Thank you to everyone who commented on the “Name That Motorcycle” photo on the HVA website and the HVA's Facebook page.
This bike is a 1959 Zimmerman, which was designed by the model builder Emil Zimmerman. It is believed to be one-of-a-kind and is housed in the Barber Vintage Motorsports Museum in Birmingham, Alabama. The most unusual characteristic of the Zimmerman is that its valve operation is controlled by a ported rotary sleeve and there are no conventional valves, springs or lifters. The bike was ridden in the Jack Pine Enduro and has been beautifully restored by Chuck Huneycutt, Barber's chief restoration mechanic.
And the winner of the contest is...Ben Thompson, from Lumberton, Texas!
For guessing correctly, Ben will receive a free HVA ballcap. The same cap is available here, in the online store.