Another Two-Wheeled Seven

From time to time the irrepressible engine of the Austin Seven appears in some new application, tackling a new task effectively and well. It entered the motor cycle sphere some time ago when George Brough, the Nottingham manufacturer, made a super Brough Superior with an Austin Seven engine and gear-box having a shaft drive to a twin rear wheel, the engine being accommodated lengthwise in the frame. We are now able to give details of another clever adaptation of the Seven engine to this form of transport, carried out by Mr. W. Jackson, of 26 Orchard Close, Bexleyheath, Kent.

To house a four-cylinder car engine in a motor cycle frame is no small problem, but when, as in this case, the engine is mounted transversely with no impression of bulkiness, the ingenuity of the designer will be appreciated. The finished machine has an appearance that would do credit to any manufacturer, a further tribute to the skill of the designer, who had a 41/2 inch treadle lathe as his only machine tool.

The engine is the standard side-valve unit of 747.5 c.c. capacity, watercooled through a modified Scott radiator. At first a motor cycle carburetter was fitted, but experiments proved, as might be expected, that the original Austin carburetter gave the best results. Coil ignition is used, with the battery charged by an ordinary motor cycle dynamo. The frame is built on the most modern principles, with suspension for the rear wheel by coil springs, again to the original design of Mr. Jackson. Transmission is by chain and three-speed gearbox, the primary chain running in a polished aluminium oil bath.

On the road the machine handles remarkably well. Although the maximum speed has not yet been attained, it is estimated to be in the region of 70 m.p.h., and petrol is consumed at the rate of 70 m.p.g. Oil consumption is negligible! The power unit is vibrationless, while the exhaust note, unlike that of most motor cycles, consists of a practically inaudible purr. In fact, the sound of the gears from a gearbox of rather ancient vintage completely overcomes all noise from the engine, either mechanical or exhaust.

The equipment of the machine is well up to modem standards, polished aluminium and chromium being used extensively in the finish. It has a low-lift central stand made for easy handling. With the exception of a few rough sketches, no drawings were made at any period during the construction of the "Silver Streak", as the machine is named.

L. S.

(Unknown full name)