Precautions In Operation; Troubleshooting - Sym HD2 125 Service Manual

8. CYLINDER / PISTON

Precautions in Operation

General Information
Both cylinder and piston service cannot be carried out when engine mounted on frame.
Specification Unit：mm
LC12W & LC18W
ID ( LC18W not included)
Cylinder
Bend
Clearance between piston
rings
Ring-end gap
Piston/
Piston ring
OD of piston ( LA18W not included)
Clearance between piston and cylinder
ID of piston pin boss
OD of piston pin
Clearance between piston and piston pin
ID of connecting rod small-end
LC18W
Cylinder ID
Piston OD of piston

Troubleshooting

Low or Unstable Compression Pressure
Cylinder or piston ring worn out
Knock or Noise
Cylinder or piston ring worn out
Carbon deposits on cylinder head top-side
Piston pin hole and piston pin wear out
8-2
To this chapter contents
Item
Top ring
nd
2 ring
Top ring
nd
2 ring
Oil ring side rail
Item
Standard
56.995~57.015
-
0.015~0.050
0.015~0.050
0.150~0.300
0.300~0.450
0.200~0.700
56.985~57.005
0.010~0.040
15.002~15.008
14.960~15.000
0.002~0.014
15.016~15.034
Standard
60.995~61.015
60.985~61.005
Smoking in Exhaust Pipe
Piston or piston ring worn out
Piston ring installation improperly
Cylinder or piston damage
Engine Overheat
Carbon deposits on cylinder head top side
Cooling pipe clogged or not enough in coolant
flow
Limit
57.016
0.050
0.090
0.090
0.500
0.650
-
56.900
0.100
15.040
14.930
0.020
15.060
Limit
61.016
60.900