1970-1979 Ski-Doo Snowmobiles Service Manual, Page 127Get this manual
CHAPTER SEVEN Pressure Lever and Roller Round Shaft Type Drive Pulley RemovalInstallation
CAUTION
Do not pry belt off over pulleys or belt andor pulleys may be damaged
1Remove drive belt2To hold engine while removing retaining bolt, perform the following: aRemove spark plug(s)bRotate crankshaft until piston (PTO piston for twin cylinder engines) is approximately in(25mm) BTDCcInsert length of rope such as recoil starter rope into spark plug hole (Figure 3)dSlowly rotate crankshaft counterclockwise until piston bears against rope3Make sure alignment marks on pulley halves are visibleIf not, make new marks4Apply pressure to governor cup of pulley and remove retaining bolt (Figure 4)NOTE: Pulley is spring loaded and may spring apart if pressure is not applied during bolt removal