Polaris 2007 Sportsman 450 EFI, Service Manual

Page: 94 / 406

3.36
ENGINE
Crankcase Bearing Inspection
1. Remove the seal from the PTO side crankcase.
2. Inspect the crankshaft main bearings, balancer shaft
bearings, and pump shaft bearing.
NOTE: Due to extremely close tolerances and minimal
wear, the bearings must be inspected visually, and by
feel. Look for signs of discoloration, scoring or galling.
Turn the inner race of each bearing. The bearings should
turn smoothly and quietly. The outer race of each bearing
should fit tightly in the crankcase. The inner race should
be firm with minimal side to side movement and no
detectable up and down movement.
3. Support the crankcase and drive or press the main bearings
out of each crankcase.
4. To remove balancer shaft bearings and pump shaft bearing
use a blind hole bearing puller.
NOTE: Bearings are stressed during the removal
process and should not be re-used!
Pump Shaft Oil Seal/Water Pump Mechanical
Seal Removal (Engine Disassembled)
NOTE: The water pump mechanical seal can be
removed without removing the engine. Refer to Water
Pump Mechanical Seal Installation.
Replace the pump shaft seal and water pump mechanical
seal whenever the crankcase is disassembled.
1. Remove the pump shaft bearing from the Magneto (right
hand) side crankcase.
2. Pry out the oil seal, noting the direction of installation with
the spring side facing IN (toward inside of case).
3. Drive the water pump mechanical seal out of the crankcase
from inside to outside. Note: The new mechanical seal must
be installed after the crankcases are assembled, using a
special tool. See Mechanical Seal Installation.
Crankcase Inspection
1. Remove all traces of gasket sealer from the crankcase
mating surfaces. Inspect the surfaces closely for nicks,
burrs or damage.
2. Check the oil pump and oil passage mating surfaces to be
sure they are clean and not damaged.