1980 Ski-Doo Shop Manual, Page 152Get this manual
SECTION 03 SUB-SECTION 03, (IGNITION TIMING)
IGNITION TIMINGTWO CYLINDER ENGINES (377, 444, 464, 503, 640 TYPES)
Two methods are detailed in this section; the first using the timing marks stamped on the engine, the second using Top Dead Center gauge
Retar?ed
pOSition
TIMING MARKS PROCEDURE
1Disconnect spark plug wires and remove spark plugs2Remove rewind starter assembly from engine then remove the fan protector, starting pulley and "V" belt
NaTE: The upper breaker point controls the timing of the magneto side piston and the lower breaker point controls the P,T,Oside piston3Rotate crankshaft until breaker points, visible through magneto ring opening, are fully openedAdjust points setting to 0.35 mm 0.05 (.014" .002) using feeler gauge and screwdriver, as illustratedRepeat procedure for other pointAdjust both sides equallyFull
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