A motorcycle drive device includes a shiftable transmission set up to transmit drive power which can be provided by an engine crankshaft toward a drivable wheel. The transmission includes an input shaft having a rotation axis when is displaceable to adjust a spacing between the rotation axes of a primary gearwheel on the transmission input shaft and a primary pinion transferring the drive power from the crankshaft. A transmission input shaft bearing supporting the transmission input shaft is arranged in a bearing plate that is rotatable relative to a housing of the transmission. The bearing plate includes an adjusting mechanism arranged to change the position of the bearing plate with respect to the transmission housing to adjust the axial spacing of the rotation axes.