kymco mo gd125 150 Manuales De Servicio

• The cylinder and piston can be serviced with the engine installed in the frame.
• When installing the cylinder, use a new cylinder gasket and make sure that the dowel pins are

correctly installed.

• After disassembly, clean the removed parts and dry them with compressed air before inspection.

Standard (mm)

Service Limit (mm)

Item

SH30DA

SH25DA

SH30DA SH25DA

I.D.

57.405_

57.

415

52.400_

52.

410

57.50

52.50

Warpage

0.01

0.01

0.05

0.05

Cylindricity

0.01

0.01

0.05

0.05

True roundness

0.01

0.01

0.05

0.05

Ring-to-groove

top

0.015_

0.05

0

0.015_

0.05

0

0.09

0.09

clearance

Second

0.015_

0.05

0

0.015_

0.05

0

0.09

0.09

top

0.15_

0.30 0.15_

0.30

0.50

0.50

 Piston,

Ring end gap

Second

0.15_

0.30 0.15_

0.30

0.50

0.50

 piston ring

Oil side rail

0.2_

0.9

0.2_

0.9

æ

æ

Piston O.D.

57.375_

57.

395

52.370_

52.

390

57.30

52.30

Piston O.D. measuring position

9mm from

bottom of skirt

9mm from

bottom of skirt

9mm from

bottom of

skirt

9mm from

bottom of skirt

.

Piston-to-cylinder clearance

0.010_

0.04

0

0.010_

0.04

0

0.01

0.01

Piston pin hole I.D.

15.002_

15.

008

15.002_

15.

008

15.04

15.04

Piston pin O.D

14.994_

15.

000

14.994_

15.

000

14.96

14.96

Piston-to-piston pin clearance

0.002_

0.01

4

0.002_

0.01

4

0.02

0.02

Connecting rod small end I.D. bore

15.016_

15.

034

15.016_

15.

034

15.06

15.06

• When hard starting or poor performance at low speed occurs, check the crankcase breather for

white smoke.  If white smoke is found, it means that the piston rings are worn, stuck or broken.

• Worn or damaged cylinder and piston rings

• Worn or damaged piston rings

• Worn, stuck or broken piston rings

• Worn or damaged cylinder and piston

• Excessive carbon build-up in combustion

• Worn cylinder, piston and piston rings

chamber or on piston head

• Worn piston pin hole and piston pin

• Incorrectly installed piston

Cylinder