Yamaha YFM660FS, Supplementary Service Manual

Page: 223 / 478

4 - 10
ENG
CYLINDER HEAD COVER
REMOVING THE CYLINDER HEAD COVER
1.Align:
●
“I” mark
(with stationary pointer)
*****************************************************
Checking steps:
●
Turn the crankshaft counterclockwise with a
wrench.
●
Align the “I” mark
1
on the rotor with the sta-
tionary pointer
2
on the crankcase cover.
When the “I” mark is aligned with the station-
ary pointer, the piston is at the Top Dead
Center (T.D.C.).
NOTE:
●
When the piston is at the top dead center
(T.D.C.) on the compression stroke, there
should be clearance between the valve stem
tips and their respective rocker arm adjusting
screws.
●
If there is no clearance, rotate the crankshaft
counterclockwise one turn.
*****************************************************
2.Remove:
●
Cylinder head cover
NOTE:
Loosen each bolt 1/4 of a turn at a time, in
stages and in a crisscross pattern. After all the
bolts are loosened, remove them.
CHECKING THE CYLINDER HEAD COVER
1.Check:
●
Cylinder head cover
Cracks/damage
→
Replace the cylinder
head cover and cylinder head as a set.