Polaris 2001 High-Performance Snowmobile Service Manual (PN 9916690), Page 105Get this manual
ENGINE Cylinder Service
Maximum engine performance and easy starting are directly related to the compression of the fuel and air mixture in the combustion chamberIt is important that the cylinder walls are concentric, smooth and perpendicular to the crankshaft center lineAll new engines have these characteristics built into them, however, the stresses and heat of operation may cause the bore to distort or score, resulting in loss of compression and power
Inspection
A simple way of checking cylinderpiston condition is to remove the exhaust manifold and look into the exhaust portIf there is considerable amount of blow by (brown or black carbon deposit) under the piston rings, the cylinder should be removed and honedThe piston rings should be replaced alsoThe cylinder should always be inspected whenever an engine has been disassembled for repair or any time loss of power or cylinder cranking compression is notedA visual inspection after the cylinder head is removed will reveal if the cylinder should be removed for honingInspect for any scratches or signs of scoring or brown areas which indicate ring leakage and distortion