1985 Ski-Doo snowmobile Service Manual, Page 263Get this manual
Section 03 TRANSMISSION Sub-section 03 (DRIVE PULLEY)
INSTALLA TION
Clean crankshaft extension using fine steel wool and clean cloth CAUTION: When installing drive pulley on engiT nereference mark on inner halfouter half and governor cup must be in line
4,10, Innerouter half
Lock crankshaft in position as explained in removal procedureMake sure crankshaft is rotated 45 counterclockwise from TDCposition and that cylinder is completely filled with starter rope or use crankshaft locking toolInstall inner half on crankshaft extension then postion outer half assembly on fixed half square shaft,CAUTION: Be careful when installing outer half assembly on square shaft of drive pulley to avoid scratches on "Duralon" bushing caused by square shaft edge