The Hildebrand & Wolfmüller patent of 20 January 1894, No. 78553 describes a two-cylinder, four-stroke engine, with a bore and stroke of . It produced @ 240 rpm propelling a weight of up to a maximum speed of .The fuel-air mixture from the surface carburettor was regulated by a valve operated by controls on the handlebar. The engine, which was positioned flat in the frame, used hot tube ignition with the tube heater in front of the cylinder heads. The tube heater was ventilated by the lower downtubes while the upper downtubes held lubricating oil.