Abstract: A power assist system for imparting an driving force to an operation cable operating a vehicle clutch mechanism is connected to the operation cable to define driving and driven portions of the operating cable. The power assist system comprises an outer casing, a motor having a drive shaft extending into the outer casing, a rotor stably mounted to the drive shaft, and a reel member mounted to the rotor for winding the drive and driven portions of the operation cable. The driving portion of the operation cable is connected to a clutch operation member of the vehicle. An ON-OFF switch is connected to the clutch operation member to control starting and stopping of the driving of the motor. When an operation force is applied to the drive portion of the operation cable through the clutch operation member, the ON-OFF switch activates the motor to cause the rotor to frictionally engage the reel member to impart a driving force to the operation cable to perform a clutching operation.

Abstract: The present invention relates to an improvement in the cooling efficiency of an air cooling and vent device for use with a belt drive type power transmission for an all terrain vehicle, wherein cooling air introduced into a belt drive casing by an air suction fan built integrally with a drive pulley of the transmission is forced out of an air outlet provided in the middle position between the drive pulley and a driven pulley to the atmosphere by the suction effect of a cooling fan of the engine.