Toro 500 EFI Service Manual page 85

2. Remove each ring by working it toward the dome of
the piston while rotating it out of the groove.

NOTE: If the existing rings will not be replaced with
new ones, note the location of each ring for proper
installation. When installing new rings, install as a
complete set only.
Measuring Piston-Ring End Gap
(Installed)
1. Place each compression ring in the wear portion of
the cylinder. 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 (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 speci-
fications, the piston pin must be replaced.
CC400D
2. Insert an inside dial indicator into the piston-pin
bore. The diameter must not exceed specifications.
Take two measurements to ensure accuracy.
Measuring Piston Skirt/Cylinder
Clearance
1. Measure the cylinder front to back in six places.
CC280D
2. Measure the corresponding piston diameter at the
recommended point above the piston skirt at a right
angle to the piston-pin bore. Subtract this measure-
ment from the measurement in step 1. The difference
(clearance) must not exceed 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.
ATV-1070
ATV-1069
CC127D
83