Yamaha WR450F, Owner'S Service Manual

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INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
VALVE CLEARANCE ADJUSTMENT
NOTE:
• The valve clearance should be adjusted
when the engine is cool to the touch.
• The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
• Seat
• Fuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
2. Remove:
• Air cut-off valve assembly
Refer to “AIR INDUCTION SYSTEM”
section in the CHAPTER 4.
• Spark plug
• Engine stay (upper)
• Cylinder head cover
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
3. Remove:
• Timing plug
1
• Straight plug
2
• O-ring
1
2
4. Check:
• Valve clearance
Out of specification
→
Adjust.
Valve clearance (cold):
Intake valve:
0.10 ~ 0.15 mm
(0.0039 ~ 0.0059 in)
Exhaust valve:
0.20 ~ 0.25 mm
(0.0079 ~ 0.0098 in)
Checking steps:
• Turn the crankshaft counterclockwise with
a wrench.
• Align the T.D.C. mark
a
on the rotor with
the align mark
b
on the crankcase cover
when piston is at T.D.C. on compression
stroke.
b
a