John Blackman photographs and profiles Royal Enfield’s primary 350cc-class motorcycles of WW2

When first evaluated by the War Office in 1935, Royal Enfield’s civilian Model C 350cc motorcycle did not fare well. However, after the Dunkirk evacuation, availability became of paramount importance and large orders were placed with all the major motorcycle manufacturers for what were basically lightly militarised versions of existing civilian models. In Royal Enfield’s case, the 1940 specification Model C was so be supplied and finished to War Office specification as the WD/C.

The 346cc side-valve machine remained in production for almost two years, from 1940 to 1942, and although the basic mechanics of the ‘bike remained the same, it was subject to numerous detail changes. For instance, the original aluminium brake plates were replaced by steel plates (aluminium being in very short supply), pannier racks and a pillion were fitted and a filter was added to the engine timing cover to improve big-end life.

In the region of 16,500 WD/Cs were produced and the type remained in service until the end of WW2, but the machine’s perceived lack of performance was a constant source of criticism, a problem addressed by the introduction of the WD/CO in 1942.

Aside from the fact that the WD/CO had an overhead-valve engine (capable of delivering 14bhp from its 346cc capacity, some 50% more than the WD/C’s 346cc side-valve), you might be forgiven for expecting that the two ‘bikes had much in common. That was not the case; very few components were interchangeable. However, that’s not to say that both were not thoroughly conventional for the time, rigid tubular frames and girder parallelogram front forks being very much the order of the day.

Production of the WD/CO was nearing 30,000 by the time the lines closed in 1945. Once again, there were numerous detail changes throughout the run, but there was one major mechanical change. A temporary shortage of the usual Albion four-speed gearbox in late 1942 led to the 3000 machines ordered under contract C13870 being fitted with Burman gearboxes instead. These particular machines were designated WD/CO/B.

Among the more noticeable modifications introduced during the WD/CO’s production run were the fitting of check springs to the front forks and the deleting of handlebar grips and various rubber components, including steering dampers, as the situation in the Far East led to the supply of raw material for such luxuries drying up. From late 1944, ‘bikes were generally supplied with a Vokes air filter mounted on the tank top. There were also three different styles of frame. The first two were very similar but the third, later, type featured a pressed-steel top tube.

The WD/CO served with the Army, Royal Navy, RAF and Civil Defence units, and its on-road performance – a top speed of 68mph (109km/h) as opposed to the WD/C’s 56mph (90km/h) – meant that it was suitable for a wider range of tasks… convoy escort etc. But the type did suffer from a lack of ground clearance and the fact that the bottom of the crankcase was largely unprotected. Therefore it didn’t see much forward-area use where cross-county ability was an important consideration.

Both the WD/C and WD/CO were disposed of pretty smartly at the end of the War, with many – if not most – factory or dealer ‘refurbs’ being assembled from a variety of mismatched parts both new and reconditioned.

Both of the machines illustrating this feature are owned by well-known motorcycle collector, Bill Tipping.