1974 Ski-Doo Shop Manual, Page 132Get this manual
C.DIGNITION
FOREWORD
On models equipped with C.Dignition system, plug firing is initiated by an electrical pulseThis pulse is released when metal projection on the flywheel hub ro tates past the pick-up coilTherefore, timing must be performed while the engine is runningA stroboscopic timing light such as Sun PTL 45, SnapOn MT215B, Bosch EFAW 169A, or suitable equivalentplus 12 volt battery are needed
Warning: Ensure that no one will pass behind the vehicule, even momentarily, while timing engineAlso, make sure that pulley guard is in position and that track is clear of tools, clothes, etcStart engine The magneto ringcrankcase timing marks should coincide when full advance is obtainedFull advance is at 5,000 RPMCaution: Running the engine unnecessarily will cause premature slider shoe wearIf the timing marks do not coincide, remove rewind starter and starting pulleySlacken off the two (2) Allen capscrews securing the armature plate Rotate plate clockwise if timing is advanced, counter-clockwise if timing is retarded