HYOSUNG 2010 ST7 Service Manual page 75

PISTON-TO-CYLINDER
CLEARANCE
To determine the piston-to-cylinder clearance, calculate
the difference between the cylinder bore and outside
diameter of the piston.
Standard
Piston-to-cylin-
0.045~0.075 mm
der clearance
(0.0018~0.0030 in)
PISTON PIN HOLE BORE
Using a dial calipers, measure the piston pin hole bore
both the vertical and horizontal directions.
If the measurement exceeds the service limit, replace
the piston.
Piston pin hole bore
Dial calipers : 09900-20605
PISTON PIN DIAMETER
INSPECTION
Using a micrometer, measure the piston pin outside
diameter at three position, both the ends and the center.
If any of the measurements is founds less than the ser-
vice limit, replace the pin.
Piston pin diameter
Micrometer(0~25 mm) : 09900-20201
PISTON RING FREE END
GAP INSPECTION
Before installing piston rings, measure the free end gap
of each ring using a vernier calipers. If the gap is less
than the service limit, replace the ring.
Piston ring free end gap
1st
2nd
Piston ring free end gap
1st
2nd
Vernier calipers : 09900-20101
Service limit
0.120 mm
(0.0047 in)
Service limit
20.030 mm (0.7886 in)
Service limit
19.980 mm (0.7866 in)
Standard
Approx. 9.9 mm (0.390 in)
Approx. 10.5 mm (0.413 in)
Service limit
7.9 mm (0.311 in)
8.4 mm (0.330 in)
ENGINE 3-28