NEW SCOTTISH LIGHTWEIGHT.

350 c.c. Barr and Stroud Sleeve Valve Engine Embodied in the Three-speed Royal Scot Motor Cycle.

IT is not surprising that one ot the earliest firms to fit the Barr and Stroud sleeve valve engine should be a Scottish concern. Actually the Royal Scot motor cycle, made by Donaldson and Kelso, Anniesland, Glasgow, is the second machine marketed with this much discussed power unit, which was first described in The Motor Cycle last July, and which was among the most interesting exhibits at the recent motor cycle show.

It will be recalled that a single rotating and reciprocating sleeve is actuated by a horizontal stub extension which is held in a self-aligning bronze bearing eccentrically set in a timing pinion. Suitable ports are cut in the sleeve and in a symmetrical cylinder head. Tests have proved that the engine is of very considerable efficiency for its capacity — 350 c.c.

On Conventional Lines.

The remainder of the Royal Scot follows familiar lines, although the spring forks (of the Montgomery type) are not yet common on 2¾ h.p. lightweights. A saddle tank of simple outline rests on a sloping up tube, and the lubricating system at present is by plain hand pump. Transmission is by chain throughout via a Burman lightweight three-speed gear box, and the brakes are internal expanding on both wheels. The price is £85 solo.

It is intended also to market a light-weight sidecar outfit at a proportionate price ; and, in fact, tests have already been made with a sidecar attached. The machine has been found well up to the work of ascending the well-known test hills around Glasgow with a heavy passenger in the sidecar.

The Motor Cycle December 22nd, 1921.