HYOSUNG GF125 Service Manual page 47

3-13 SERVICING ENGINE
VALVE HEAD RADIAL RUNOUT
Place the dial gauge at right angles to the valve head,
and measure the valve head radial runout. If it measures
more than limit, replace the valve.
Service limit
VALVE GUIDE-VALVE STEM
CLEARANCE
Measure the clearance in two directions, "X" and "Y" ,
perpendicular to each other, by rigging up the dial gauge
as shown. If the clearance measured exceeds the limit
specified below, then determine whether the valve or the
guide should be replaced to reduce the clearance to with-
in the standard range:
Standard
0.010~0.037㎜
IN.
0.030~0.057㎜
EX.
VALVE STEM WEAR
If the valve stem is worn down to the limit, when mea-
sured with a micrometer, and the clearance is found to
be in excess of the limit previously indicated, replace the
valve, if the stem is within the limit, then replace the
guige. After replacing valve or guide, be sure to recheck
the clearance.
09900-20205
Valve stem O.D.
IN.
EX.
VALVE STEM CONDITION
Inspect the valve stem end face for pitting and wear. If
pitting or wear of the stem end face are present, the
valve stem end may be resurfaced, providing that the
length ① will not be reduced to less than 3.8㎜. If this
length becomes less than 3.8㎜, the valve must be
replaced. After installing a valve whose stem end has
been ground off as above. check to ensure that the face
② of the valve stem end is above the cotters ③.
0.03㎜
Service limit
0.35㎜
0.35㎜
Micrometer(0~25㎜)
Standard
4.975~4.990㎜
4.955~4.970㎜