Yamaha XV19SX(C) Service Manual page 292

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.
M MMM M MMM M M MMM M M MMM M
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".
M MMM M M MMM M MMM
5-43
VALVES AND VALVE SPRINGS
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.
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
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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 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)
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