Checking The Valve Seats - Yamaha XF50W 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:
•
2. Check:
• valve seat
3. Measure:
• valve seat width a
Out of specification
der head.
TTTTTTTTTTTTTTTTTTTTTTT
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.
Measure the valve seat width.
d.
NOTE:
Where the valve seat and valve face contacted
one another, the blueing will have been removed.
• • • • • • • • • • • • • • • • • • • • • • •
4. Lap:
8valve face
8valve 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
carbon deposits
(from the valve face and valve seat)
Pitting/wear -* Replace the cylinder head.
-* Replace the cylin-
Valve seat width
Intake: 0.9 ~ 1.1 mm (0.0354 ~
0.0433 in)
<Limit>: 1.6 mm(0.063 in)
Exhaust: 0.9 ~1.1 mm
(0.0354~0.0433 in)
<Limit>: 1.6 mm(0.063 in)