Bucking Bar The Bucking Bar helps engage and disengage 2-stroke 48cc and 66/80cc motorized bicycle engine kits in conjunction with the clutch actuator bearing Installation is simple: remove the drive sprocket case cover and in the center of the drive sprocket will be the bucking bar. Remove that stock bucking bar, install this new bucking bar, close the case, and you're good to go Note: Be sure the clutch actuator bearing is within the motor before installing, as the motor will not engage or disengage without both parts