CHAPTER 4
TUNING
ENGINE...................................... 4-1
CHASSIS.................................. 4-21
CHAPTER 5
ENGINE
RADIATOR................................. 5-1
CARBURETOR.......................... 5-9
AIR INDUCTION SYSTEM....... 5-39
CAMSHAFTS........................... 5-45
CYLINDER HEAD.................... 5-67
VALVES AND VALVE
SPRINGS.................................. 5-75
CYLINDER AND PISTON........ 5-95
CLUTCH................................. 5-111
OIL FILTER ELEMENT,
WATER PUMP AND RIGHT
CRANKCASE COVER........... 5-129
BALANCER............................ 5-145
OIL PUMP.............................. 5-153
OIL TANK............................... 5-157
KICK SHAFT AND SHIFT
SHAFT.................................... 5-167
AC MAGNETO AND
STARTER CLUTCH............... 5-185
ENGINE REMOVAL............... 5-207
CRANKCASE AND
CRANKSHAFT....................... 5-221
TRANSMISSION, SHIFT CAM
AND SHIFT FORK................. 5-245
CHAPTER 6
CHASSIS
FRONT WHEEL
AND REAR WHEEL................... 6-1
FRONT BRAKE AND
REAR BRAKE.......................... 6-23
FRONT FORK.......................... 6-61
HANDLEBAR........................... 6-91
STEERING............................. 6-105
SWINGARM........................... 6-121
REAR SHOCK
ABSORBER........................... 6-141
CHAPITRE 4
MISE AU POINT
MOTEUR......................................... 4-1
CHÂSSIS........................................ 4-21
CHAPITRE 5
MOTEUR
RADIATEUR................................... 5-2
CARBURATEUR.......................... 5-10
SYSTEME D’INDUCTION
D’AIR.............................................. 5-40
ARBRES A CAMES...................... 5-46
CULASSE....................................... 5-68
SOUPAPES ET RESSORTS
DE SOUPAPES.............................. 5-76
CYLINDRE ET PISTON.............. 5-96
EMBRAYAGE............................. 5-112
ELEMENT DE FILTRE
A HUILE, POMPE A EAU
ET DEMI-CARTER DROIT...... 5-130
BALANCIER............................... 5-146
POMPE A HUILE....................... 5-154
RÉSERVOIR D’HUILE.............. 5-158
ARBRE DE KICK ET AXE
DE SELECTEUR......................... 5-168
ALTERNATEUR AVEC
ROTOR A ALIMENTATION
PERMANENTE ET
EMBRAYAGE DU
DEMARREUR............................. 5-186
DEPOSE DU MOTEUR.............. 5-208
CARTER MOTEUR ET
VILEBREQUIN........................... 5-222
BOITE DE VITESSES, TAMBOUR
ET FOURCHETTES DE
SELECTION................................ 5-246
CHAPITRE 6
CHÂSSIS
ROUE AVANT ET
ROUE ARRIERE............................ 6-2
FREIN AVANT ET FREIN
ARRIERE....................................... 6-24
FOURCHE..................................... 6-62
GUIDON......................................... 6-92
DIRECTION................................ 6-106
BRAS OSCILLANT.................... 6-122
AMORTISSEUR ARRIERE...... 6-142
1 - 12
GEN
INFO
SPECIAL TOOLS
YS-1880-A, 90890-01701 Sheave holder
This tool is used for when loosening or tightening the
flywheel magneto securing nut.
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-4111, 90890-04111
YM-4116, 90890-04116Valve guide remover
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to remove and install the valve
guide.
YM-4112, 90890-04112
YM-4117, 90890-04117Valve guide installer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to install the valve guide.
YM-4113, 90890-04113
YM-4118, 90890-04118Valve guide reamer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to rebore the new valve guide.
YM-04141, 90890-04141 Rotor puller
This tool is used to remove the flywheel magneto.
Part number Tool name/How to use Illustration
90890-03112
90890-04111
90890-04116
90890-04141
1 - 59
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
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
NOTE:Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” sec-
tion in the CHAPTER 2.
TORQUE-CHECK POINTS
1 - 65
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
REMISAGE
NETTOYAGE
Un nettoyage fréquent de la moto préser-
vera son apparence, maintiendra ses bon-
nes performances et augmentera la durée
de vie de nombre de ses composants.
1. Avant de nettoyer la moto, couvrir
la sortie du tuyau 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 à
l’aide d’un pinceau. Eviter tout con-
tact avec la chaîne, les pignons ou
les axes de roue.
3. Rincer la saleté et le dégraissant au
tuyau d’arrosage, en utilisant juste
la pression nécessaire.
ATTENTION:
Une pression excessive risque de cau-
ser des infiltrations d’eau dans les
roulements des roues, la fourche
avant, les freins et les joints de la
transmission. L’emploi abusif de
détergents sous forte pression, tels que
ceux utilisés dans les portiques de
lavage automatique, est nuisible à la
moto et peut entraîner des réparations
onéreuses.
4. Après avoir éliminé le plus gros de
la saleté au tuyau d’arrosage, laver
toutes les surfaces à l’eau chaude
savonneuse (employer un détergent
doux). Une vieille brosse à dents
convient parfaitement pour nettoyer
les parties difficiles d’accès.
5. Rincer immédiatement la moto à
l’eau claire et sécher toutes les sur-
faces à l’aide d’une peau de cha-
mois, d’une serviette ou d’un
chiffon doux absorbant.
6. Sécher immédiatement la chaîne à
l’aide d’une serviette en papier et la
graisser afin de la protéger contre la
rouille.
7. Nettoyer la selle à l’aide d’un pro-
duit de nettoyage pour similicuir
afin de conserver intacts la sou-
plesse et le lustre de la housse.
8. Une cire pour carrosserie peut être
utilisée pour toutes les surfaces
peintes et chromées. Ne pas
employer de cires détergentes car
elles contiennent souvent des abra-
sifs.
9. Lorsque le nettoyage est terminé,
mettre le moteur en marche et le
laisser tourner au ralenti pendant
plusieurs minutes.
CLEANING AND STORAGE
NETTOYAGE ET REMISAGE
1 - 67
GEN
INFO
EC1B2001STORAGE
If your machine is to be stored for 60
days or more, some preventive mea-
sures must be taken to avoid deterio-
ration. 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.
NOTE:Make any necessary repairs before
the machine is stored.REMISAGE
Si la moto doit être remisée pour 60
jours ou plus, il convient de prendre cer-
taines précautions pour éviter tout
endommagement. Après un nettoyage
complet de la moto, la préparer comme
suit pour le remisage:
1. Vidanger le réservoir de carburant,
le circuit de carburant et la cuve à
niveau constant du carburateur.
2. Déposer la bougie, verser une
cuillère à soupe d’huile moteur SAE
10W-30 dans le trou de bougie et
replacer la bougie. Enfoncer le
coupe-circuit du moteur et lancer
quelques fois le moteur à l’aide de
la pédale de kick afin de répartir
l’huile sur les parois du cylindre.
3. Déposer la chaîne de transmission,
la nettoyer soigneusement à l’aide
d’un solvant puis la graisser.
Remettre en place la chaîne ou la
conserver dans un sachet en plasti-
que (attaché au cadre pour éviter de
l’égarer).
4. Lubrifier tous les câbles de com-
mande.
5. Placer un support sous le cadre afin
de surélever les deux roues.
6. Couvrir la sortie du tuyau d’échap-
pement d’un sachet en plastique
pour empêcher la pénétration
d’humidité.
7. Si la moto doit être remisée dans un
lieu très humide ou exposé à l’air
marin, enduire toutes les surfaces
métalliques extérieures d’une fine
couche d’huile. Ne pas enduire
d’huile les parties en caoutchouc et
la housse de selle.
N.B.:
Effectuer toutes les réparations nécessai-
res avant de remiser la moto.
CLEANING AND STORAGE
NETTOYAGE ET REMISAGE
GENERAL SPECIFICATIONS
2 - 1
SPEC
EC200000
SPECIFICATIONS
EC211000
GENERAL SPECIFICATIONS
Model name: WR250FW (USA, CDN, AUS, NZ)
WR250F (EUROPE, ZA)
Model code number: 5UME (USA)
5UMF (EUROPE)
5UMG (CDN, AUS, NZ, ZA)
Dimensions: USA, ZA, CDN EUROPE, AUS, NZ
Overall length 2,165 mm (85.24 in) 2,180 mm (85.83 in)
Overall width 825 mm (32.48 in)←
Overall height 1,300 mm (51.18 in) 1,305 mm (51.38 in)
Seat height 980 mm (38.58 in) 990 mm (38.98 in)
Wheelbase 1,480 mm (58.27 in)←
Minimum ground clearance 365 mm (14.37 in) 370 mm (14.57 in)
Dry weight:
Without oil and fuel 106.0 kg (233.7 lb)
Engine:
Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 249 cm
3 (8.76 Imp oz, 8.42 US oz)
Bore × stroke 77.0 × 53.6 mm (3.03 × 2.11 in)
Compression ratio 12.5 : 1
Kick and electric starter
Starting system
Lubrication system: Dry sump
Oil type or grade:
Engine oil (For USA and CDN)
Yamalube 4, SAE10W30 or SAE20W40
Yamalube 4-R, SAE10W50
API service SG type or higher,
JASO standard MA
(Except for USA and CDN)
SAE10W30, SAE10W40, SAE15W40,
SAE20W40 or SAE20W50
API service SG type or higher,
JASO standard MA
-20 -10 0 10 20 30 40 50
˚C 0 10 30 50 70 90 110 130
˚F
YAMALUBE 4(10W-30) or SAE 10W-30
YAMALUBE 4(20W-40) or SAE 20W-40
YAMALUBE 4-R(10W-50) or SAE 10W-50
-20 -10 0 10 20 30 40 50
˚C
SAE 10W-30
SAE 10W-40
SAE 15W-40
SAE 20W-40
SAE 20W-50
2
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 310 mm (12.2 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 35/36.5 W × 1
Taillight 12 V 1.6/0.3 W × 1
MAINTENANCE SPECIFICATIONS
2 - 11
SPEC
NOTE:
- marked portion shall be checked for torque tightening after break-in. Hot starter cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Air filter case M6 × 1.0 2 8 0.8 5.8
Air filter joint and air filter case M5 × 0.8 1 4 0.4 2.9
Exhaust pipe M8 × 1.25 2 20 2.0 14
Exhaust pipe protector M6 × 1.0 3 10 1.0 7.2
Silencer M8 × 1.25 2 30 3.0 22
Silencer clamp M8 × 1.25 1 16 1.6 11
Spark arrester M5 × 0.8 4 7 0.7 5.1
Silencer cap M5 × 0.8 6 5 0.5 3.6
Air induction pipe M6 × 1.0 1 10 1.0 7.2
Air induction pipe clamp M6 × 1.0 1 4 0.4 2.9
Air cut-off valve assembly and bracket M6 × 1.0 2 10 1.0 7.2
Bracket (air cut-off valve) and frame M6 × 1.0 2 7 0.7 5.1
Crankcase M6 × 1.0 11 12 1.2 8.7
Crankcase bearing stopper M6 × 1.0 11 10 1.0 7.2
Crankcase bearing stopper (crankshaft) M6 × 1.0 4 10 1.0 7.2
Left crankcase cover M6 × 1.0 8 10 1.0 7.2
Idle gear cover (starter motor) M6 × 1.0 3 10 1.0 7.2
Idle gear plate M6 × 1.0 2 10 1.0 7.2
Right crankcase cover M6 × 1.0 6 10 1.0 7.2
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase oil drain bolt M10 × 1.25 1 20 2.0 14
Drive chain sprocket cover M6 × 1.0 2 8 0.8 5.8
Kick shaft ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kickstarter crank M8 × 1.25 1 33 3.3 24
Primary drive gear M18 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 5 10 1.0 7.2
Clutch boss M16 × 1.0 1 60 6.0 43
Clutch cable locknut M8 × 1.25 2 7 0.7 5.1
Push lever shaft M6 × 1.0 1 10 1.0 7.2
Drive sprocket M18 × 1.0 1 75 7.5 54
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Shift pedal M6 × 1.0 1 12 1.2 8.7 Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb