1978 Ski-Doo Shop Manual, Page 151Get this manual
SECTION 04 SUB-SECTION 02 (ENGINES)
CLEANING
Discard all gasketsClean all metal components in non-ferrous metal cleanerScrape off carbon formation from cylinder exhaust port, cylinder head and piston dome using wooden spatula
Circlip break
NOTE: The letters "AUS" (over an arrow on the piston dome) must be visible after cleaning
Piston notch
Clean the piston ring grooves with groove cleaner tool, or with piece of broken ring
NOTE: To prevent leakage, install exhaust manifold prior to cylinder head tightening
DISASSEMBLYASSEMBLY