Yamaha YZ250F(P)/LC Owner's Service Manual page 202

VALVE CLEARANCE INSPECTION AND ADJUSTMENT
Checking steps:
Turn the crankshaft counterclockwise with
G
a wrench.
NOTE:
Squeezing the decompression lever allows
the crankshaft to be turned easily.
Align the T.D.C. mark a on the rotor with
G
the align mark b on the crankcase cover
when piston is at T.D.C. on compression
stroke.
NOTE:
In order to be sure that the piston is at Top
Dead Center, the punch mark c on the
exhaust camshaft and the punch mark d on
the intake camshaft must align with the cyl-
inder head surface, as shown in the illustra-
tion.
Measure the valve clearance e using a
G
feeler gauge 1.
NOTE:
Record the measured reading if the clear-
ance is incorrect.
6. Adjust:
Valve clearance
G
Adjustment steps:
Remove the camshaft (intake and exhaust).
G
Refer to "CAMSHAFTS" section in the
CHAPTER 4.
3 - 21
INSP
ADJ