SPECIFICATIONS
2 - 15
SPEC
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Nipple (spoke)—72 3 0.3 2.2
Rear wheel sprocket M8 × 1.25 6 50 5.0 36
Rear brake disc cover M6 × 1.0 2 7 0.7 5.1
Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 16 1.6 11
Engine mounting:
Engine and engine bracket (front) M10 × 1.25 1 69 6.9 50
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Engine bracket and frame M8 × 1.25 6 34 3.4 24
Engine and engine bracket (upper) M10 × 1.25 1 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
Left engine guard M8 × 1.25 2 23 2.3 17
Right engine guard M8 × 1.25 2 23 2.3 17
Regulator bracket and frame M6 × 1.0 2 7 0.7 5.1
Regulator M6 × 1.0 2 7 0.7 5.1
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 80 8.0 58
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame (upper) M8 × 1.25 1 32 3.2 23
Rear frame (lower) M8 × 1.25 2 29 2.9 21
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 19 1.9 13
Lower drive chain tensioner M8 × 1.25 1 20 2.0 14
Drive chain support M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank M6 × 1.0 2 10 1.0 7.2
Fuel cock M6 × 1.0 2 7 0.7 5.1
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Hooking screw (fitting band) and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 6 6 0.6 4.3
Air scoop and radiator guard (lower) M6 × 1.0 2 6 0.6 4.3
Front fender M6 × 1.0 4 7 0.7 5.1
Rear fender (front) M6 × 1.0 2 7 0.7 5.1
Rear fender (rear) M6 × 1.0 2 11 1.1 8.0
Side cover M6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17
Trip meter M6 × 1.0 2 7 0.7 5.1
Meter cable holder and front fork protector M5 × 0.8 2 4 0.4 2.9

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
*marked: For USAFRONT FORKS
Inspect and adjust
Replace oilSuspension oil “01”
Replace oil seal
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubeLithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
(After
rain
ride)Molybdenum disulfide
grease
Retighten
DRIVE CHAIN GUIDE AND ROLLERS
Inspect
DRIVE CHAIN STOPPER
Inspect
SWINGARMMolybdenum disulfide
grease
Inspect, lube and retighten
RELAY ARM, CONNECTING ROD Molybdenum disulfide
grease
Inspect, lube and retighten
SIDESTAND
LubricateLithium base grease
STEERING HEAD
Inspect free play and retighten
Clean and lubeLithium base grease
Replace bearing
TIRE, WHEELS
Inspect air pressure, wheel run-out, tire
wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
LubricateLithium base grease
THROTTLE, CONTROL CABLE Yamaha cable lube or SAE
10W-30 motor oil
Inspect dirt and wear on the
throttle cable on the
carburetor side. Check routing and connection
Lubricate
Inspect and clean (throttle cable)
HOT STARTER, CLUTCH LEVER
Inspect free play
BATTERY
Check terminal for looseness and
corrosionItemAfter
break-inEvery
race
Every third
(or
500 km)Every fifth
(or
1,000 km)As
requiredRemarks

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