1978 Ski-Doo Shop Manual, Page 53Get this manual
SECTION 02 SUB-SECTION 04 (DRIVEN PULLEY)
DISASSEMBLYASSEMBLY
01n order to measure driven pulley spring tension, the pulley halves must be separatedTo do this, insert length of 18" diarod between the halvesCheck tension using fish scale positioned 90 with pulley axle(Refer to Technical Data for correct spring tension)
INSTALLATION
With drive chain tension released, hold upper sprocket and chain in position then insert assembled driven pulley shaft through chaincase and sprocketInstall spring washer and castellated nutTighten castellated nut fully then back off nut 116 of turnLock in position with new cotter pin_ CAUTION: It is important that nut is backed off or damage may occur due to burnt or seized bearingApply chain tensionPosition chaincase cover and replenish with chaincase oilInstall brake assembly and tool box or batteryInstall carburetor and air silencer boxConnect driven pulley support to steering upper columnInstall drive belt and pulley guard