1978 Ski-Doo Shop Manual, Page 175Get this manual
SECTION 04 SUB-SECTION 02, (ENGINES)
" Place clean cloth over crankcase to prevent
circlips from falling into crankcase then use pointed tool to remove circlips from pistonDrive the gudgeon pins in or out using suitable drive punch .and hammer, CAUTION: When tapping gudgeon pin in or outof piston, hold piston firmly in place to eliminate the possibilities of transmitting shock and pressure to the connecting rodAt assembly ,place the pistons over the connecting rods with the letters AUS (over an arrow on the piston dome) facing direction of the exhaust port