Checking The Valve Seats - Yamaha 2002 TDM900 Service Manual

VALVES AND VALVE SPRINGS
EAS00240

CHECKING THE VALVE SEATS

The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
S carbon deposits
(from the valve face and valve seat)
2. Check:
S valve seat
Pitting/wear ! Replace the cylinder head.
3. Measure:
S valve seat width a
Out of specification ! Replace the cylinder
head.
a. Apply Mechanic's blueing dye (Dykem) b
onto the valve face.
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
onto the valve seat to make a clear impres-
sion.
d. Measure the valve seat width.
NOTE:
Where the valve seat and valve face contacted
one another, the blueing will have been re-
moved.
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.
5-26
ENG
Valve seat width
Intake: 0.9 X 1.1 mm
<Limit>:1.6 mm
Exhaust: 0.9 X 1.1 mm
<Limit> 1.6 mm