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

Page: 268 / 596

4-25
ENG
CYLINDER HEAD, CYLINDER AND PISTON
EC474700
Combination of piston and cylinder
1. Check:
9 Cylinder mark
a
2. Check:
9 Piston mark
a
Piston clearance:
Standard <Limit>
0.045~0.050 mm 0.1 mm
(0.0018~0.0020 in) (0.004 in)
Cylinder mark
a a
Cylinder size
A
66.400~66.402 mm
(2.61417~2.61425 in)
B
66.404~66.406 mm
(2.61433~2.61441 in)
C
66.408~66.410 mm
(2.61449~2.61457 in)
D
66.412~66.414 mm
(2.61465~2.61472 in)
Piston mark
a a
(color) Piston size
A (red)
66.352~66.355 mm
(2.61228~2.61240 in)
B (orange)
66.356~66.359 mm
(2.61244~2.61256 in)
C (green)
66.360~66.363 mm
(2.61260~2.61272 in)
D (purple)
66.364~66.367 mm
(2.61276~2.61287 in)
EC474602
Piston clearance
1. Calculate:
9 Piston clearance
Out of limit
→
Replace piston, and piston
ring and/or cylinder.
Refer to “Cylinder” and “Piston”.
PISTON
CLEARANCE CYLINDER
BORE PISTON
DIAMETER
=
–
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