HYOSUNG MS3 250 Sercie Manual page 69

▣ ▣ 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
service limit, replace the pin with a new one.
Piston
pin
18.980 mm
diameter
(0.7472 in)
Micrometer(0~25 mm) : 09900-20201
▣ ▣ PISTON RING FREE END GAP INSPE-
CTION
Before installing piston rings, measure the free end
gap of each ring using vernier calipers. If the gap is
less than the service limit, replace the ring.
Piston ring
free end gap
1st 8.0 mm (0.315 in)
2nd
6.8 mm (0.268 in)
Vernier calipers : 09900-20101
▣ ▣ PISTON RING END GAP INSPECTION
(Assembly condition)
Insert the piston ring squarely into the cylinder using
the piston head.
Measure the end gap with a thickness gauge.
If the gap exceeds the service limit, replace the pis-
ton ring with a new one.
Piston ring
end gap
(Assembly
condition)
0.10 ~ 0.30 mm
1st
(0.004 ~ 0.012 in)
0.35 ~ 0.50 mm
2nd
(0.014 ~ 0.020 in)
Piston ring end gap(Assembly condition)
1st
2nd
Thickness gauge : 0990-20806
Service limit
14.980 mm
(0.5898 in)
Service limit
5.7 mm (0.224 in)
4.6 mm (0.181 in)
Standard
0.20 ~ 0.32 mm
(0.008 ~ 0.013 in)
0.20 ~ 0.32 mm
(0.008 ~ 0.013 in)
Service limit
0.5 mm (0.020 in)
0.5 mm (0.020 in)
ENGINE 3-26