1978 Ski-Doo Shop Manual, Page 68Get this manual
SECTION 02 SUB-SECTION 07 (CHAINCASE) (Position lower sprocket with longer flange facing inside of case(For proper sprocket and chain use, see Technical Datal
REMOVAL
Remove pulley guard and drive beltRelease track tension and unbolt the end bearing housingUnbolt brake assemblyRemove tool box or battery (if applicable)Remove chaincase cover and drain oilPry oil seal from chaincaseRelease chain tension then remove cotter pin locking lower sprocketRemove spacerRemove bolts andor nuts securing chaincase to frameRemove aligning shirnts)Remove complete assembly from vehicle
Install the other spacer and new cotter pinProceed with pulley alignmentSecure chaincase to frameInstall chaincase flange oil sealA gap of approximately 1.6 mm (116") should exist between the end of chaincase flange and oil seal1.6mm approx
INSPECTION
Visually inspect chain for cracked, damaged or missing link rollersInspect for defective cone bearings, bearing cups, sprockets and oil retainer ringOil seal