Arctic Cat 650 Twin2004, Service Manual

Page: 51 / 210

3-22
Cleaning/Inspecting Piston Rings
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.
Measuring Piston-Ring End Gap
(Installed)
1. Place each piston 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 be within
specifications.
CC280D
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.
ATV-1070
2. Insert an inside dial indicator into the piston-pin
bore. The diameter must not exceed specifications.
Take two measurements to ensure accuracy.
ATV-1069
Measuring Piston Skirt/
Cylinder Clearance
1. Measure the cylinder front to back in six places.
CC397D
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
specifications.
Installing Piston Rings
1. Install a thin oil ring (3), ring expander (4), and
thin oil ring (3) in the bottom groove of the piston.
Stagger the end gaps of the upper and lower thin
oil rings according to the illustration. An F is
stamped on the piston to indicate front.
! 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.