Yamaha TT-R125EY Service Manual page 120

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