1979 Ski-Doo Supplementary Shop Manual, Page 113Get this manual
SECTION 04 SUB-SECTION 04 (I GN IT ION TIMING)
C.DIGNITION354-454 ENGINE TYPES
FOREWORD
On models equ ipped with C.Dignition system, plug firing is initiated by an electrical pu lse This pulse is released when metal projection on the flywheel hub rotates near the pick-up co ilTherefore, timing must be performed wh ile the engine is runningA stroboscopic timing light such as Sun PTL 45, SnapOn MT215B, Bosch EFAW 169A, or su itab le equiva lentplus 12 vo lt battery are neededW ith the piston posit ioned at 1.40 mm (055") B.T .D.C magneto ring mark should al ign with ce ntral mark on crankcase (around timing hole)
IGNITION IMING
Timing procedu re for this eng in type is composed of four main phases, all being equally impo rtant: 1Position of the armature plate2Position of the timing marks on magneto ring 3A ir gap between trigger coil and magneto ring4Timing verification using stroboscopic timing light1To obtain best generator coil performance, position the armature plate on the crankcase with the reta ining cap screws in the midd le of the plate slots