1980 Ski-Doo Shop Manual, Page 44Get this manual

SECTION 03 SUB-SECTION 02 (ENGINES)
Measuring distance betweencrankshaft blades

Oil seal pushAr no 420 977 920

c) Subtract measurement from measurement minus toleranceTotal balance IS distance to be shimmedShim(s) must be located between magneto side beanng and crankshaft blade

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives