1999 Ski-Doo Factory Shop Manual Volume One, Page 247Get this manual
Section 06 ELECTRICAL Subsection 02 (IGNITION TIMING)
DUCATI CDI SYSTEM
377 and 503 Engine Types on Formula SSL Proper ignition timing is determined by trigger coil positionIf for any reason, ignition timing accuracy is suspected, it can be verified as follows
Verifying Magneto Flywheel Timing Mark Position
Prior to checking the timing, it may be necessary to verify the position of the timing mark on the magneto flywheel, for the following reasons: 1To detect missing or broken magneto flywheel Woodruff key which would allow change of timing to occur, with eventual break down of the engine2To correctly locate and mark timing mark on new service magneto flywheel3To verify the correct location of the factory timing mark4To detect wrong magneto flywheel corresponding to different engine typeTo verify the position of the timing mark on the magneto flywheel, proceed as follows: 1Clean the area around the spark plugs, and remove them2Remove the rewind starter from the engine3Install the TDC gauge in the spark plug hole, (magnetogenerator side) and adjust as follows: aPosition the magneto flywheel at approximately TDC