Yamaha 2011 WR250FA Owner's Service Manual page 97

ADJUSTING THE VALVE CLEARANCE
This section is intended for those who have ba-
sic knowledge and skill concerning the servic-
ing 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.
• 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.
2. Drain:
• Coolant
Refer to "CHANGING THE COOLANT" sec-
tion.
3. Remove:
• Right radiator
Refer to "RADIATOR" section in the CHAP-
TER 5.
• Carburetor
Refer to "CARBURETOR" section in the
CHAPTER 5.
• Spark plug
• Upper engine bracket
• Cylinder head cover
Refer to "CAMSHAFTS" section in the
CHAPTER 5.
4. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
• O-ring
5. Check:
• Valve clearance
Out of specification → Adjust.
Valve clearance (cold):
Intake valve:
0.10–0.15 mm (0.0039–0.0059 in)
Exhaust valve:
0.17–0.22 mm (0.0067–0.0087 in)
Checking steps:
a. Turn the crankshaft counterclockwise with a
wrench.
b. 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.
3-22
ENGINE