1933 Camshaft 'Trophy' Models. Apart from the Big Twins and the little " two-fifty," the only other entirely new machines in the 1933 programme are the two eagerly awaited overhead camshaft models, which are to be known as 'Trophy' models in view of Mr. G. Rowley's line performance on one of them as a member of the team which brought back the International Trophy to England in 1932. The 'Trophy' models will be known as Models 33/7 and 33/10, and will have engines of 346 c.c. and 495 c.c. respectively. Prices will be £65 and £70 respectively. Both models will have a very similar specification, and each will be obtainable in racing or competition form. The racing form will have a straight-through exhaust, no kick-starter, two pairs of footrests, a mudguard pad and specially tuned engine with alternative pistons giving compression ratios of 7-5, 9, and 11 to 1. The competition form will have an upswept exhaust pipe with tubular silencer, a kick-starter, a special crankcase shield, and compression ratios of 7-5 to 1 and 6 to 1 in the case of the 347 c.c. and 495 c.c. models respectively.
The single-port engine is an improved version of the 1929 type, with camshaft driven by an automatically tensioned chain, but the magneto is now placed behind the cylinder, and the dry sump lubrication system incorporates in addition to the usual gauze filter a fabric filter in the tank of the same type as that used on the Big Twins. A duplex pump similar to that fitted to the magneto chain cases of the series 'T' machines forces oil to the main shaft bearings, the big end bearings and timing gear, and also to the rocker box and both valve guides. All the oil in the tank is constantly circulated. 14 mm. plugs are used. The whole engine (see page 114) has been thoroughly cleaned up.
The specification includes a pivot mounted 4-speed S.A. gearbox with foot change, a 3 gallon fuel tank, twin float-chamber Amal carburettor, detachable rear wheel, hinged mudguard, adjustable saddle, and 26 in. by 3-25 in. tyres. A speedometer and engine revolution counter to match, as well as 'Magdyno' electric lighting, with or without panel, can be fitted on both models 33/7 and 33/10 as extras.
See also:
Model 34-7 3.46 h.p. Camshaft "Trophy"
