1970-1973 Ski-Doo Snowmobiles Technical Data Manual, Page 36Get this manual
1971 MODELS Engine Type 300 Direct Timing (Advanced) inches B.T.D.C.150" .160" .140" .160" .140" .160" .140" .170" .150" .170" .180" .160" .180" .160" .180" .160" .190" .170" Indirect Timing (Advanced) inches B.T.D.C.205" .220" .148" .176" .195" .193" .241" .250" .171" .198" .221" .220"
335, 335E 399, 399E 640, 640E 292 340 440 775 250
.148".171" .180".201" .150".170"
1972 MODELS
ONE CYLINDER Engine Type 247247 292 302 337337 Direct .157" .010" .157" .010" .157" .010" .167" :t .010" Indirect .157" .010" .205" .010" .205" .010" .239" .010" Engine Type 343 401401 434434 435 640 641 775 TWO CYLINDERS Direct .147" .010" .147" .010" .147" .010" .147" .010" .167" .010" .167" .010" .177" .010" Indirect .169" .010" .156" .010" .156" .010" .156" .0 10" .186" .010" .179" .010" .190" .010"