Yamaha MAJESTY YP250, Service Manual

Page: 118 / 267

4-22
CYLINDER AND PISTON
ENG
NOTE:
NOTE:
NOTE:
YP******
PISTON AND PISTON RINGS REMOVAL
1. Remove:
S
Piston pin circlip 1
S
Piston pin 2
S
Piston 3
Before removing the piston pin circlip, cover the
crankcase opening with a clean towel or rag to
prevent the circlip from falling into the crank-
case cavity.
2. Remove:
S
Top ring
S
2nd ring
S
Oil ring
When removing the piston ring, open the end
gap of the ring by fingers, and push up the other
side of the ring.
YP402100
CYLINDER INSPECTION
1. Measure:
S
Cylinder bore
Out of specification
Rebore or replace
D
Measure the cylinder bore with a cylinder
bore gauge.
D
Measure the cylinder bore in parallel to and at
right angles to the crankshaft. Then, find the
average of the measurements.
Cylinder bore:
69.000 69.005 mm
<Limit: 69.1 mm>
<Defferance limit between A, B
and C:
0.03 mm>
2. Measure:
S
Warpage
Out of specification
Replace.
Cylinder warpage limit:
0.03 mm