Checking The Valve Seats - Yamaha T135SE Service Manual

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Yamaha T135 Service Manual
VALVES AND VALVE SPRINGS
4-26
6. Measure:
9valve stem runout
Out of specification → Replace the valve.
NOTE:
9When installing a new valve, always replace
the valve guide.
9If the valve is removed or replaced, always
replace the valve stem seal.
Valve stem runout limit
0.01 mm (0.0004 in)
EAS00240

CHECKING THE VALVE SEATS

The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
9carbon deposits
(from the valve face and valve seat)
2. Check:
9valve seat
Pitting/wear → Replace the cylinder head.
3. Measure:
9valve seat width a
Out of specification → Replace the cylinder
head.
Valve seat width
Intake: 0.9 – 1.1 mm
(0.0354 – 0.0433 in)
Exhaust: 0.9 – 1.1 mm
(0.0354 – 0.0433 in)
<Limit>: 1.6 mm
MMMMMMMMMMMMMMMMMMMMMMMM
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.
ENG