KD  |  1907-09  |  UK  :

The British KD was assembled between late 1907 and 1909 by Leo Ripault and Co. of Poland Street, Oxford Street, London. The device was a bicycle attachment that fitted within the main frame to drive the rear wheel by belt, tensioned by a jockey pulley. It differed from the original French version in that it had front suspension which preceded the Earles variety by several decades. Two engine sizes were available at 1½ hp and 2 hp. The make was listed for two years.

The engine, tank, jockey pulley and associated components formed a complete set that could be attached to an ordinary roadster bicycle, held to the frame by three clips. The principal engineering novelty was the valve arrangement, in which the inlet valve worked automatically and was surrounded by the mechanically-operated exhaust valve, the two being concentric with a single valve seat in the centre of the cylinder head. The silencer consisted of a perforated casing surrounding the valve seating, and an extra exhaust port was provided at the bottom of the cylinder. The exhaust valve lifter was brought into action by retarding the spark lever to its fullest limit. The carburettor had no float chamber and was controlled by a petrol valve regulating the flow of petrol rather than the quantity of air. The motor attachment including engine, tank and jockey pulley weighed approximately 30 lb. Two brakes were provided, one acting against the belt rim and the opposite shoe against the wheel rim, and a second brake acting on the engine flywheel. Battery ignition was employed and the total weight of the complete machine was approximately 75 lb.

The two engine sizes were the 1¼ hp with a bore and stroke of 60x60mm and the 1¾ hp with 65x65mm dimensions. An excellent spring fork was also supplied with the KD, its spring hidden from view and protected from dust within the upper portion of the device, suitable for fitting to any standard roadster bicycle.

Leo Ripault and Co. manufactured Oleo spark plugs from 1902 and went on to produce electrical equipment for the automotive and aviation industries over the following decades, remaining active in 1963 with some 1,300 employees. Ripault was also involved in aviation, associated with the Petre monoplane of 1910