Generic Onyx 50, Service Manual

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ID 39.995-40.015 40.05
Curvature - 0.05
Cylindricity 0.006 0.05
Flatness 0.03 0.05
Cylinder
Circular degree - 0.05
first ring
0.015
－
0.05
0.09
Clearance between piston ring and
ring groove
second
ring
0.015
－
0.05 0.09
first ring 0.1-0.25 0.5
Clearance of the mouth of piston ring
second
ring
0.1-0.25 0.5
OD of piston 39.97-39.99 39.9
Clearance between piston and cylinder 0.005-0.015 0.1
Piston
ring
ID of piston pin hole 12.002-12.008 12.04
OD of piston pin 11.994-12 11.96
Clearance between piston pin hole and piston pin 0.002-0.014 0.02
ID of wrist-pin end of connecting rod 14.016-14.034 14.06
14.2 Failure diagnosis
Low compression pressure white smoke from the vent pipe
wear, burning or snap in the piston wear and damage in the piston ring
wear or damage in the cylinder or the piston wear and damage in the piston or the cylinder
damaged gasket
，
gas leak between the crankcase and the gas
Higher compression pressure abnormal sound from the piston
Excessive carbon deposit in the damage in the cylinder, the piston or
combustion chamber the piston ring
14.3 Cylinder body
14.3.1 Removal of cylinder body
Remove cylinder body after removing cylinder cap.
Cylinder body