Crankshaft / Cam Chain Removal; Cam Chain / Sprocket Inspection; Crankcase Inspection (Lower); Crankshaft Inspection - Polaris Sportsman 850 Service Manual

CRANKSHAFT / CAM CHAIN REMOVAL

1. Remove crankshaft with cam chain and end seals.

CAM CHAIN / SPROCKET INSPECTION

1. Cam chain should be replaced if damage is evident
or if sprockets show visible signs of wear. Inspect
drive and driven sprockets.

CRANKCASE INSPECTION (LOWER)

1. Remove main bearing inserts from lower crankcase
half. Replace crankcase assembly if a bearing bore
is galled or if bearing inserts have rotated in the
case.

CRANKSHAFT INSPECTION

1. Visually inspect surface of crankshaft main and
connecting rod journals. Replace crankshaft if any
journal is scratched or pitted.
ENGINE / COOLING SYSTEM
2. Measure each main journal (A) and rod journal (B) in
two locations, 90 degrees
measurements for bearing selection on page 5.49,
page 3.62. Calculate 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 specification.
MEASUREMENT
A - Crankshaft Main Journal Diameter:
2.1642 - 2.1650" (54.970 - 54.990 mm)
C - Crankshaft Main Journal Concentricity:
< 0.00027" (0.007 mm) Out Of Round
B - Connecting Rod Journal Diameter:
1.7718 - 1.7726" (45.005 - 45.025 mm)
C - Connecting Rod Journal Concentricity:
< 0.00027" (0.007 mm) Out Of Round
D - Maximum Runout:
.001" (.025 mm)
3. Support crankshaft on V-blocks or on-centers in a
crankshaft stand or lathe. Measure crankshaft runout
(D) and replace if runout exceeds specification
above.

CONNECTING ROD INSPECTION

1. Secure connecting rod lightly in a soft jawed vise.
apart. Record
3
3.59