HYOSUNG GF125 Service Manual page 52

PISTON DIAMETER
Using a micrometer, measure the piston outside diameter
at the place 15㎜ from the skirt end as shown in Fig. If
the measurement is less than the limit, replace the pis-
ton.
09900-20203
Service limit
Piston oversize
NOTE:
U s i n g a s o f t - m e t a l s c r a p e r , d e c a r b o n t h e
crown of the piston. Clean the ring grooves
similarly.
PISTON-CYLINDER CLEARANCE
As a result of the above measurement, if the piston to
cylinder clearance exceeds the limit shown in the table
below, overhaul the cylinder and use an oversize piston,
or replace both cylinder and piston.
Service limit
PISTON RING-GROOVE CLEARANCE
Using a thickness gauge, measure the side clearance of
the 1st and 2nd rings. If any of the clearances exceeds
the limit, replace both piston and piston rings.
09900-20803
Piston ring-groove clearance
Piston ring
1st
2nd
Micrometer(50~75㎜)
56.880㎜
0.5, 1.0㎜
0.120㎜
Thickness gauge
Service limit
0.180㎜
0.150㎜
SERVICING ENGINE 3-18
15㎜