2003 YAMAHA YZ250F rear shock

CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS ................................. 4-1
EXHAUST PIPE AND SILENCER ............ 4-3
RADIATOR ................................................ 4-5
CARBURETOR ......................................... 4-8
CAMSHAFTS .......................................... 4-21
CYLINDER HEAD ................................... 4-30
VALVES AND VALVE SPRINGS ........... 4-33
CYLINDER AND PISTON ....................... 4-42
CLUTCH .................................................. 4-49
OIL FILTER ELEMENT, WATER PUMP
AND RIGHT CRANKCASE COVER ...... 4-56
BALANCER ............................................ 4-63
OIL PUMP ............................................... 4-66
KICK SHAFT AND SHIFT SHAFT .......... 4-71
CDI MAGNETO ....................................... 4-78
ENGINE REMOVAL ................................ 4-82
CRANKCASE AND CRANKSHAFT ....... 4-87
TRANSMISSION, SHIFT CAM
AND SHIFT FORK .................................. 4-96
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL ...... 5-1
FRONT BRAKE AND REAR BRAKE ..... 5-10
FRONT FORK ......................................... 5-26
HANDLEBAR .......................................... 5-39
STEERING .............................................. 5-45
SWINGARM ............................................ 5-50
REAR SHOCK ABSORBER ................... 5-58

GEN
INFO
1 - 18
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Frame construction
Combined seat and fuel tank
Exhaust system
Engine mounting
Steering Steering stem to
handlebar
Suspension Front Steering stem to front
fork
Rear For link type
Rear Installation of rear
shock absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel system
Lubrication systemFrame to rear frame
Fuel tank to frame
Silencer to rear frame
Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Rear shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of axle holder
Tightening of wheel axle
Wheel to rear wheel sprocket
Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Fuel tank to fuel cock
Tightening of oil hose clamp
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

SPEC

2 - 3
GENERAL SPECIFICATIONS
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 magneto

SPEC
2 - 12
MAINTENANCE SPECIFICATIONS
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN
AUS, NZ, ZAEUROPE
Front fork travel 300 mm (11.8 in)←----
Fork spring free length 460 mm (18.1 in)←455 mm (17.9 in)
Spring rate, STD K = 4.22 N/mm
(0.43 kg/mm,
24.1 lb/in)K = Approx.
4.22 N/mm
(0.43 kg/mm,
24.1 lb/in)----
Optional spring/spacer Yes←----
Oil capacity 563 cm
3
(19.8 Imp oz,
19.0 US oz) 573 cm3
(20.2 Imp oz,
19.4 US oz)----
Oil level 140 mm (5.51 in) 130 mm (5.12 in) ----

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 150 mm
(3.15 ~ 5.91 in)←----
Oil grade Suspension oil
“01”←----
Inner tube outer diameter 46 mm (1.81 in)←----
Front fork top end 5 mm (0.20 in)←----
Rear suspension: USA, CDN,
AUS, NZ, ZAEUROPE
Shock absorber travel 132 mm (5.20 in)←----
Spring free length 260 mm
(10.24 in)275 mm
(10.83 in)----
Fitting length 248 mm
(9.76 in)260 mm
(10.24 in)----
240.5~ 258.5 mm
(9.47 ~ 10.18 in)255.5~ 273.5 mm
(10.06 ~ 10.77 in)----
Spring rate, STD K = 46.0 N/mm
(4.70 kg/mm,
263.2 lb/in)K = Approx.
48.0 N/mm
(4.90 kg/mm,
274.4 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)

SPEC
2 - 15
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.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 42 4.2 30
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
Right engine guard M8 × 1.25 2 23 2.3 17
CDI unit bracket M6 × 1.0 1 10 1.0 7.2
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
Radiator cover M6 × 1.0 6 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
Number plate M6 × 1.0 1 7 0.7 5.1

2 - 19
SPECCABLE ROUTING DIAGRAM
ÒMake sure that the throttle
position sensor lead coupler
does not go out side the chas-
sis.
˜Fasten the throttle position
sensor lead.
ˆFasten the neutral switch lead
on the oil hose with a plastic
locking tie and cut off the tie
end.
ØFasten the neutral switch lead.
∏Fasten the neutral switch lead
and CDI magneto lead.
ŒPass the neutral switch lead,
CDI magneto lead and radiator
breather hose between the
radiator and frame.ÂPass the carburetor breather
hoses and overflow hose so
that all there hoses do not con-
tact the rear shock absorber.

2 - 21
SPECCABLE ROUTING DIAGRAM
1Brake master cylinder
2Brake hose holder
3Brake hoseÅInstall the brake hose so that its pipe portion
directs as shown and lightly touches the projection
on the brake caliper.
ıPass the brake hose into the brake hose holders.
ÇIf the brake hose contacts the spring (rear shock
absorber), correct its twist.
ÎInstall the brake hose so that its pipe portion
directs as shown and lightly touches the projection
on the brake master cylinder.

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
●
●
●
●
● Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
● ● Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
●
●
●
●
●
(After
rain ride)
●Molybdenum disulfide
grease
DRIVE CHAIN GUIDE AND ROLLERS
Inspect
● ●
SWINGARM
Inspect, lube and retighten
● ● Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect, lube and retighten
● ● Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
● ●
●
● Lithium base grease
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate
●
●
●
●
●
●
●
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Lubricate
Inspect and clean (throttle cable)
●
●
● ●

●
● Yamaha cable lube or
SAE 10W-30 motor oil
Inspect dirt and wear on
the throttle cable on the
carburetor side.
HOT STARTER, CLUTCH LEVER
Inspect free play
●
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks