Appendix
36
b) Snap ring of piston pin
Jack the front end at the piston groove, to
clamp the other end with a nose plier, and
mount it in the groove while turning.
Make the opening of snap ring be away
from the notch of piston.
c) Connecting rod cover
Align connecting rod with the edge of the
connecting rod cover when assembling.
②
Piston inspection
Inspect the contact between the piston and cylinder, ring groove defect, top ablation and cracking, etc. If it
is seriously damaged, such as broken, it shall be replaced.
Remove carbon deposits
Carbon deposit is accumulated on the top of piston and the edge of upper port of the cylinder. Carbon
deposits shall be cleared up before the inspection. Soak the carbon deposit with kerosene first, and then
remove it with a blunt scraper or metal brush.
a) Outer diameter of piston skirt
Measure the outer diameter of the piston skirt by
outer diameter micrometer, to replace it if it exceeds
the service limit.
Standard
Service limit
81.962mm
81.86mm
b) The clearance between piston pin hole and piston pin
Use the inside micrometer and the outside micrometer to measure the inner diameter of the piston pin seat
hole and the outer diameter of the piston pin respectively. And then calculate its clearance value based on
measured result.
Alignment
mark
Snap ring of
piston pin
Notch
Alignment
mark