1971-1973 Arctic Cat Snowmobiles Factory Service Manual, Page 41Get this manual
ENGINE SERVICING (TVVIN CYLINDER) 13If either the piston pin or needle bearing need replacement, replace as complete setInstall the open ends of the rings between the piston ring groove pinsInstall the needle bearings in the upper end of the connecting rodsPosition piston over the connecting rod with the arrow on top of piston pointing toward exhaust side of engine and secure with piston pin; retain in place with circlip on each end of the piston pinInsure the circlips are positioned in the piston pin grooves14
When cylinder is adequately installed, carefully remove the block from under the piston, insuring that the cyl inder base gasket is not damagedInsure each piston is installed correctlyProper installation is obtained when the arrow on top of the piston points toward the exhaust side of the engineInstall new head gasketsgasket sealerNOTE: DO NOT use