Arctic Cat Prowler HDX Service Manual page 50

Cleaning/Inspecting Piston Ring
Grooves
1. Take an old piston ring and snap it into two pieces;
then grind the end of the old ring to a 45° angle and
to a sharp edge.
2. Using the sharpened ring as a tool, clean carbon from
the ring grooves. Be sure to position the ring with its
tapered side up.
CAUTION
Improper cleaning of the ring grooves by the use of the
wrong type of ring groove cleaner will result in severe
damage to the piston.
Measuring Piston-Ring End Gap
(Installed)
1. Place each piston ring in the wear portion of the cyl-
inder. Use the piston to position each ring squarely in
the cylinder.
2. Using a feeler gauge, measure each piston-ring end
gap. Acceptable ring end gap must not exceed speci-
fications.
Measuring Piston Pin, Connecting
Rod Small End, and Piston-Pin Bore
1. Measure the piston pin outside diameter at each end
and in the center. If measurement does not meet
specifications, the piston pin must be replaced.
2. Inspect and measure the connecting rod small end
inside diameter. If the measurement exceeds specifi-
cations, the connecting rod must be replaced (see
Center Crankcase Components in this section).
3. Insert an inside dial indicator into the piston-pin
bore. Take two measurements to ensure accuracy.
The diameter must not exceed specifications. If the
diameter exceeds specifications, the piston must be
replaced.
Measuring Piston Skirt/
Cylinder Clearance
1. Measure the cylinder front to back in six places.
CC995
2. Measure the corresponding piston diameter at a point
8 mm (0.3 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 specifications.
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 illustration.
NOTE: Note the direction of the exhaust side of
the piston (5) for correct ring end gap orientation.
ATV-1070
ATV-1069
CC127D
47