Cylinder And Piston Troubleshooting; Piston & Cylinder Datas - PGO G-MAX 50 Service Manual

(4)Cylinder and piston:
A. Troubleshooting.
a. compression pressure is too low, difficult to start engine and running unsmoothly.
1. Cylinder head gasket cracked.
2. Spark plug is not well-locked.
3. Piston ring worn out or cracked.
4. Cylinder, piston worn out.
5. Reed valve is defective.
b. compression pressure is too high, engine overheating or abnormal noise.
1.piston tip has too much carbon piled up.
c. Abnormal piston noise
1. cylinder and piston worn out.
2. Piston pin hole or piston pin worn out.
3. Connecting rod small-end or bearing worn out.
d. Abnormal piston or cylinder noise
1.piston ring worn out or cracked.
2.Cylinder worn out or cracked.
B. The operation notice:
1.clean before operation to avoid particles dropping into engine.
2.The connect surface of gasket must be clean.
3.Dismantle the cylinder and the cylinder head by screw driver.
Do not scratch the contact surface.
4.Cylinder inner surface and piston outer surface can't be scratched.
The contact surface should be lubricated by specified oil.
C. PISTON & CYLINDER DATAS:
Part name/description
Cylinder head Flatness
cylinder Bore
Piston/ Clearance b/w Piston
Piston ring ring piston and
Piston outer diameter
Measuring location of piston outer dia.
(12mm from the lower end of skirt)
Clearance b/w piston and cylinder
Piston pin hole inner dia
Piston pin hole inner diameter
Piston pin outer diamerer
Clearance between piston and piston pin
Connecting rod small end inner dia
Standard Value
39.995~40.015
Lst ring
nd
2 ring
39.950~39.970
0.045~0.065
13.022~13.013
10.002~10.008
9.994~10.000
0.004~0.018
13.996~14.007
(mm)
0.05~0.06
0.05~0.06
Limit of use
(mm)
0.100
40.050
0.10
0.10
39.895
0.10
13.045
10.025
9.970
0.030
14.025