2007 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
The engine must be cold.
Check the valve seats
and valve stems for wear. Check the valve clearances
Inspect
Replace
VALVE SPRINGS
Check the free length and
the tilt. Inspect
Replace
VALVE LIFTERS
Check for scratches and
wear. Inspect
Replace
CAMSHAFTS Inspect the camshaft sur-
face.
Inspect the decompres-
sion system Inspect
Replace
CAMSHAFT SPROCKETS
Check for wear on the
teeth and for damage. Inspect
Replace
PISTON
Inspect crack
Inspect carbon deposits
and eliminate them. Inspect
Clean
Replace
PISTON RING
Check ring end gap Inspect
Replace
PISTON PIN
Inspect
Replace
CYLINDER HEAD Inspect carbon deposits
and eliminate them.
Change gasket Inspect and clean
CYLINDER
Inspect and clean
Inspect score marks
Inspect wear
Replace
CLUTCH
Inspect housing, friction
plate, clutch plate and
spring Inspect and adjust
Replace
TRANSMISSION
Inspect
Replace bearing
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectInspect wear

3 - 32
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. Measure:
Drive chain length (15 links) a
Out of specification → Replace.
NOTE:
While measuring the drive chain length, push
down on the drive chain to increase its ten-
sion.
Measure the length between drive chain
roller 1 and F as shown.
Perform this measurement at two or three
different places.
Drive chain length (15 links):
: 239.3 mm (9.42 in)
2. Remove:
Drive chain 1
NOTE:
Remove the drive chain using a chain cutter
2.
3. 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 - 39
INSP
ADJREAR SHOCK ABSORBER SPRING PRELOAD
ADJUSTMENT
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Remove:
Rear frame
3. Loosen:
Locknut 1
4. Adjust:
Spring preload
By turning the adjuster 2.
* For EUROPE
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
252.5 mm (9.94 in)
* 251.5 mm (9.90 in)238.5 ~ 258.5 mm
(9.39 ~ 10.18 in)
T R..38 Nm (3.8 m · kg, 27 ft · lb)
T R..32 Nm (3.2 m · kg, 23 ft · lb)

4 - 27
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:
a30.100 ~ 30.200 mm
(1.1850 ~ 1.1890 in)
: 30.000 mm
(1.1811 in)
b22.450 ~ 22.550 mm
(0.8839 ~ 0.8878 in)
: 22.350 mm
(0.8799 in)
Exhaust:
a30.200 ~ 30.300 mm
(1.1890 ~ 1.1929 in)
: 30.100 mm
(1.1850 in)
b22.450 ~ 22.550 mm
(0.8839 ~ 0.8878 in)
: 22.350 mm
(0.8799 in)
3. Measure:
Runout (camshaft)
Out of specification → Replace.
Runout (camshaft):
Less than 0.03 mm (0.0012 in)

4 - 43
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:
39.46 mm (1.55 in)
: 38.46 mm (1.51 in)
Exhaust:
37.61 mm (1.48 in)
: 36.61 mm (1.44 in)
Compressed spring force:
Intake:
130.2 ~ 149.8 N at 27.87 mm
(13.28 ~ 15.28 kg at 27.87 mm,
29.27 ~ 33.68 lb at 1.10 in)
Exhaust:
123.1 ~ 141.7 N at 28.38 mm
(12.55 ~ 14.45 kg at 28.38 mm,
27.67 ~ 31.85 lb at 1.12 in)
3. Measure:
Spring tilt a
Out of specification → Replace.
Spring tilt limit:
Intake:
2.5°/1.7 mm (0.067 in)
Exhaust:
2.5°/1.6 mm (0.063 in)
Valve lifter
1. Inspect:
Valve lifter
Scratches/damage → Replace both lift-
ers and cylinder head.

4 - 54
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.
ÈFor USA and CDN
ÉExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
ÈÉ
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
50.0 mm (1.97 in) 49.0 mm (1.93 in)

5 - 30
CHAS
EC554200
Base valve
1. Inspect:
Valve assembly 1
Wear/damage → Replace.
O-ring 2
Damage → Replace.
2
1
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)
Refer to “REAR SHOCK ABSORBER
SPRING PRELOAD ADJUSTMENT” sec-
tion in the CHAPTER 3.
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 dust seal lips and collars.
•Apply the lithium soap base grease on the O-
rings.
New