3-28 ENGINE
• Remove the oil seal
9
and spring seat
0
.
• Remove the other valves in the same manner as described
previously.
CYLINDER HEAD DISTORTION
• Decarbonize the combustion chambers.
• Check the gasket surface of the cylinder head for distortion.
Use a straightedge and thickness gauge. Take clearance
readings at several places.
• If readings exceeds the service limit, replace the cylinder
head.
Cylinder head distortion:
Service Limit: 0.10 mm (0.004 in)
09900-20803: Thickness gauge
VALVE FACE WEAR
• Visually inspect each valve face for wear. Replace any valve
with an abnormally worn face.
• The thickness of the valve face decreases as the face wears.
Measure the valve head
T
. If it is out of specification replace
the valve with a new one.
Valve head thickness
T
:
Service Limit: 0.5 mm (0.02 in)
09900-20101: Venier calipers (150 mm)
VALVE STEM RUNOUT
• Support the valve using V blocks and check its runout using
the dial gauge as shown.
• If the runout exceeds the service limit, replace the valve.
Valve stem runout:
Service Limit: 0.05 mm (0.002 in)
09900-20607: Dial gauge
09900-20701: Dial gauge chuck
09900-21304: V blocks