3.11
Engine/Cooling/Exhaust
3
Crankshaft Runout Inspection
1. Support the crankshaft in a set of “V” blocks as shown.
2. Use a dial indicator to measure the runout at the
follow
ing locations:
• PTO end = First taper after bearing flat.
• MAG end = 1/2" from bearing flat.
3. Runout deflection cannot exceed .0025" (.07mm).
4. If the runout deflection exceeds the maximum
spe
cification, crankshaft trueing may correct the
deflection.
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
in
spected 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
cannot exceed the maximum clearance differential
specification.
Rotate the connecting rod on the crankshaft and feel for
a
ny 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.
Connecting Rod Side Clearance:
.0114"-.0295" (0.289-0.749mm)
Maximum Clearance Differential
.002" (0.051mm)
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