2010 Polaris Sportsman 850 Service Manual, Page 143Get this manual
ENGINE CrankshaftCam Chain Removal
1Remove crankshaft with cam chain and end seals
Crankshaft Inspection
1Visually inspect surface of crankshaft main and connecting rod journalsReplace crankshaft if any journal is scratched or pittedMeasure each main journal (A) and rod journal (B) in two locations, 90 degrees apartRecord measurements for bearing selection on page 5.47Calculate the difference between the two measurements for each journal to determine concentricity (C)Replace crankshaft if any journal is worn below the minimum diameter specification or if journal out-of-round exceeds maximum specificationACrankshaft Main Journal Diameter: 2.16422.1650" (54.97054.990 mm)Crankshaft Main Journal Concentricity: 0.00027" (0.007 mm) Out Of Round Cam ChainSprocket Inspection