Arctic Cat 2009 366 Service Manual page 42

Measuring Piston Skirt/
Cylinder Clearance
1. Measure the cylinder front to back in six places.
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 specifica-
tions.
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.
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3-16
ATV-1069
CC397D
ATV-1085B
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2. Install the compression rings (1 and 2) so the let-
ter(s) on the top surface of each ring faces the
dome of the piston. Rotate the rings until the ring
end gaps are on directly opposite sides of the pis-
ton according to the illustration.
NOTE: The chrome (silver) ring should be
installed in the top position.
! CAUTION
Incorrect installation of the piston rings will result in
engine damage.
CYLINDER/CYLINDER HEAD
ASSEMBLY
NOTE: If the cylinder/cylinder head assembly
cannot be trued, they must be replaced.
Cleaning/Inspecting Cylinder Head
! CAUTION
The cylinder head studs must be removed for this pro-
cedure.
1. Using a non-metallic carbon removal tool, remove
any carbon buildup from the combustion chamber
being careful not to nick, scrape, or damage the
combustion chamber or the sealing surface.
2. Inspect the spark plug hole for any damaged
threads. Repair damaged
"heli-coil" insert.
3. Place the cylinder head on the surface plate cov-
ered with #400 grit wet-or-dry sandpaper. Using
light pressure, move the cylinder head in a figure
eight motion. Inspect the sealing surface for any
indication of high spots. A high spot can be noted
by a bright metallic finish. Correct any high spots
before assembly by continuing to move the cylin-
der head in a figure eight motion until a uniform
bright metallic finish is attained.
! CAUTION
Water or parts-cleaning solvent must be used in con-
junction with the wet-or-dry sandpaper or damage to
the sealing surface may result.
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MD1343A
threads using a
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