HYOSUNG 2010 ST7 Service Manual page 71

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
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
CAMSHAFT JOURNAL WEAR
Determine whether or not each journal is worn down to
the limit by measuring the oil clearance with the
camshaft installed in place.
Use the plastigauge to read the clearance at the
widest portion, which is specified as follows :
Camshaft journal
oil clearance
(IN & EX)
TAPPET & SHIM WEAR
When measuring the valve clearance, the clearance
should be within the standard range.
Valve clearance
Intake valve
Exhaust valve
, which is to be
Service limit
34.98 mm (1.377 in)
33.08 mm (1.302 in)
Service limit
0.15 mm (0.006 in)
Standard (When cold)
0.1 ~ 0.2 mm
(0.004 ~ 0.008 in)
0.28 ~ 0.32 mm
(0.011 ~ 0.013 in)
(T.D.C)
(B.T.D.C)
Intake open
(A.B.D.C)
Intake close
(B.D.C)
Valve timing diagram
ENGINE 3-24
(A.T.D.C)
Exhaust close
(B.B.D.C)
Exhaust
open