Installing The Piston And Piston Rings; Installing The Crankshaft And Piston - Yamaha 25BMH Service Manual

POWR
CRANKSHAFT AND CYLINDER BODY
INSTALLING THE PISTON AND
PISTON RINGS
Install:
• 2nd piston ring
• Top piston ring
CAUTION:
• Install the piston ring with the T mark
facing up.
• Align each piston ring end gap with its
respective locating pin.
• After installing the piston rings, check
that they move smoothly.
NOTE:
Apply Yamaha 2-stroke motor oil on the pis-
ton ring and piston ring groove.
INSTALLING THE CRANKSHAFT AND
PISTON
1. Install:
• Small-end bearing
Needles per piston
34 pieces
Small-end bearing installer
90890-06527
2. Install:
• Piston
Installing steps
(1) Assemble the washer
to the crankshaft.
(2) Push out the small-end bearing installer
with piston pin.
(3) Install circlip.
CAUTION:
Install the piston with "UP" mark on the
piston crown facing towards the flywheel
side.
NOTE:
Apply Yamaha 2-stroke motor oil on the
small-end bearing and piston pin.
5-39
E
a
and the piston