Removing The Piston; Checking The Cylinder And Piston - Yamaha YP250R 2005 Service Manual

CYLINDER AND PISTON
EAS00253

REMOVING THE PISTON

1. Remove:
• piston pin clips 1
• piston pin 2
• piston 3
CAUTION:
Do not use a hammer to drive the piston
pin out.
NOTE:
• Before removing the piston pin clip, cover the
crankcase opening with a clean rag to pre-
vent the piston pin clip from falling into the
crankcase.
• Before removing the piston pin, deburr the
piston pin clip groove and the piston pin bore
area. If both areas are deburred and the pis-
ton pin is still difficult to remove, remove it
with the piston pin puller set 4.
Piston pin puller set
2. Remove:
• top ring
• 2nd ring
• oil ring
NOTE:
When removing a piston ring, open the end
gap with your fingers and lift the other side of
the ring over the piston crown.
EAS00259

CHECKING THE CYLINDER AND PISTON

1. Check:
• piston wall
• cylinder wall
Vertical scratches → Rebore or replace the
cylinder, and replace the piston and piston
rings as a set.
5 - 30
ENG
90890-01304