Motorcycle was producing over 500 bikes. Other British firms were Royal Enfield, Norton and Birmingham Small Arms Company who began motorbike production in 1899, 1902 and 1910, respectively. Indian began production in 1901 and Harley-Davidson was established two years later. By the outbreak of World War I, the largest motorcycle manufacturer in the world was Indian, producing over 20,000 bikes per year. During the First World War, motorbike production was greatly ramped up for the war effort to supply effective communications with front line troops. Messengers on horses were replaced with despatch riders on motorcycles carrying messages, performing reconnaissance and acting
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,