Abstract: A motorcycle transmission shifter assembly including a cam drum having at least two pins extending therefrom, and a shift mechanism engageable with the pins. The shift mechanism includes a tooth that is operable to engage a first one of the pins to rotate the drum in a first direction and a stop that is operable to engage a second one of the pins to prevent over-rotation of the drum in the first direction. Preferably, the shift mechanism includes a shift pawl and a shift lever and the stop is mounted on either the shift pawl or the shift lever. Additionally, the shift mechanism can include a second stop mounted on the other of the shift pawl or the shift lever, the second stop being operable to engage a third one of the pins to prevent over-rotation of the drum in a second direction.