Arctic Cat Sno Pro 120 2013 Service Manual page 19

CYLINDER/CYLINDER HEAD
 NOTE: If the cylinder/cylinder head assembly cannot
be trued, they must be replaced.
Cleaning/Inspecting Cylinder Head
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 threads using a "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.
Cleaning/Inspecting/Measuring
Cylinder Distortion
1. Wash the cylinder in parts-cleaning solvent.
2. Check the gasket surface of the cylinder for distor-
tion with a straightedge and thickness gauge tak-
ing a clearance reading at several places. If the
largest reading at any position of the straightedge
exceeds the limit, replace the cylinder.
3. Maximum cylinder distortion must not exceed
0.004".
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ATV-1069
4. Inspect the cylinder for pitting, scoring, scuffing,
warpage, and corrosion. If marks are found, repair
the surface using the Ball Hone (see Honing Cyl-
inder sub-section).
5. Place the cylinder on the surface plate covered
with #400 grit wet-or-dry sandpaper. Using light
pressure, move the cylinder in a figure eight
motion. Inspect the sealing surface for any indica-
tion 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 in a figure eight motion until a uniform bright
metallic finish is attained.
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.
Honing Cylinder
1. Wash the cylinder in parts-cleaning solvent.
2. Inspect the cylinder for pitting, scoring, scuffing,
and corrosion. If marks are found, repair the sur-
face using the Ball Hone.
 NOTE: To produce the proper 45° crosshatch pattern,
maintain a low drill RPM. If honing oil is not available,
use a lightweight, petroleum-based oil. Thoroughly
clean the cylinders after honing using detergent soap
and hot water and dry with compressed air; then imme-
diately apply oil to the cylinder bores. If a bore is
severely damaged or gouged, the cylinder must be
replaced.
3. If any cylinder bore measurement exceeds the
limit, hone the cylinder and install an oversized
piston or replace the cylinder.
MEASURING CONNECTING ROD
SMALL END BORE INSIDE DIAMETER
1. Using a small bore gauge, measure the connecting
rod small end bore inside diameter.
2. Measurement must be within 0.6301-0.6307".
CAUTION
IO087