Yamaha YZ450FA 2011, Owner'S Service Manual

Page: 87 / 318

3-16
ENGINE
ADJUSTING THE VALVE CLEARANCE
• This section is intended for those who have
basic knowledge and skill concerning the ser-
vicing of Yamaha motorcycles (e.g., Yamaha
dealers, service engineers, etc.) Those who
have little knowledge and skill concerning ser-
vicing are requested not to undertake inspec-
tion, adjustment, disassembly, or reassembly
only by reference to this manual. It may lead
to servicing trouble and mechanical damage.
• The valve clearance should be adjusted when
the engine is cool to the touch.
1. Remove:
• Seat
Refer to "SEAT AND SIDE COVERS" sec-
tion in the CHAPTER 4.
• Fuel tank
Refer to "FUEL TANK" section in the CHAP-
TER 6.
2. Remove:
• Spark plug
• Cylinder head cover
Refer to "CAMSHAFTS" section in the
CHAPTER 4.
3. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
• O-ring
4. Check:
• Valve clearance
Out of specification
→
Adjust.
Checking steps:
a. Turn the crankshaft counterclockwise with a
wrench.
b. Align the alignment mark "a" on the rotor
with the alignment mark "b" on the crank-
case cover.
Make sure that the alignment mark "c" on the
exhaust camshaft sprocket and the alignment
mark "d" on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
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)