Two enthusiastic motorcycles, Messrs. W. Rankin and R. Player of the Wrights Forge and Engineering Co., Ltd., from Tipton, Staffordshire, patented a machine gun carriage that could be hand carried, or double as a sidecar on a motorcycle. To attach to a motorcycle, one wheel was detached, revealing a socket that connected to the sidecar port of a motorcycle and two other anchor points were stored in a box below the axle. The handle for hand-carrying it detached and operated as a support for the seat of the machine gun operator when used as a sidecar. A prototype was built and attached to a Royal Enfield 6hp, for which nothing was impossible. It does not appear to have been adopted by the armed forces.
The special features of this excellent machine are given prominent attention. They are the result of long and careful experiment.
The manufacturers of this machine, the Enfield Cycle Co., Ltd., Hunt End, Redditch, have keenly followed the motor bicycle question, and although experimenting with various types last season, did not definitely decide on their design until the last Stanley Show.
The illustration on the next page gives a general idea of the arrangement of engine, tank, carburetter, transmission, etc., but there are several details which require special description, and by the courtesy of the makers, we are enabled to also give illustrations of some of the important details.
The engine, as will be noticed, is of an extremely robust form, and is provided with ample wearing surfaces. The power at full speed is 1.75 h.p.; the timing gear wheels are enclosed in a special outside case, and both axles have good long bearings, with phosphor bronze bushes.
The contact breaker plate has a bush fitting over an extension of the aluminum crank chamber; this bush is of large diameter, and about 0.75 inch wide. There is, therefore, no chance of the plate developing side play through wear, and upsetting the accuracy of the adjustment between cam and spring.
Large valves are fitted to both exhaust and inlet, the exhaust pipe being especially large and strong, terminating under bottom bracket, where a silencer of ample dimensions is firmly bolted to the bridge of the bicycle frame.
In our illustration of the inlet valve, the arrangement for testing whether valve is free is clearly shown.
The stalk of the valve extends through the dome, and as the body of the inlet valve is provided with a special casting with two seats, air cannot be drawn in through the top of the dome. This small fitting is very useful, and often saves a great deal of time; the joint is not disturbed, and consequently lasts much longer than it otherwise would do.
The exhaust valve is fitted with a very certain, but simple, lifter, and as the lever operating it is attached on the right handlebar, and the switch on the left, the whole command of the machine is in the rider's hands, without leaving go of the handles.
The carburetter is quite automatic, and is entirely governed by the adjustable milled top of stalk A, referring to the illustration in the section; stalk marked A terminates in needle point with a screw adjustment. This has to be opened from a quarter to half a turn; the petrol flows along the passage marked B, and rises to the needle valve, which is under the stalk marked D.
The height of the lift of this valve is set when the machine leaves the factory, and need not be disturbed when running; a supply of more or less petrol will govern the carburation, and when the best position is found, a letter O is marked on the top of A when open, and the letter S when shut, these letters being opposite the needle or indicator between the two milled tops.
The tank to which the carburetter is attached contains on gallon of petrol, and a compartment for induction coil and accumulator.
The frame is specially made throughout, and has been designed purposely for a motor bicycle. Special thick gauge tubing is used everywhere, and the wheel base has been considerably lengthened. The front forks are of a most substantial prttern, being made D section, and of great strength. The crown is the same as the one used on the Royal Enfield tricycle for the last 18 months, and which has given entire satisfaction.
The brakes are two in number; both are hand brakes, one acting on the back wheel, and the other on the front. It was deemed advisable to fit two brakes, as running down a steep hill with the valve lifter raised, one brake was not found sufficient to arrest the machine suddenly, but with a gentle application of both, this machine can be stopped in a few yards in cases of emergency.
The makers claim that by fitting the motor in front of the head, not on the handle-bar, but bolted to the frame itself, they obtain the maximum of air for cooling purposes, which is undoubtedly correct; at the same time the motor is well out of the dirt. The belt drive differs from the majority of machines which we have seen, being V section, and run crossed instead of open. By means of the long drive, the belt can be run slacker without slipping, and the crossing causes it to encircle the small driving of the head.
There are undoubted advantages to having the motor in front, and it ensures a more even distribution of weight.
We have had one of these machines for some weeks and have verified it runs very well. It is certainly the most satisfactory 1.5 h.p. we have come across. The placement of the levers and taps is as simple as possible, rendering the controls most easy.