Yamaha XVZ13TF 1999 Service Manual page 175

VALVES AND VALVE SPRINGS
4. Lap:
S valve face
S valve seat
NOTE:
After replacing the cylinder head or replacing
the valve and valve guide, the valve seat and
valve face should be lapped.
a. Apply a coarse lapping compound a to the
CAUTION:
Do not let the lapping compound enter the
gap between the valve stem and the valve
guide.
b. Apply molybdenum disulfide oil onto the
c. Install the valve into the cylinder head.
d. Turn the valve unit the valve face and valve
NOTE:
For the best lapping results, lightly tap the valve
seat while rotating the valve back and forth be-
tween your hand.
e. Apply a fine lapping compound to the valve
f. After every lapping procedure, be sure to
g. Apply Mechanic's blueing dye (Dykem) b
h. Install the valve into the cylinder head.
i. Press the valve through the valve guide and
4-31
valve face.
valve stem.
seat are evenly polished, then clean off all of
the lapping compound.
face and repeat the above steps.
clean off all of the lapping compound from
the valve face and valve seat.
onto the valve face.
onto the valve seat to make a clear impres-
sion.
ENG