Tracker Off-Road 500S Service Manual page 55

3. Inspect the perimeter of each piston for signs of
"blowby" indicated by dark discoloration. "Blowby"
is caused by worn piston rings, excessive carbon in
ring grooves, or an out-of-round cylinder.
Removing Piston Rings
1. Starting with the top ring, slide one end of the ring
out of the ring-groove.
CC400D
2. Remove each ring by working it toward the top of
the piston while rotating it out of the groove.
NOTE: When installing new rings, install as a com-

plete set only.
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.
FI711
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.
ATV-1070
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.
ATV-1069
Measuring Piston Skirt/Cylinder
Clearance
1. Measure the cylinder front to back in six places.
CC127D
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 larger measurement in step 1. The differ-
ence (clearance) must be within specifications.
53