steering YAMAHA WR 250F 2006 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
AIR INDUCTION SYSTEM....... 4-51
CAMSHAFTS........................... 4-57
CYLINDER HEAD.................... 4-79
VALVES AND VALVE
SPRINGS.................................. 4-87
CYLINDER AND PISTON...... 4-107
CLUTCH................................. 4-123
OIL FILTER ELEMENT,
WATER PUMP AND RIGHT
CRANKCASE COVER........... 4-141
BALANCER............................ 4-157
OIL PUMP.............................. 4-165
KICK SHAFT AND
SHIFT SHAFT........................ 4-175
AC MAGNETO AND
STARTER CLUTCH............... 4-193
ENGINE REMOVAL............... 4-215
CRANKCASE AND
CRANKSHAFT....................... 4-229
TRANSMISSION, SHIFT CAM
AND SHIFT FORK................. 4-253
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............................. 5-105
SWINGARM........................... 5-121
REAR SHOCK ABSORBER... 5-141
CHAPITRE 4
MOTEUR
SELLE, RESERVOIR DE
CARBURANT ET CACHES
LATERAUX..................................... 4-2
TUBE D’ECHAPPEMENT ET
SILENCIEUX................................... 4-8
RADIATEUR................................. 4-14
CARBURATEUR.......................... 4-22
SYSTEME D’INDUCTION
D’AIR.............................................. 4-52
ARBRES A CAMES...................... 4-58
CULASSE....................................... 4-80
SOUPAPES ET RESSORTS DE
SOUPAPES..................................... 4-88
CYLINDRE ET PISTON............ 4-108
EMBRAYAGE............................. 4-124
ELEMENT DE FILTRE A
HUILE, POMPE A EAU ET
DEMI-CARTER DROIT............ 4-142
BALANCIER............................... 4-158
POMPE A HUILE....................... 4-166
ARBRE DE KICK ET
AXE DE SELECTEUR............... 4-176
ALTERNATEUR AVEC ROTOR A
ALIMENTATION PERMANENTE
ET EMBRAYAGE DU
DEMARREUR............................. 4-194
DEPOSE DU MOTEUR.............. 4-216
CARTER MOTEUR ET
VILEBREQUIN........................... 4-230
BOITE DE VITESSES, TAMBOUR
ET FOURCHETTES DE
SELECTION................................ 4-254
CHAPITRE 5
CHASSIS
ROUE AVANT ET ROUE
ARRIERE......................................... 5-2
FREIN AVANT ET FREIN
ARRIERE....................................... 5-24
FOURCHE..................................... 5-62
GUIDON......................................... 5-92
DIRECTION................................ 5-106
BRAS OSCILLANT.................... 5-122
AMORTISSEUR ARRIERE...... 5-142

1 - 11
GEN
INFO
SPECIAL TOOLS
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.
NOTE: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-3097, 90890-01252
YU-1256Dial gauge and stand
Stand
These tools are used to check each part for runout or
bent.
YU-90050, 90890-01274
YU-90050, 90890-01275
YM-91044, 90890-04081
YU-90063, 90890-01278Crankshaft installing tool
Crankshaft installing pot
Crankshaft installing bolt
Spacer (crankshaft installer)
Adapter (M12)
These tools are used to install the crankshaft.
YU-1304, 90890-01304 Piston pin puller set
This tool is used to remove the piston pin.
YU-24460-01, 90890-01325
YU-33984, 90890-01352Radiator cap tester
Radiator cap tester adapter
These tools are used for checking the cooling
system.
YU-33975, 90890-01403 Steering nut wrench
This tool is used when tighten the steering ring nut to
specification.
YM-01494, 90890-01494 Damper rod holder
Use this tool to remove and install the damper rod.
YM-A0948, 90890-01502 Fork seal driver
This tool is used when install the fork oil seal.90890-01135
90890-01304
90890-01325
90890-01352
YM-0149490890-01494
YM-A094890890-01502

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

MAINTENANCE SPECIFICATIONS
2 - 12
SPEC
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN EUROPE AUS, NZ, ZA
Front fork travel 300 mm (11.8 in)←←
Fork spring free length 460 mm (18.1 in)←←
Spring rate, STD K = 4.2 N/mm
(0.428 kg/mm,
24.0 lb/in)←K = 4.3 N/mm
(0.438 kg/mm,
24.5 lb/in)
Optional spring/spacer Yes←←
Oil capacity 650 cm
3
(22.9 Imp oz,
22.0 US oz) ←←
Oil level 130 mm (5.12 in)←←

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)95 ~ 150 mm
(3.74 ~ 5.91 in)←←
Oil grade Suspension oil
“S1”←←
Inner tube outer diameter 48 mm (1.89 in)←←
Front fork top end 5 mm (0.20 in)←←
Rear suspension: USA, CDN EUROPE AUS, NZ, ZA
Shock absorber travel 129 mm (5.08 in)← ←
Spring free length260 mm (10.24 in)← ←
Fitting length 248 mm (9.76 in) 246 mm (9.69 in) 247.5 mm (9.74 in)
237.5 ~ 258.5 mm
(9.35 ~ 10.18 in)← ←
Spring rate, STD K = 50.0 N/mm
(5.10 kg/mm,
285.6 lb/in)K = 46.0 N/mm
(4.70 kg/mm,
263.2 lb/in)K = 52.0 N/mm
(5.30 kg/mm,
296.8 lb/in)
Optional spring Yes← ←
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)← ←
Swingarm:
Swingarm free play limit
End ---- 1.0 mm
(0.04 in)

MAINTENANCE SPECIFICATIONS
2 - 14
SPEC
NOTE:
1. First, tighten the steering ring nut approximately 38 Nm (3.8 m  kg, 27 ft  lb) by using the steer-
ing nut wrench, then loosen the steering ring nut one turn.
2. Retighten the steering ring 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 handlebar lower
holderM8 × 1.25 4 28 2.8 20
Handlebar lower holder and upper bracket M12 × 1.25 2 40 4.0 29
Steering stem and steering ring nut M28 × 1.0 1 Refer to NOTE.
Front fork and front fork cap bolt M51 × 1.5 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 7 0.7 5.1
Front fork protector and brake hose holder M6 × 1.0 2 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 and front brake hose
guide bracketM5 × 0.8 1 4 0.4 2.9
Front brake hose guide and lower bracket M6 × 1.0 1 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
Front brake caliper and brake hose holder M6 × 1.0 1 10 1.0 7.2
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 90 9.0 65
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 10 1.0 7.2
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

SPEC
2 - 97
CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1Fuel tank breather hose
2Oil tank breather hose
3Clamp
4Diode
5Wire harness
6Hot starter cable
7Cylinder head breather hose
8Throttle position sensor lead
9Neutral switch lead
0Oil hoseAClutch cable
BStarter motor lead
CNegative battery lead
DCable guide
EBrake hose
FRectifier/regulator lead
GAC magneto lead
HRectifier/regulator
ICarburetor breather hoseJCarburetor overflow hose
KCoolant reservoir breather hose
ÈInsert the fuel tank breather hose into
the hole in the steering stem cap.
ÉPass the oil tank breather hose on the
outside of the AC magneto lead, neu-
tral switch lead, wire harness, starter
motor lead, negative battery lead and
cylinder head breather hose.
B
B
B-B
A
Ô3B
Ó3 Ö
C
× EF
9
GÙ
H
Ú
Û
1
È
3
Ê
4
Ë
5
6
7 Ì
ÍÎ
Ï
Ñ Ð
8
0 3
ÒÜ II
JK
9 A 2
É
0
9A
ØD ØD
Õ

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
*marked: For USAFRONT FORKS
Inspect and adjust
Replace oilSuspension oil “S1”
Replace oil seal
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubeLithium base grease
PROTECTOR GUIDE
Replace
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.1-49
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.1-59
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 ~ 40

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
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:Apply the lithium soap base
grease on the thread of the
steering stem.
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 des roulements
Il y a du jeu → Remplacer.
CONTROLE ET REGLAGE DE LA
TETE DE FOURCHE
1. Surélever la roue avant en plaçant
un support adéquat sous le moteur.
2. Contrôler:
Colonne de direction
Saisir les bras de fourche par le
bas et secouer doucement la four-
che d’avant en arrière.
Jeu → Régler la tête de fourche.
3. Contrôler:
Fonctionnement régulier de la
direction
Tourner le guidon de butée à
butée.
Fonctionnement irrégulier →
Régler l’écrou de blocage de la
direction.
4. Régler:
Ecrou de blocage de la direction
Etapes de réglage de l’écrou de blo-
cage de la direction:
Déposer le phare.
Déposer le guidon et le té supé-
rieur.
Desserrer l’écrou de blocage de la
direction 1 à l’aide de la clé pour
écrou de direction 2.
Clé pour écrou de
direction:
YU-33975/90890-01403
Serrer l’écrou de blocage de la
direction 3 à l’aide de la clé pour
écrou de direction 4.
N.B.:
Appliquer de la graisse à savon de
lithium sur le filet de la colonne de
direction.
Adapter la clé dynamométrique à
la clé pour écrou de direction de
manière à ce qu’elles forment un
angle droit.
Clé pour écrou de
direction:
YU-33975/90890-01403
T R..
Ecrou de blocage de la
direction (serrage initial):
38 Nm
(3,8 m  kg, 27 ft  lb)
CHASSIS
CHASSIS

3 - 103
INSP
ADJ
Loosen the steering ring nut
one turn.
Retighten the steering ring nut
using the steering nut wrench.
WARNING
Avoid over-tightening.
T R..
Steering ring nut
(final tightening):
7 Nm
(0.7 m  kg, 5.1 ft  lb)
Check the steering stem by
turning it lock to lock. If there is
any binding, remove the steer-
ing stem assembly and inspect
the steering bearings.
Install the washer
5, upper
bracket
6, washer
7, steering
stem nut
8, steering stem cap
9, handlebar
0, handlebar
upper holder
A and headlight
B.
NOTE:The handlebar upper holder
should be installed with the
punched mark
a forward.
Install the handlebar so that the
marks
b are in place on both
sides.
Insert the end of the fuel
breather hose
C into the hole in
the steering stem cap.
CAUTION:
First tighten the bolts on the
front side of the handlebar
upper holder, and then tighten
the bolts on the rear side.
T R..
Steering stem nut:
145 Nm
(14.5 m  kg, 105 ft  lb)
Handlebar upper holder:
28 Nm
(2.8 m  kg, 20 ft  lb)
Pinch bolt (upper
bracket):
23 Nm
(2.3 m  kg, 17 ft  lb)
Headlight (left and right):
7 Nm
(0.7 m  kg, 5.1 ft  lb)
Headlight (lower):
7 Nm
(0.7 m  kg, 5.1 ft  lb)
Dévisser d’un tour l’écrou de blo-
cage de la direction.
Resserrer l’écrou de blocage de la
direction à l’aide de la clé pour
écrou de direction.
AVERTISSEMENT
Eviter de serrer à l’excès.
T R..
Ecrou de blocage de la
direction (serrage final):
7 Nm
(0,7 m  kg, 5,1 ft  lb)
Contrôler la colonne de direction
en la tournant d’une butée à l’autre.
S’il y a la moindre gêne, démonter
la colonne de direction et contrôler
les paliers de la direction.
Monter la rondelle 5, le té supé-
rieur 6, la rondelle 7, l’écrou de
blocage de la direction 8, le capu-
chon de la colonne de direction 9,
le guidon 0, le demi-palier de gui-
don supérieur A et le phare B.
N.B.:
Le demi-palier supérieur du guidon
doit être monté avec son poinçon
a vers l’avant.
Monter le guidon de façon à ce que
les repères b soient en place des
deux côtés.
Introduire l’extrémité de la durit de
mise à l’air du réservoir de carbu-
rant C dans le trou du capuchon de
la colonne de direction.
ATTENTION:
Serrer d’abord les boulons situés à
l’avant du demi-palier supérieur
du guidon, puis les boulons situés à
l’arrière.
T R..
Ecrou de direction:
145 Nm
(14,5 m  kg, 105 ft  lb)
Demi-palier supérieur de
guidon:
28 Nm
(2,8 m  kg, 20 ft  lb)
Boulon de pincement (té
supérieur):
23 Nm
(2,3 m  kg, 17 ft  lb)
Phare (gauche et droit):
7 Nm
(0,7 m  kg, 5,1 ft  lb)
Phare (inférieur):
7 Nm
(0,7 m  kg, 5,1 ft  lb)
CHASSIS
CHASSIS