3-34 ENGINE
VALVE STEM AND VALVE FACE WEAR CONDITION
• Visually inspect each valve stem and valve face for wear and
pitting. If it is worn or damaged, replace the valve with a new
one.
VALVE STEM DEFLECTION
• Lift the valve about 10 mm (0.39 in) from the valve seat.
• Measure the valve stem deflection in two directions, perpen-
dicular to each other, by positioning the dial gauge as shown.
• If the deflection measured exceeds the limit, then determine
whether the valve or the guide should be replaced with a new
one.
Valve stem deflection (IN. & EX.):
Service Limit: 0.25 mm (0.010 in)
09900-20607: Dial gauge (1/100 mm)
09900-20701: Magnetic stand
VALVE STEM WEAR
• If the valve stem is worn down to the limit, as measured with a
micrometer, replace the valve.
• If the stem is within the limit, then replace the guide.
• After replacing valve or guide, be sure to recheck the deflec-
tion.
Valve stem O.D.:
Standard (IN.) : 4.475 – 4.490 mm (0.1762 – 0.1768 in)
(EX.) : 4.455 – 4.470 mm (0.1754 – 0.1760 in)
09900-20205: Micrometer (0 – 25 mm)
NOTE:
If valve guides have to be removed for replacement after
inspecting related parts, carry out the steps shown in valve
guide servicing. (3-35)
SAMPLE
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