Yamaha TT-R125(W), Owner'S Service Manual

Page: 318 / 616

4 - 27
ENG
VALVES AND VALVE SPRINGS
3. Inspect:
●
Valve face
Pitting/wear
→
Grind the face.
●
Valve stem end
Mushroom shape or diameter larger
than the body of the stem
→
Replace.
4. Measure:
●
Margin thickness
a
Out of specification
→
Replace.
5. Measure:
●
Runout (valve stem)
Out of specification
→
Replace.
NOTE:
●
When installing a new valve always replace
the guide.
●
If the valve is removed or replaced always
replace the oil seal.
Margin thickness:
Intake:
0.4 ~ 0.8 mm
(0.0157 ~ 0.0315 in)
Exhaust:
0.8 ~ 1.2 mm
(0.0315 ~ 0.0472 in)
Runout limit:
0.01 mm (0.0004 in)
6. Eliminate:
●
Carbon deposits
(from the valve face and valve seat)
7. Inspect:
●
Valve seats
Pitting/wear
→
Reface the valve seat.