Yamaha YZ250 Owner's Service Manual page 120

INSTALLING THE PISTON RING AND
PISTON
1. Install:
• Piston ring "1"
• Take care not to scratch the piston or damage
the piston ring.
• Align the piston ring gap with the pin "2".
• After installing the piston ring, check the
smooth movement of it.
2. Install:
• Gasket (cylinder) "1"
• Small end bearing "2"
• Dowel pin "3"
• Apply the engine oil onto the bearing (crank-
shaft and connecting rod) and connecting rod
big end washers.
• Install the gasket with the seal print side to-
ward the crankcase.
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CYLINDER HEAD, CYLINDER AND PISTON
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3. Install:
• Piston "1"
• Piston pin "2"
• Piston pin clip "3"
• The arrow "a" on the piston dome must point
to exhaust side.
• Before installing the piston pin clip, cover the
crankcase with a clean rag to prevent the pis-
ton pin clip from falling into the crankcase cav-
ity.
• Apply the engine oil on the piston pin.
Do not allow the clip open ends to meet the
piston pin slot "b".
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