Yamaha YZ250 2022, Owner'S Service Manual

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CYLINDER HEAD, CYLINDER AND PISTON
5-6
EAM30086
REMOVING THE CYLINDER HEAD
1. Remove:
•
Cylinder head nut
TIP
Loosen each nut 1/2 of a turn at a time. After all
of the nuts are fully loosened, remove them.
EAM30543
REMOVING THE PUSH ROD
1. Remove:
•
Push rod bolt “1”
• Push rod “2”
NOTICE
ECA27140
Be sure to use the set pin. If the set pin is not
used, the power valve constituent parts will
result in damage.
TIP
• Set the set pin “3” included in owner’s tool kit to
remove the push rod bolt.
• Do not forget to remove the set pin.
2. Remove:
•
Set pin
EAM30544
REMOVING THE PISTON
1. Remove:
• Piston pin clip “1”
TIP
Before removing the piston pin clip, cover the
crankcase opening with a clean rag to prevent
the piston pin clip from falling into the crankcase.
2. Remove:
• Piston pin “1”
•
Piston “2”
• Small end bearing
NOTICE
ECA13810
Do not use a hammer to drive the piston pin
out.
TIP
Before removing the piston pin, deburr the pis-
ton pin clip’s groove and the piston’s pin bore ar-
ea. If both areas are deburred and the piston pin
is still difficult to remove, remove it with the pis-
ton pin puller set “3”.
3. Remove:
•
Piston ring
TIP
When removing a piston ring, open the end gap
with your fingers and lift the other side of the ring
over the piston crown.
Piston pin puller set
90890-01304
Piston pin puller
YU-01304
1
1
3
2
G088998