Production of the Model 50 began in 1932 using a 350cc version of the engine fitted to the Model 18 and the ES2. The frame and running gear was very similar to the Model 18.
In 1934 a second drive-side main bearing was added and the timing gears were revised, reversing the direction of magneto rotation in the process. A Burman gearbox was fitted in 1936, and a new cylinder head appeared in 1938 with different studs and coil valve springs replacing the hairpins.
Also in 1938 a new silencer made its appearance to less than universal acclaim, gaining the moniker of "cow's udder". "I do not consider the design very aesthetically pleasing", writes one gentleman. Others use words like fugly.
The postwar version had chassis and bodywork from the ES2 and 19S, and although the capacity remained the same as the earlier version, it had a different bore and stroke (71x88mm) and a higher compression ration.
From the 1959 Catalogue...
Now housed in the famous "Featherbed" frame and having road-holding characteristics identical to the racing machines, this 350 c.c. single cylinder model retains all the docility and desirable attributes of its predecessors. The incorporation of A.C. generator and coil ignition still further enhances this lively and economical machine. Note the fully-enclosed rear chain case available as an extra on all models.
From the 1960 Catalogue...
Identical in specification to the model ES.2 except for a smaller engine capacity, this machine is equally famous for its reliability and capacity for hard work. Modified gear ratios and a bonded clutch are improvements in this year's model. The lively single cylinder engine, "Featherbed" frame and world famous "Roadholder" front forks are features which contribute to the success of this splendid machine. Straight handlebars can be specified if preferred and a fully enclosed rear chain case is available as an extra.
Colours: Forest Green or Black and Silver,
COLOUR COMFORT RELIABILITY
World renowned for continuous hard service
From the 1961 Catalogue...
Identical in specification to the Model E.S.2 except for the smaller engine capacity, the Model 50 is also famous for its reliability and capacity for hard work. The new waisted "Featherbed" frame with narrowed petrol tank and slimmer dual seat introduced this year gives added style and, combined with the superb "Roadholder" front forks, lively engine and bonded clutch, makes this a most comfortable and responsive machine to ride under any conditions.
This is a big machine with a big performance combined with excellent fuel economy. Straight handlebars can be specified.
Smart two-tone finish in Black and Dove Grey.
Notes. 1. The Model 55 had dual exhaust ports, but only one exhaust valve so for an extra 2 pounds the new owner gained a slightly heavier machine, more chrome to clean, and otherwise SFA.