Motorcycle a three-speed gearbox and belt transmission. It was so popular with its users that it was nicknamed the "Trusty Triumph." By 1920, Harley-Davidson was the largest manufacturer, with their motorcycles being sold by dealers in 67 countries. In the 1950s, streamlining began to play an increasing part in the development of racing motorcycles and the "dustbin fairing" held out the possibility of radical changes to motorcycle design. NSU and Moto Guzzi were in the vanguard of this development, both producing very radical designs well ahead of their time. NSU produced the most advanced design, but after the deaths of four
BSA unit twins new cycle parts, including the "oil-bearing frame". Apart from cosmetic items, the cycle parts were shared with the Triumph twins. (Triumph was a subsidiary of BSA). To produce a 750cc machine for AMA Class C racing, BSA lengthened the stroke of Lightening's crankshaft by 11mm to give a displacement of 751cc. 202 machines were produced to meet the minimum production requirements. All were exported to the US, most to the East Coast distributor in Baltimore. By 1972 BSA were in serious financial trouble and the Firebird Scrambler was discontinued in an attempt to reduce costs. With rival British motorcycle manufacturer,