Bearing Fit; Main Bearing; Connecting Rod (Big End) Bearing - Polaris 2007 Two Stroke Service Manual

MAINTENANCE
Make sure the thermostat opens and stays open!
Cycle the RPM from idle to enough RPM (3500) to
get coolant to flow but not enough RPM to engage
the clutch. This allows air to bleed from the rear
crossover tube. It is important to get enough coolant
flow to purge the air from the front close-off cooler
and observe this air reaching the bottle.
NOTE: Once the thermostat is open tip the
snowmobile slightly on its right side and cycle the
RPM from idle to enough RPM (4000) to get coolant
to flow but not enough RPM to engage the clutch.
Then tilt the machine slightly on its left side so that
the coolant bottle is the highest point in the cooling
system and cycle the RPM from idle to enough RPM
(4000) to get coolant to flow but not enough RPM to
engage the clutch.
WARNING
When performing the following checks and
adjustments, stay clear of all moving parts to avoid
serious personal injury. Never remove the pressure
cap when the engine is warm or hot. If the pressure
cap is to be removed, the engine must be cool.
Severe personal injury could result from stream or hot
liquid.

Bearing Fit

Any time crankshaft bearing failure occurs and the case is to be
reused, Polaris recommends checking the bearing fit into the
case halves using the following procedure.
With case halves cleaned, press a replacement bearing into each
of the main bearing journals to determine a basic amount of
press fit.
Do a comparison check of all journals by manually forcing the
bearing into the bearing seats noting if any are noticeably loose
3.8
or tight. Normal hand installation will be an indication of the
recommended interference fit. If the bearing falls out of the case
when the case is inverted, or if the crankcase bearing surface is
severely galled or damaged, the case should be replaced.
NOTE: Crankcase bearing interference fit is .001-
.002" (.026-.051mm).
Bearing Interference Fit: .001-.002" (.026-.051mm)

Main Bearing

Clean crankshaft thoroughly and oil main and connecting rod
bearings with Polaris engine oil. Carefully check each main
bearing on the shaft.
Due to extremely close tolerances, the bearings must be
inspected visually, and by feel. Look for signs of discoloration,
scoring or galling. Turn the outer race of each bearing. The
bearings should turn smoothly and quietly. The inner race of
each bearing should fit tightly on the crankshaft. The outer race
should be firm with minimal side to side movement and no
detectable up and down movement. Replace any loose or rough
bearings.

Connecting Rod (Big End) Bearing

Specialized equipment and a sound knowledge of crankshaft
repair and straightening is required to perform crankshaft work
safely and correctly. Crankshaft repair should be performed by
trained Polaris service technicians in a properly equipped shop.
= In. / mm.