1971-1973 Arctic Cat Snowmobiles Factory Service Manual, Page 120Get this manual
TRANSMISSION (STLAVVRENCE) General (StLawrence Drive Pulley)
A drive pulley (torque convertor) is power transmission mechanism which transmits power from the engine to driven pulleyThis transmission of power is accomplished by means of V-shaped beltThe variable pitch drive pulley has one (1) fixed face and one (1) moveable faceThe drive pulley m-oveable face is controlled by arms which change position in relation to the engine speed (RPM)When the engine is not in operation and when it is at slow idle, the distance between the fixed and moveable faces of the drive pulley is slightly greater than the width of the drive belt, resulting in "disengaging" relationship between the belt and drive pulleyAs the engine speed (RPM) increases, the arms are thrown outward by centrifugal force, causing the moveable face to move closer to the fixed faceAt this time, belt engagement occurs and power is transmitted to the driven pulleyRemove the captive bolt and locking washer