The 1950 Douglas Mark IV was a British flat-twin motorcycle known for its advanced and comfortable ride, achieved through innovative torsion-bar rear suspension and leading-link front forks. It featured a 348cc OHV flat-twin engine and was visually distinguished by teardrop-shaped rear toolboxes, a front mudguard mounted to the brake plate, and frame-mounted pillion footrests.
While not a speed demon, it was a stable and well-handling touring bike. The 348cc overhead valve (OHV) flat-twin engine was mounted across the frame, giving the bike a low center of gravity and inherent balance. While not a high-performance engine, it was notably smooth and reliable.
Suspension: The MK4 was celebrated for its advanced running gear, which contributed to excellent handling and a smooth ride.
Douglas was a British motorcycle manufacturer from 1907 to 1957 based in Kingswood, Bristol, owned by the Douglas family, and especially known for its horizontally opposed twin cylinder engined motorcycles and as manufacturers of speedway machines.
Several German manufacturers began making motorcycles with the Douglas layout when engine manufacturer BMW made its M2B15 flat-twin proprietary engine available in 1920.[20] The M2B15 had been developed from the reverse engineering of a Douglas motorcycle engine.
Multi-vendor Vintage Bikes and Parts. Buyers premium applies of 13% plus GST of 1.3% (a total of 14.3%) for bikes and 15% plus GST (a total of 16.5%) to all other lots. GST is part of the premium only and is not applied to second-hand goods.
Auction will be held online from 09:30am AEST on 9 August 2026 at our Seven Hills address. The auction will be called via the HiBid website (linked from our site) via audio with visuals of each lot. Inspection of lots is available by appointment prior to the auction.
