1910 Cycle and Motorcycle Exhibition
Neat arrangement of the Royal Enfield control levers, with closed wires.
Enfield new two-speed lightweight, showing the countershaft gear and operating lever.
The Enfield Cycle Co., Ltd.
Redditch. Stand No. 75.
The Enfield motor-bicycle has had a very good season, the little Kharki twin being frequently met on the roads. A still better season is anticipated in 1911, and one or two material alterations are introduced. Firstly, the power has been increased, the bore and stroke being now respectively 54 and 75 millimeters, the present-day popularity of the long stroke being fallen in with. A more radical departure consists in the adoption of chain drive, but without dispensing with the pedalling gear. This is accomplished in the following fashion A sprocket wheel is mounted on the engine shaft by means of a friction clutch, which allows for a certain amount of give to the engine impulses. On the end of the bottom bracket are two chain wheels, a large and a small one. The first is coupled up to the engine sprocket, and the second to a sprocket on the road wheel by endless chains. The magneto is arranged behind the bottom bracket and is driven by a shaft, which passes through the foot of the diagonal tube, which is forked for the purpose.
The cylinders are arranged at 60 degrees to one another, and the valves, all of which are mechanically operated, are arranged at the back and the front of the cylinders instead of between them. The front fork is mounted on parallel links, the top links being extended to carry one end of an anti-vibratory spring, the other end of which is fixed to the cross bar of the fork above the tyre. Inverted levers are fitted to the steering handles. The Bowden wires connected to these, as well as to the carburetter control levers, are enclosed within the handlebar tubes, and issue from an aperture below the lamp bracket, which is formed in one with the lug on the top of the handlebar stem. In addition to the front rim brake a pedal brake operates on a dummy rim fixed to the back wheel on the two-speed machine. An ingenious and convenient idea consists in fitting all the connections to the tank at one side so that the tank can be easily withdrawn from its position in the frame towards that side.
Royal Enfield Two-speed Gearbox
The two-speed gear used on the Enfield (English) motorcycle is of the same pattern and is clearly outlined at Fig. 184. Either gear ratio may be brought in action by expanding the hardened steel bands A into one of the drums B, also of hardened steel, to which the chain wheels C are secured. The change in gear ratio is obtained in the same manner as in the Phelon & Moore by driving through the large sprocket for low speed and through the smaller sprocket for high speed. The expanding bands A are carried on internal drums D which take the drive, and which are keyed on the ball bearing shaft E that is employed to drive the sprocket F that connects with the rear hub. The clutches are engaged by cams cut into the block G, which is capable of sliding in either direction according to which gear is desired. The action of the cam is to force one of the pegs H against the split roller I, which forces open the band A until it engages with B, which is rotated by the engine. The object of splitting the roller I is to permit the clutch to pick up smoothly. The block G which contains the cam is moved by the rack J and the pinion K, which is operated by a vertical shaft and lever at the top of the crank. Three pairs of cams numbered 1, 2, and 3 are cut in G, each of these being .005 inch higher than the one preceding it. Should the band A wear to such a point that cam A is not sufficiently high to operate it, the member G may be turned around so the next larger cam will be used to expand the brake band. The practical application of this gear to a Clement (French) motorcycle is clearly outlined at Fig.185.
Motorcycles Sidecars and Cyclecars, 1914, by Victor Page
