Yamaha XV19SX(C), Service Manual, Page: 292 / 494

VALVES AND VALVE SPRINGS
5-43
2. Replace:
• Valve guide
NOTE:
To ease valve guide removal and installation,
and to maintain the correct fit, heat the cylinder
head to 100 °C (212 °F) in an oven.
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a. Remove the valve guide with the valve guide
remover “1”.
b. Install the new valve guide with the valve
guide installer “2” and valve guide remover
“1”.
c. After installing the valve guide, bore the valve
guide with the valve guide reamer “3” to ob-
tain the proper valve-stem-to-valve-guide
clearance.
NOTE:
After replacing the valve guide, reface the valve
seat.
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3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
• Valve face
Pitting/wear
→
Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than the
body of the valve stem
→
Replace the valve.
5. Measure:
• Valve margin thickness D “a”
Out of specification
→
Replace the valve.
Valve guide remover (ø6)
90890-04064
Valve guide remover (6.0 mm)
YM-04064-A
Valve guide installer (ø6)
90890-04065
Valve guide installer (6.0 mm)
YM-04065-A
Valve guide reamer (ø6)
90890-04066
Valve guide reamer (6.0 mm)
YM-04066
Valve margin thickness D (intake)
1.15–1.45 mm (0.0453–0.0571 in)
Limit
0.4 mm (0.02 in)
Valve margin thickness D (ex-
haust)
1.15–1.45 mm (0.0453–0.0571 in)
Limit
0.4 mm (0.02 in)