2003 YAMAHA WR 450F length

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks
ENGINE OIL
Replace
●

●

VALVES
Check the valve clearances
Inspect
Replace
●

●

●

●
The engine must be cold.
Check the valve seats
and valve stems for wear.
VALVE SPRINGS
Inspect
Replace
●

●
Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
●

●
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●

●
Inspect the camshaft sur-
face.
Inspect the decompres-
sion system
CAMSHAFT SPROCKETS
Inspect
Replace
●

●
Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
●

●

●

●
Inspect crack
Inspect carbon deposits
and eliminate them.
PISTON RING
Inspect
Replace
●

●

●
Check ring end gap
PISTON PIN
Inspect
Replace
●

●

CYLINDER HEAD
Inspect and clean
●
Inspect carbon deposits
and eliminate them.
Change gasket
CYLINDER
Inspect and clean
Replace
●

●
Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
●

●

●
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
●

●

3 - 33
INSP
ADJ

SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION
EC368000
SPROCKETS INSPECTION
1. Inspect:

Sprocket teeth
a

Excessive wear
→
Replace.
NOTE:

Replace the drive, driven sprockets and drive
chain as a set.
DRIVE CHAIN INSPECTION
1. Remove:

Drive chain
1

NOTE:

Remove the drive chain using a chain cutter
2
.
2. Clean:

Drive chain
Brush off as much dirt as possible.
Then clean the chain using the chain
cleaner.
CAUTION:

This machine has a drive chain with small
rubber O-rings
1
between the side plates.
Steam cleaning, high-pressure washes,
certain solvent and kerosene can damage
these O-rings.
1

3. Inspect:

O-ring
1
(drive chain)
Damage
→
Replace the drive chain.

Roller
2


Side plate
3
Damage/wear → Replace the drive
chain.
4. Measure:
Drive chain length (10 links) a
Out of specification → Replace.
Drive chain length (10 links):
: 150.1 mm (5.91 in)

3 - 40
INSP
ADJREAR SHOCK ABSORBER SPRING PRELOAD
ADJUSTMENT
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Remove:
Rear frame
3. Loosen:
Locknut 1
4. Adjust:
Spring preload
By turning the adjuster 2.
* For EUROPE, AUS, NZ and ZA
NOTE:
Be sure to remove all dirt and mud from
around the locknut and adjuster before
adjustment.
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
5. Tighten:
Locknut
6. Install:
Rear frame (upper)
Rear frame (lower) Stiffer →Increase the spring preload.
(Turn the adjuster 2 in.)
Softer →Decrease the spring preload.
(Turn the adjuster 2 out.)
Spring length (installed) a:
Standard length Extent of adjustment
246 mm (9.69 in)
* 246.5 mm (9.70 in)240.5 ~ 258.5 mm
(9.47 ~ 10.18 in)
T R..32 Nm (3.2 m · kg, 23 ft · lb)
T R..29 Nm (2.9 m · kg, 21 ft · lb)

4 - 24
ENGCAMSHAFTS
6. Remove:
Clips
Exhaust camshaft 1
Intake camshaft 2
NOTE:
Attach a wire 3 to the timing chain to prevent
it from falling into the crankcase.
1
2
3
INSPECTION
Camshaft
1. Inspect:
Cam lobes
Pitting/scratches/blue discoloration →
Replace.
2. Measure:
Cam lobes length a and b
Out of specification → Replace.
Cam lobes length:
Intake:
a31.200 ~ 31.300 mm
(1.2283 ~ 1.2323 in)
: 31.100 mm
(1.2244 in)
b22.550 ~ 22.650 mm
(0.8878 ~ 0.8917 in)
: 22.450 mm
(0.8839 in)
Exhaust:
a30.950 ~ 31.050 mm
(1.2185 ~ 1.2224 in)
: 30.850 mm
(1.2146 in)
b22.494 ~ 22.594 mm
(0.8856 ~ 0.8895 in)
: 22.394 mm
(0.8817 in)
3. Measure:
Runout (camshaft)
Out of specification → Replace.
Runout (camshaft):
Less than 0.03 mm (0.0012 in)

4 - 39
ENGVALVES AND VALVE SPRINGS
Valve spring
1. Measure:
Valve spring free length a
Out of specification → Replace.
2. Measure:
Compressed spring force a
Out of specification → Replace.
bInstalled length
Free length (valve spring):
Intake:
37.03 mm (1.46 in)
: 35.17 mm (1.38 in)
Exhaust:
37.68 mm (1.48 in)
: 35.79 mm (1.41 in)
Compressed spring force:
Intake:
111.3 ~ 127.9 N at 27.87 mm
(11.3 ~ 13.0 kg at 27.87 mm,
24.91 ~ 28.66 lb at 1.10 in)
Exhaust:
127.4 ~ 146.4 N at 27.38 mm
(13.0 ~ 14.9 kg at 27.38 mm,
28.66 ~ 32.85 lb at 1.08 in)
3. Measure:
Spring tilt a
Out of specification → Replace.
Spring tilt limit:
Intake:
2.5˚/1.61 mm (0.063 in)
Exhaust:
2.5˚/1.65 mm (0.065 in)
Valve lifter
1. Inspect:
Valve lifter
Scratches/damage → Replace both lift-
ers and cylinder head.

4 - 50
ENGCLUTCH
EC493000
REMOVAL POINTS
EC483211
Clutch boss
1. Remove:
Nut 1
Lock washer 2
Clutch boss 3
NOTE:
Straighten the lock washer tab and use the
clutch holding tool 4 to hold the clutch boss.
ÅFor USA and CDN
ıExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
Å
ı
EC494000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:
Clutch housing 1
Cracks/wear/damage → Replace.
Clutch boss 2
Scoring/wear/damage → Replace.
EC484201
Primary driven gear
1. Check:
Circumferential play
Free play exists → Replace.
Gear teeth a
Wear/damage → Replace.
EC484400
Clutch spring
1. Measure:
Clutch spring free length a
Out of specification → Replace springs
as a set.
Clutch spring free length:
Standard
48.4 mm (1.91 in) 47.4 mm (1.87 in)

5 - 31
CHAS

EC554200
Base valve
1. Inspect:

Valve assembly
1

Wear/damage
→
Replace.

O-ring
2

Damage
→
Replace.
EC554400
Fork spring
1. Measure:

Fork spring free length
a

Out of specification
→
Replace.
EC554502
Inner tube
1. Inspect:

Inner tube surface
a

Score marks
→
Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece
→
Replace.

Inner tube bends
Out of specification
→
Replace.
Use the dial gauge
1
.
NOTE:

The bending value is shown by one half of the
dial gauge reading.
WARNING

Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:

Outer tube
1

Score marks/wear/damage
→
Replace.
Fork spring free length:
Standard Limit
460 mm (18.1 in) 455 mm (17.9 in)
Inner tube bending limit:
0.2 mm (0.008 in)
FRONT FORK

5 - 66
CHASREAR SHOCK ABSORBER
2. Tighten:
Adjuster 1
3. Adjust:
Spring length (installed) a
* For EUROPE, AUS, NZ and ZA
NOTE:
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
ACHTUNG:CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
Spring length (installed) a:
Standard
lengthExtent of
adjustment
246 mm (9.69 in)
* 246.5 mm (9.70 in)240.5 ~ 258.5 mm
(9.47 ~ 10.18 in)
4. Tighten:
Locknut 1
Rear shock absorber
1. Install:
Dust seal 1
O-ring 2
Collar 3
NOTE:
Apply the molybdenum disulfide grease on
the bearing.
Apply the lithium soap base grease on the
dust seals, O-rings and collars.
New