2003 YAMAHA WR 250F brake

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
Air scoop and fuel tank M6 × 1.0 6 4 0.4 2.9
Air scoop and radiator guard (lower) M6 × 1.0 2 4 0.4 2.9
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 10 1.0 7.2
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
Headlight stay (lower) and lower bracket M8 × 1.25 2 7 0.7 5.1

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
7Throttle position sensor lead
8Neutral switch lead
9Oil hose
0Hose guideAAC magneto lead
BCylinder head breather hose
CStarter motor lead
DClutch cable
ERadiator hose 1
FRadiator pipe (radiator hose 4)
GCable guide
HNegative battery lead
ILight switch lead
JBrake hoseKCarburetor breather hose
LCarburetor overflow hose
MCoolant 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, light switch lead, wire
harness, starter motor lead, negative
battery lead and cylinder head breather
hose.

SPEC
2 - 101
CABLE ROUTING DIAGRAM
ÖFasten the neutral switch lead and AC magneto lead.
×Pass the cylinder head breather hose on the inside of the radi-
ator hose 1 and on the outside of the radiator pipe (radiator
hose 4). Make sure that the cylinder head breather hose does
not go forward of the chassis.
ØPass the starter motor lead in front of the radiator hose 4.
ÙPass the clutch cable through the cable guide.
ÚPass the wire harness on the outside of the neutral switch lead
and AC magneto lead.
ÛFit the brake hose into the guides on the protector.
ÜPass the wire harness, clutch cable and light switch lead
through the cable guide.ÝFasten the AC magneto lead, neutral switch lead and light
switch lead to the cable guide at their protecting tube with a
plastic locking tie and cut off the tie end.
ÞPass the carburetor breather hoses, carburetor overflow hose
and coolant reservoir breather hose so that the hoses do not
contact the rear shock absorber.

SPEC
2 - 107
CABLE ROUTING DIAGRAM
1Brake master cylinder
2Brake hose holder
3Brake hoseÈInstall the brake hose so that its pipe portion directs as shown
and lightly touches the projection on the brake caliper.
ÉPass the brake hose into the brake hose holders.
ÊIf the brake hose contacts the spring (rear shock absorber),
correct its twist.
ËInstall the brake hose so that its pipe portion directs as shown
and lightly touches the projection on the brake master cylinder.

SPEC
2 - 111
CABLE ROUTING DIAGRAM
1Throttle cable
2Brake hose
3Clamp
4Light switch lead
5Hot starter cable
6Clutch cable
7Hose guide
8Clutch switch lead
9Engine stop switch lead
0Trip meter cable
AMain switch lead
BTrip meter
CMain switchDLight switch
EStart switch lead
ÈFasten the start switch lead and light switch lead.
ÉFasten the engine stop switch lead and clutch switch lead.
ÊPass the brake hose through the hose guide.
ËPass the start switch lead in front of the main switch lead.
ÌFasten the start switch lead.
ÍPass the hot starter cable, clutch cable and light switch lead
between the upper bracket and coupler bracket.
ÎPass the throttle cables between the upper bracket and trip
meter.

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
ROTOR NUT
Retighten
EXHAUST PIPE, SILENCER,
PROTECTOR
Inspect and retighten
Clean
Replace* Whichever comes first
*SPARK ARRESTER
Clean
(Every
six
months)
CRANK
Inspect and clean
CARBURETOR
Inspect, adjust and clean
SPARK PLUG
Inspect and clean
Replace
DRIVE CHAINUse chain lube
Chain slack:
40 ~ 50 mm (1.6 ~ 2.0 in) Lubricate, slack, alignment
Replace
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolantEvery two years
Inspect hoses
OUTSIDE NUTS AND BOLTS Refer to “STARTING AND
BREAK-IN” section in the
CHAPTER 1. Retighten
AIR FILTER
Clean and lubricate Use foam air-filter oil or
equivalent oil
Replace
OIL FILTER
Replace
OIL STRAINER (frame)
Clean
FRAME
Clean and inspect
FUEL TANK, COCK
Clean and inspect
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper bolts,
master cylinder bolts and union bolts
Replace pads
Replace brake fluid Every one yearItemAfter
break-inEvery
race
Every third
(or
500 km)Every fifth
(or
1,000 km)As
requiredRemarks
1
2
3
4
5
6
7

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.3-83 ~ 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 - 65
INSP
ADJ
EC360000
CHASSIS
EC361012BRAKE SYSTEM AIR BLEEDING
WARNING
Bleed the brake system if:
The system has been disassem-
bled.
A brake hose has been loosened
or removed.
The brake fluid is very low.
The brake operation is faulty.
A dangerous loss of braking per-
formance may occur if the brake
system is not properly bled.
1. Remove:
Brake master cylinder cap
Diaphragm
Protector (rear brake)
2. Bleed:
Brake fluid
ÈFront
ÉRear
Air bleeding steps:
a. Add proper brake fluid to the
reservoir.
b. Install the diaphragm. Be care-
ful not to spill any fluid or allow
the reservoir to overflow.
c. Connect the clear plastic tube
2 tightly to the caliper bleed
screw
1.
d. Place the other end of the tube
into a container.
e. Slowly apply the brake lever or
pedal several times.
f. Pull the lever in or push down
on the pedal. Hold the lever or
pedal in position.
g. Loosen the bleed screw and
allow the lever or pedal to
travel towards its limit.
h. Tighten the bleed screw when
the lever or pedal limit has
been reached; then release the
lever or pedal.
T R..
Bleed screw:
6 Nm
(0.6 m  kg, 4.3 ft  lb)
i. Repeat steps (e) to (h) until of
the air bubbles have been
removed from the system.
È
É
PARTIE CYCLE
PURGE DE L’AIR DU SYSTEME
DE FREINAGE
AVERTISSEMENT
Purger le système de freinage si:
Le système a été démonté.
Un tuyau de frein a été desserré ou
deposé.
Le liquide de frein est très bas.
Le frein fonctionne mal.
Si le système de freinage n’est pas cor-
rectement purgé, cela peut se traduire
par une dangereuse perte d’efficacité
de freinage.
1. Déposer:
Couvercle de maître-cylindre de
frein
Diaphragme
Protection (frein arrière)
2. Purger:
Liquide de frein
È
Avant
É
Arrière
Etapes de purge de l’air:
a. Ajouter du liquide de frein correct
dans le réservoir.
b. Mettre en place le diaphragme.
Prendre garde à ne pas renverser
ou faire déborder le réservoir.
c. Connecter hermétiquement le
tuyau transparent en matière plas-
tique 2, à la vis de purge 1 de
l’étrier.
d. Mettre l’autre extrémité du tuyau
dans un récipient.
e. Actionner légèrement plusieurs
fois le levier ou la pédale de frein.
f. Appuyer sur le levier ou la pédale
de frein et le maintenir dans cette
position.
g. Desserrer la vis de purge et laisser
le levier ou la pédale s’enfoncer
sur toute sa course.
h. Resserrer la vis de purge quand le
levier ou la pédale a atteint sa
limite.
Relâcher ensuite le levier ou la
pédale.
T R..
Vis de purge:
6 Nm
(0,6 m  kg, 4,3 ft  lb)
i. Refaire le opérations (e) à (h)
jusqu’à l’élimination totale des
bulles d’air du système.
CHASSIS
PARTIE CYCLE