He could be sentenced to 1 to 3 years behid bars.
The victim Kevin Royston lost his leg in the accident.
For six months he didn't even know had struck him and left him for dad at the side of the road.
Tips led police to Stenzel.
Prosecutors say he struck the cycle with his 1968 Corvette stingray then fled the scene. They say paint from the car matched paint taken from the bike after the collision.
Stenzel has had two previous DWI's.
Prosecutors established Stenzel was at a bar in Geneva on the date of the collision, but they could not establish whether he consumed alcohol.