Brough Motorcycles

[2] The three models were the HS - which was fitted with a two-speed countershaft gear operated by dog clutches, with chain drive to the gearbox, and John Bull rubber belt drive to the rear wheel over an adjustable pulley allowing the top gear range to be varied.

[4] At the end of 1918, George Brough had been developing his own ideas on the design of his father's flat twin engine.

A new 500cc job .The engine had detachable heads with the valve seats integral and the rockers 'enclosed in neat aluminium cases'.

Robert Blay is also later recorded as the first owner of a Nottingham 1922 Mark I side-valve machine, registration AU 5708 Upon hearing the name of the new motorcycle company, his father was reputed to have made the comment, "I suppose that makes mine the Brough Inferior".

The two sizes of Brough flat-twin engine were still in production in 1922 when Brough announced a modified version with roller cam followers, light aluminium pistons, removable valve seats, and the engine base extended to mount the three-speed Sturmey-Archer gearbox.