Automatic transmission for a motorcycle

Abstract

In order to reduce the influences of engine heat and vibration on a shift actuator, a shift actuator is disposed apart from the engine and the transmission on a vehicle. In particular a straddle-type vehicle, the vehicle includes a head pipe and a body frame including a main frame that extends rearward from the head pipe. The engine is suspended by the body frameand a transmission is disposed next to the engine. The transmission includes a shift mechanism having a multiple-step speed change gear and a clutch mechanism that interrupts the transmission of rotation at the switching of the speed change gear of the transmission. An automatic transmission control unit operates the clutch mechanism and switches the speed change gear of the transmission automatically. The automatic transmission control unit includes the shift actuator which is mounted to the body frame and is disposed opposite to the transmission with the body frame therebetween, as viewed from the side of the vehicle, for operating the shift mechanism. A shift rod joins together the shift mechanism and the shift actuator.