The brothers William and Edward Douglas founded the Douglas Engineering Company in Bristol in 1882. Initially doing blacksmith work, they progressed to foundry work, and then acquired the flat twin design of WJ Barter, the founder of Light Motors Ltd. Barter had produced his first single-cylinder motorcycle between 1902 and 1904, and then a 200ccm horizontal twin called the Fair but the Light Motors Ltd. failed in 1907 and was taken over by the Douglas family. From 1907 they sold a Douglas 350 Twin version. In 1915 the engine was placed lengthways in the frame with belt final drive, and electric lighting.



In the 1920s Douglas built the first disc brakes, and had a Royal Warrant for the supply of motorcycles to the Princes, Albert and Henry. Douglas motorcycles also became popular in dirt track racing and initially the 1923 RA model with disc brakes was favoured. This prompted Douglas to build specific dirt track models. These bikes gradually increased in size and power with 500 cc and 600 cc engines fitted to the DT5 and DT6 Dirt Track models in the late 1920s and early 1930s. The engines had hemispherical heads and a short rigid forged crankshaft. They dominated dirt track racing for about three years. More specs and user manual of Douglas Twin you can see in next overview.