Yamaha YZ250(W)/W1, Owner'S Service Manual

Page: 276 / 596

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CYLINDER HEAD, CYLINDER AND PISTON
ENG
7. Install:
9 O-ring
1
9 Side holder
2
9 Screw (side holder)
3
9 YPVS breather hose
4
NOTE:
9 Apply the lithium soap base grease on the O-
rings.
9 Install the side holder with its projection
a
facing upward.
8. Install:
9
Gasket (power valve cover)
1
9 Power valve cover
2
9 Screw (power valve cover)
3
NOTE:
9 Install the gasket with its cut
a
facing down-
ward and the seal print side toward the power
valve cover.
9 Install the power valve cover so that the arrow
mark
b
faces upward.
EC475233
Piston ring and piston
1. Install:
9
Piston ring
1
NOTE:
9
Take care not to scratch the piston or damage
the piston ring.
9 Align the piston ring gap with the pin
2
.
9 After installing the piston ring, check the
smooth movement of it.
2. Install:
9
Gasket (cylinder)
1
9 Small end bearing
2
9 Dowel pin
3
NOTE:
9 Apply the engine oil onto the bearing (crank-
shaft and connecting rod) and connecting rod
big end washers.
9 Install the gasket with the seal print side toward
the crankcase.
4 Nm (0.4 m•kg, 2.9 ft•lb)
4 Nm (0.4 m•kg, 2.9 ft•lb)
1P8-9-32-4b 4/6/06 2:12 PM Page 4