1902 Duesenburg. Yup, not the car, but by the car maker before he turned to automotive manufacturing

Before earning legendary status in Indy car racing and creating the mighty Duesenberg Model J motorcar in 1928, Fred Duesenberg created a motorcycle in 1902 that featured a unique rotary valve. Only one was produced before his attention turned to the new automotive industry.

Via: http://thenewcaferacersociety.blogspot.com/2009/01/its-duesy.html