Sym FIDDLE 125 Service Manual page 83

SYM
PISTON REMOVAL
Plug crankcase opening with a cleaning cloth
to prevent from piston pin snap ring or other
parts falling into crankcase when
disassembling.
Hold another snap ring with pliers.
Push out the piston pin from the side that not
removed the snap ring.
Remove piston rings.
Caution
Pay attention to remove piston rings
because they are fragile.
Disassemble the piston rings.
Check if the piston rings are damaged or its
grooves are worn.
Cleaning the carbon in piston ring grooves.
Install the piston rings and then measure
clearance between piston ring and its
grooves.
Service Limit: Top ring: replace if over
0.09mm
2nd ring: replace if over
0.09mm
Take out the piston rings and place them
respective into cylinder below 20mm of
cylinder top. Measure each piston ring
gaps.
Caution
Push the piston rings into cylinder with
piston top-end in parallel motion.
Service Limit: Top ring: replace if over
0.50mm
2nd ring: replace if over
0.650mm
7. CYLINDER/PISTON
Piston ring
Piston
Feeler gauge
piston ring
Push in
Feeler gauge
7-5