NOVEMBER 3rd, 1921.
The New Imperial Programme.
A Loop Frame Lightweight with Engine and Gear Unit Assembly
As makers of lightweight motor cycles, New Imperial Cycles, Ltd., have had a wonderfully successful year. Perhaps the most outstanding success was the winning of The Motor Cycle Cup for the 250 c.c. Tourist Trophy, and in this respect it must be remembered that the firm have marketed their little T.T. model, and have also run it most successfully in reliability trials.
We ourselves have had some little road experience with the machine, and have found it thoroughly roadworthy and far from being a purely racing mount.
The A.C.U. Six Days Trials and the 500 Mile Race at Brooklands have added to the New Imperial laurels, and no fewer than thirty-five special trophies have been won, while gold medal awards are innumerable.
Similar machines to the Tourist Trophy type will be listed for 1922, but much interest will be concentrated on a modified type, which is the subject of the subjoined notes.
Novel Engine Mounting.
Driven by a New Imperial-JAP engine of 293 c.c., the engine is mounted on long bearer plates, on which are carried the magneto - directly behind the cylinder - and the three-speed gear box. Thus, the engine forms a unit with the main part of the transmission, and the whole can be detached from the loop frame by merely uncoupling the petrol and oil pipes and removing three accessible bolts. Many detail refinements are included in this unit. For instance, a breather is fitted to the gearbox, and this has been found to obviate oil leaks almost entirely. A rubber return stop has been fitted to the kick-starter, and ball and roller bearings will be fitted to the engine.
The loop frame is a sturdy piece of construction, and is particularly rigid laterally, as we can testify from a short run. Transmission is by chain throughout, and an adjustable shock absorber is fitted on the engine-shaft. The primary chain is well protected by a metal guard, and a special guard protects both top and lower runs of the low speed chain without entirely enclosing it.
Very wide domed mudguards are fitted, and the spring forks have undergone slight modifications. External expanding brakes are fitted to both wheels, that in the rear having aluminium shoes faced with Don friction fabric, the surface being ground true in position.
Rear chain adjustment is effected by screws carried in the fork end, and butting against solid steel blocks in which the spindle is carried. The comfort of the rider has been carefully studied, and, in addition to a comfortable saddle, large aluminium footplates are fitted, and ingeniously arranged leg shields may be added. These shields are unusual in appearance, since they lie rather on the inside of the leg than to the front; but, in this position, they catch the mud which is not trapped by the front guard, and act as air deflectors to increase cylinder cooling: they do not interfere with the simple device for adjusting the footboards.
The valve gear of the engine is particularly silent, and a large aluminium muffler with long tail pipe effectively reduces the exhaust noise.
Altogether, this is one of the most completely fitted and practical lightweights which we have examined, and on the road it is fast, silent, and easy to control.
The standard machine is fitted with 26 in. wheels. The tyre section is not yet finally settled; but a model will be made with 24in. wheels to suit ladies or short riders. Sports models fitted with 250 or 350 c.c. J.A.P. engines may be obtained, and these will have clutch but no kickstarter, and will be fitted with footrests, narrower guards, and lighter equipment. These models will be in addition to the chain and belt range.
It must not be forgotten that 8 h.p. passenger machines are a feature of the company's programme, though for 1922 only minor modifications, such as Timken roller bearing hubs and an ingenious sidecar standard have been incorporated.
Nevertheless, an 8 h.p. sporting mount fitted with the latest type of side-by-side valve J.A.P. engine will supply the needs of the "big twin" speed enthusiast.