1980 Ski-Doo Shop Manual, Page 12Get this manual
SECTION 01 (TOOLS)
Polyamld ring pusher 277 engine MAG 420 273 930 PTO 420 273 940
To install polyamld ring in crankcase
277 engine
Crankshaft feeler gauge503 engine MAG 420 876 625 PTO 420 876 620 Mag side: All 503 engines up to no.3 181 891 and engines no3 181 921 to 3181937PTO: All 503 engines