HYOSUNG RX 125 Service Manual page 42

CAMSHAFT CAM WEAR
Worn-down cams are often the cause of mistimed
valve operation resulting in reduced output power.
The limit of cam wear is specified for both intake
and exhaust cams in terms of cam height �, which
is to be measured with a micrometer. Replace
camshafts if found it worn down to the limit.
Micrometer (25~50 mm) : 09900-20202
Can height
Height �
Intake cam
Exhaust cam
Inspect the camshaft and the camshaft bearing
wear, damage, or the oil hole is clogged.
CYLINDER HEAD DISTORTION
Decarbonate in combustion chamber.
Check the gasketed surface of the cylinder head for
distortion with a straightedge and thickness gauge, tak-
ing a clearance reading at several places as indicated. If
the largest reading at any position of the straightedge
exceeds the limit, replace the cylinder head.
Thickness gauge : 09900-20806
Cylinder head distortion
VALVE FACE WEAR
Measure the thickness � and, if the thickness is found
to have been reduced to the limit, replace the valve.
CAUTION
Visually inspect each valve for wear of its seating
face. Replace any valve with an abnormally worn face.
Valve face wear
VALVE STEM RUNOUT
Support the valve with "V" blocks, as shown, and check
its runout with a dial gauge. The valve must be replaced
if the runout exceeds the limit.
Valve stem runout
Service limit
34.18 mm
33.55 mm
Service limit 0.05 mm
Service limit 0.5 mm
Service limit 0.05 mm
ENGINE 3-12
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