HYOSUNG TE 450 Service Manual page 68

▣ ▣ VALVE SPRING
The force of the coil spring keeps the valve seat tight.
A weakened spring results in reduced engine power
output and often accounts for the chattering noise
coming from the valve mechanism.
Check the valve springs for proper strength by mea-
suring their free length and also by the force required
to compress them. If the spring length is less than
the service limit or if the force required to compress
the valve spring is not within specification, replace
both the inner and outer springs as a set.
Valve spring free length
Inner
Outer
Vernier calipers : 09900-20101
Valve spring tension
Inner
Outer
▣ ▣ CAMSHAFT
The camshaft should be checked for runout and also
for wear of cams and journals if the engine has been
noted to produce abnormal noise or vibration or a
lack of out-put power. Any of these abnormality could
be caused by a worn camshaft.
▣ ▣ CAMSHAFT 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.
Cam height � �
Intake cam
Exhaust cam
Micrometer(25~50 mm) : 09900-20202
Service limit
36.9 mm (1.45 in)
39.9 mm (1.57 in)
Standard
6.5 ~ 7.1 kgf
(14.3 ~ 15.7 lbs)
at length 32.0 mm (1.26 in)
12.0 ~ 14.0 kgf
(26.5 ~ 30.9 lbs)
at length 35.5 mm (1.40 in)
Service limit
39.88 mm (1.570 in)
39.88 mm (1.570 in)
ENGINE 3-26
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