Arctic Cat Sno Pro 120 Service Manual page 250

4. With the armature removed from the magnet hous-
ing, remove snap ring (D) from the armature.
Account for shim (E) and locking plate (F).
5. Using a flat-blade screwdriver, carefully remove the
seal from the bearing housing.
CLEANING AND INSPECTING
1. Thoroughly clean all components except the arma-
ture and brushes in parts-cleaning solvent; then dry
with compressed air.
CAUTION
Do not wash the armature and brushes in any kind of
solvent. Use only compressed air and clean dry, lint-
free cloth in cleaning these components.
2. Inspect all threaded areas for damaged or stripped
threads.
3. Inspect the brush holder assembly and brushes for
damage or wear. Using a caliper, measure the length
of the brushes. If brush measurement is less than
0.40 in., replace with new brushes and brush springs
as a set.
4. Inspect brush leads for cracks, wear, or fraying. If
any of these conditions exist, replace with new
brushes along with new brush springs as a set.
5. Inspect the rear cover bushing for wear.
6. Inspect the front cover bearing for wear.
5-16
7. Inspect the brass commutator end of the armature for
any discolored spots or damage. If the commutator is
slightly discolored or damaged, the armature must be
replaced. This is a molded commutator and no
attempt to turn it down in a lathe should be
attempted.
Do not use emery cloth to clean the commutator as
emery particles will become imbedded in the brass
commutator resulting in a short circuit. Use only #200
grit sandpaper.
8. Inspect the commutator end of the armature for
ZJ141A
buildup in the grooves. Carefully remove any
buildup by undercutting using a thinly ground hack-
saw blade. Do not cut any deeper than the original
groove which can be seen by looking at the end of
the commutator.
9. Using a caliper, measure the undercut. Maximum
undercut groove must be 0.008 in.
ZJ142A
Buildup in the grooves must be removed to prevent
any chance of an electrical arc between individual sec-
tions of the commutator.
10. Inspect the commutator for shorting using a multim-
eter and the following procedure.
A. Set the selector to the OHMS position.
B. Touch the black lead to the armature shaft.
C. Using the red tester lead, probe the commutator
end of the armature. The meter indicator should
not change. If the indicator shows resistance, the
armature is shorted and must be replaced.
11. Inspect the armature for shorting using a "growler"
and the following procedure.
A. Place the armature in the "growler."
B. While holding a metal strip on the armature,
rotate the armature an entire revolution. If the
metal strip vibrates at any point on the armature,
the armature is shorted and must be replaced.
CAUTION
CAUTION
SNO2171