Piston/Cylinder Clearance - Arctic Cat Cougar Service Manual

ENGINE
cleaning the grooves. If you damage the
grooves while cleaning, a new piston
must be installed.
7. Carefully remove all carbon buildup from the
ring grooves. Inspect the piston for missing,
broken or cracked ring lands. Inspect the grooves
carefully for cleanliness and for absence of burrs
or nicks. Recondition or replace the piston if
necessary.
8. Check the side clearance of each ring in its
groove by rolling the new ring around the piston
in its groove as shown in Figure 66. If the ring
grooves show excessive wear, install a new pis-
ton.
9. Inspect the condition of the piston crown.
Normal carbon buildup can be removed with a
®
@
177
wire brush or scraper. If the piston shows signs
of overheating, pitting or other abnormal condi-
tions, the engine may be experiencing preigni-
tion or detonation. Both conditions are discussed
in Chapter Two.
CAUTION
Do not clean piston skirts or ring lands
using a wire brush. The wire brush re-
moves aluminum, which will increase
piston clearance. The brush also rounds
the corners of the ring lands which re-
sults in decreased support for the piston
rings.
10. If the piston checked out okay after perform-
ing these inspection procedures, measure the
piston outside diameter as described under Pis-
ton/Cylinder Clearance in this chapter.
11. If new piston rings are required, the cylin-
ders should be honed before assembling the en-
gine. Refer to Cylinder Honing in this chapter.
Piston/Cylinder Clearance
The following procedure requires the use of
highly specialized and expensive measuring
tools. If such equipment is not readily available,
have the measurements performed by a dealer or
machine shop. Always replace all pistons as a set.
1. Measure the outside diameter of the piston
with a micrometer approximately 1 em (7 116
inch) above the bottom of the piston skirt, at a
90° angle to the piston pin (Figure 67).
2. Clean the cylinder block completely. Wash
the cylinder bore with soap and water to remove
oil and carbon particles. Clean the cylinder bore
thoroughly before attempting any measurement
to prevent inaccurate readings caused by foreign
matter.
3. Measure the cylinder bore with a bore gauge
or telescoping gauge (Figure 68). Then measure
the bore gauge or telescoping gauge with ami-
crometer to determine the bore diameter. Meas-
ure the cylinder bore at three vertical locations