Yamaha TDM850 1996 Service Manual page 142

VALVE AND VALVE SPRING
3. Eliminate:
S Carbon deposit
(from valve face)
4. Inspect:
S Valve face
Pitting/Wear ! Reface the face.
S Valve stem end
Mushroom shape or diameter larger than rest
of stem ! Replace.
5. Measure:
S Margin thickness a
Out of specification ! Replace.
6. Measure:
S Runout (valve stem)
Out of specification ! Replace.
NOTE:
S Always replace the guide if the valve is replaced.
S Always replace the oil seal if the valve is re-
moved.
7. Eliminate:
S Carbon deposit
(from valve face and valve seat)
8. Inspect:
S Valve seat
Pitting/Wear ! Reface valve seat.
9. Measure:
S Valve seat width a
Out of specification ! Reface valve seat.
4-18
ENG
Margin thickness:
0.8 X 1.2 mm
Runout limit:
0.01 mm
Valve seat width:
Intake: 0.9 X 1.1 mm
Exhaust: 0.9 X 1.1 mm