Suzuki GP125 - Page 47

3-15
Decarbon the piston and piston ring grooves, as
shown in Fig. After cleaning the grooves, fit the
rings and rotate them in their respective grooves
to be sure that they move smoothly
Carbon in the groove is liable to cause the piston
ring to get stuck in the groove, and this condi
tion will lead to reduced engine power output.
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A piston whose sliding surface is badly grooved
or scuffed due to overheating must be replaced.
Shallow grooves or minor scuff can be removed
by grinding with emery paper of about #400.
PISTON RINGS
Check each ring for end gap, reading the gap
with a thickness gauge, as shown in Fig. If the
end gap is found to exceed the limit, indicated
below, replace it with a new one.
The end gap of each ring is to be measured with
the ring fitted squarely into the cylinder bore
and held at the least worn part near the cylinder
bottom, as shown in Fig
Service limit 0.80 mm (0.031 in)
As the piston ring wears, its end gap increases
reducing engine power output because of the
resultant blowby through the enlarged gap. Here
lies the importance of using piston rings with
end gaps within the limit.
Measure the piston ring free end gap to check
the spring tension.
| Service limit 6.0 mm (0.24 in)