Main Bearing; Connecting Rod Lower Bearing; Piston Needle Bearing - Polaris IQ 2007 Service Manual

specification.
Bearing Interference Fit:
"
Carbureted = .001 -.002
" "
CFI = .0014 - .0024 (.061mm)

Main Bearing

Clean crankshaft thoroughly and oil main and connecting
rod bearings with Polaris engine oil. Carefully check each
main bearing on the crankshaft.
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 Lower Bearing

Measure connecting rod big end side clearance with a
feeler gauge on both sides of the connecting rod. The side
clearance on either side of the connecting rod cannot
exceed the connecting rod side clearance specification.
The difference between the two clearance measurements
= In. / mm.
.061mm)
"
(.026 -.051mm)
Engine and Cooling Systems
cannot exceed the maximum clearance differential
specification.
= In. / mm.
Connecting Rod Side Clearance:
" "
.0114 -.0295 (.289-.749mm)
Maximum Clearance Differential
"
.002 (.051mm)
Rotate the connecting rod on the crankshaft and feel for
any rough spots. Check radial end play in rod by
supporting rod against one thrust washer and alternately
applying up and down pressure. Replace bearing, pin, and
thrust washers if side clearance is excessive or if there is
any up and down movement detectable in the big end
bearing.

Piston Needle Bearing

1. Clean the end of the connecting rod and inspect inner bore
with a magnifying glass. Look for any surface
irregularities including pitting, wear, or dents.
2. Run a fingernail around the inside of the rod and check for
rough spots, galling, or wear.
3. Oil and install needle bearing and pin in connecting rod.
4. Rotate pin slowly and check for rough spots or any
resistance to movement.
5. Slide pin back and forth through bearing while rotating and
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