Arctic Cat 400 Service Manual page 80

Measuring Piston Pin (Outside
Diameter) and Piston-Pin Bore
1. Measure the piston pin outside diameter at each
end and in the center. If measurement is not
within specifications, the piston pin must be
replaced.
2. Insert an inside dial indicator into the piston-pin
bore. The diameter must not exceed specifica-
tions. Take two measurements to ensure accu-
racy.
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CC995
ATV-1070
ATV-1069
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Measuring Piston Skirt/
Cylinder Clearance
1. Measure the cylinder front to back in six places.
2. Measure the corresponding piston diameter at a
point 15 mm (0.6 in.) above the piston skirt at a
right angle to the piston-pin bore. Subtract this
measurement from the measurement in step 1.
The difference (clearance) must be within speci-
fications.
Installing Piston Rings
1. Install ring expander (4) in the bottom groove of
the piston; then install the thin oil rings (3) over
the expander making sure the expander ends do
not overlap. Stagger the end gaps of the upper
and lower thin oil rings according to the illustra-
tion.
NOTE: Note the direction of the exhaust side of
the piston (5) for correct ring end gap orientation.
2. Install the compression rings (1 and 2) so the let-
ter on the top surface of each ring faces the
dome of the piston. Rotate the rings until the
ring end gaps are on directly opposite sides of
the piston (see illustration).
NOTE: The chrome (silver) ring should be
installed in the top position.
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CD325
ATV-1085B
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