AJS Motor Cycles, Plumstead Road, London, S.E.18.
Model 36/20. 495 c.c. four-cyl. o.h.c. A.J.S.; dry-sump lubrication; magneto
ignition; all-chain drive; oil-bath primary chain case; 4-speed gear, with foot control: fuel, 3½ gals.; 26x3in. (front), [q]x3.25in. (rear) tyres.
Price with electric lighting (solo) £89 5s.
WITHOUT doubt, one of the highlights of the Show is the new four-cylinder A.J.S. It is the first British firm which has been designed with the idea of producing maximum output, and manufacturers have no hesitation in stating that a supercharger may be fitted if desired.
The layout of the engine, with its two pairs cylinders set at 50 degrees, is unusual, especially as the camshaft drive, by chain, is centrally placed between the cylinders. The chain takes the form of a Y, with a jockey pulley at the bottom of the upper run of the chain and automatic tensioning on the Weller system. It is, in fact, a duplicated form of the single-cylinder A.J.S. camshaft drive, although only one chain is used.
As a result of this arrangement it is possible for each cylinder to have its own overhead camshaft. The camshafts are connected to the upper sprockets by Oldham couplings, so that each unit may be removed without disturbing the timing, or any other unit.
Two carburetters are used, each feeding one vee, and two magnetos are bevel-driven from the crankshaft through a short vertical shaft. The magnetos are mounted in the form of an inverted V on the offside of the engine.
Hairpin valve springs return the valves and duralumin rockers, with tappets, transmit the motion from camshaft to valves. The two-throw crankshaft is of massive construction, and is carried in five bearings. Forked connecting rods are used, so that the cylinders are in line.
The machine in which this beautiful engine is carried is designed on standard A.J.S. lines, and since the full description published in our issue of November 28th the only outstanding change is in the exhaust system; the two pipes on each side now lead to a single silencer.
There is not much visible change in the single-cylinder overhead-camshaft A.J.S. models. The three-fifty is priced at £55 2s. and the five-hundred at £75 12s., in competition form, and at £70 7s. and £80 17s., respectively, in racing form. The racing models are fitted with 7 to 1 compression ratio pistons, but pistons giving a ratio of 11 to 1 are included.
Model 36/12. - 246 c.c. single-cyl. o.h.v. A J.S.; dry-sump lubrication; coil ignition; all-chain drive; oil-bath primary chain case; 4-speed gear, with hand control; fuel, 2¾ gals.; 26x3.25in. tyres. Price with electric lighting (solo), £39 18s.
As an example of a smart, light touring machine with a good turn of speed this model is admirable. In Model 36/22 the single-port engine gives place to a two-port, and a magneto and separate dynamo are fitted. The price is £45 3s.
Three-fifty models with similar specifications are available at £42 and £48 6s. In addition there are two 498 c.c. side-valve singles with vertical engines at £50 8s. and £ 52 10s., and two inclined-engine side-valves of 350 c.c. and 500 c.c. The big-twin is unaltered except that it has a forked connecting rod.
Model 36/18. 498 c.c.. single-cyl. o.h.v. A.J.S.; mechanical lubrication; magneto ignition; all-chain driver oil-bath primary chain case; 4-speed gear, with foot control; fuel, 2¾ gals.; 26x3.25tn. tyres. Price with electric lighting (solo), £57 15s.
The 36/18 is a fast touring model with a constant-loss lubrication system, high-level pipes and duralumin rockers. It has a single-port engine, but a two-port counterpart is available at £ 63.
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