Precautions In Operation; Troubleshooting - Sym PA12B Service Manual

8. Cylinder / Piston

Precautions in Operation

General Information
The engine must be removed from the frame before the repairing of the cylinder and the
piston.
Specification
Subject
Cylinder Inside Diameter
Warpage
Cylinder
Taper
Out of round
Piston Ring/
Groove Clearance Second Ring
Piston Ring End
Gap
Piston/
Piston Ring
Piston Ring
Thickness
Piston Outside Diameter
Piston Outside Diameter
Measure Point
Piston/ Cylinder Clearance
Piston Pin Hole Inside Diameter
Piston Pin Outside Diameter
Piston/ Piston Pin Clearance
Connecting Rod Small End Inside Diameter

Troubleshooting

Low Compression or Instability
Worn cylinder or piston rings
Over High Compression
Excessive carbon built-up on the piston or
combustion chamber
Knocking or Abnormal Noise
Worn piston or cylinder
Excessive carbon built-up on the top of the
piston
Worn Piston Pin and Piston Pin Hole
8-2
To this chapter contents
56.000~56.010
Top Ring
Top Ring
Second Ring
Oil Ring
Top Ring
Second Ring
55.970~55.990
10mm up from the bottom of the piston
15.002~15.008
14.994~15.000
15.010~15.028
Excessive Smoke
Worn cylinder or piston or piston rings
Improper piston rings installation
Overheating
Excessive carbon built-up on the top of the
piston
Measurement unit：mm
Specification
Standard
－
－
－
0.025~0.055
0.015~0.045
0.150~0.350
0.150~0.350
0.200~0.500
1.475~1.490
1.475~1.490
0.020~0.050
0.002~0.014
Service Limit
56.100
0.050
0.050
0.050
0.130
0.120
0.500
0.500
－
1.460
1.460
55.8700
0.110
15.050
14.850
0.020
15.070