production was halted during the first world war as the factory switched to the manufacture of aeroplane engine parts. in an article in 1916 they outlined that they planned for their post-war models to benefit from the aeroplane engine experience with lighter cylinders and alloy pistons. although engaged in war work they did some development on future models, and in 1916 showed a 3.5 hp "after the war" model (smaller than their normal machines with 85mm bore and 88mm stroke). this was fitted with a patented paraffin vaporiser to allow it to run on paraffin after starting on petrol (petrol being in short supply).