MOTORIZED BICYCLE.  Any vehicle having either two tandem wheels or one wheel in the front and two wheels in the rear, that is capable of being pedaled, and is equipped with a helper motor of not more than 50 cubic centimeters piston displacement which produces not more than one brake horsepower, and is capable of propelling the vehicle at a speed of no greater than 20 miles per hour on a level surface.  The terms do not include an electric bicycle.
(ORC 4511.01(H))