NOTE: Arrow on top of Kimpex pistons should point toward the exhaust sides of the engine (except on polaris pistons, where the arrow points toward the magneto side) KIMPEX SNOWMOBILE PISTONS High performance, long life - engineered to provide the best possible path for combustion chamber heat transfer to cylinder walls. PISTON KIT INCLUDES: PISTON, RINGS, PINS AND CIRCLIPS. All pistons, rings, pins and circlips are manufactured to O.E.M. specifications. All individual components will interchange with original parts. CYLINDER PREPARATION - CAST IRON LINERS * Measure cylinder for taper and out-of-roundness. Any measured difference of more than .003" (smallest cylinder diameter to largest) would indicate re-boring is necessary. * Hone good condition cylinder with #220 or 300 grit stones to re-glaze. A 60 degree cross-hatch pattern is the recommended finish to insure proper ring sealing. CYLINDER PREPARATION - CHROME, NIKASIL OR ELECTROFUSION LINERS * Measure cylinder for taper and out-of-roundness These models cannot be re-bored if a measured difference of more than .003"exists between smallest and largest cylinder diameter, the cylinder must be replaced or sleeved with a cast iron liner. Hone good condition cylinder with #500 grit stones. PORT OPENING PREPARATION * To prevent ring breakage, all horizontal port edges must be chamfeered until a minimum 3/64" radius is produced. The best method is to pull strips of emery cloth through the ports or use a round file.