Yamaha WR426F(P), Owner'S Service Manual

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ENG
CYLINDER AND PISTON
Cylinder bore “C”
WR426F:
95.00 ~ 95.01 mm
(3.7402 ~ 3.7406 in)
WR400F:
92.00 ~ 92.01 mm
(3.6220 ~ 3.6224 in)
Taper limit “T” 0.05 mm (0.002 in)
Out of round “R” 0.05 mm (0.002 in)
“C” = Maximum D
“T” = (Maximum D
1
or D
2
)
– (Maximum D
5
or D
6
)
“R” = (Maximum D
1
, D
3
or D
5
)
– (Minimum D
2
, D
4
or D
6
)
●
If out of specification, replace the cylinder,
and replace the piston and piston rings as
set.
2nd step:
●
Measure the piston skirt diameter “P” with
a micrometer.
a
9 mm (0.35 in) from the piston bottom edge.
Piston size P
Standard
WR426F:
94.945 ~ 94.960 mm
(3.738 ~ 3.739 in)
WR400F:
91.945 ~ 91.960 mm
(3.6199 ~ 3.6205 in)
●
If out of specification, replace the piston
and piston rings as a set.