Engine
4-11
Valve and Valve seat inspection
Pour a good quality combustion chamber
cleaner into the intake and exhaust ports
(1). Look for leaks at the valve sealing
areas (2). There should be no leakage.
Inspect the valve face for pitting or wear.
If you have the proper tools, valve can be
ground. If not replacement will be
necessary.
Inspect the valve stems for mushroom
shape or a diameter larger than the body
of the stem.
Inspect the Valve seats for pitting or wear.
Measure the valve face width.
Service Wear Limit
2.0mm
Measure the stem to guide clearance.
Stem-to-guide clearance = valve guide
inside diameter – valve stem diameter
Service Wear Limit
Intake:0.08mm Exhaust:0.10mm
Measure the margin thickness. (a)
Margin thickness
Intake:2 mm
Exhaust:2.2 mm
Measure valve stem runout.
Runout limit 0.01 mm
Note:
When replacing a valve always replace
the valve guide and oil seal. Use
Lapping compound to mate the surface
between the face and valve seat.
Measure the valve seat surface width.
Service Wear Limit
2.0mm
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