Barton engineering, comprised of Barry Hart, and Tony Ryan initially started out producing racing gear boxes for Japanese motorcycles, upon their early success they expanded to clutches, cylinder barrels and heads. Barton Engineering got the attention of Suzuki factory riders who were looking to get a leg up. They asked Barton engineering to come up with a better 350cc engine, which later evolved into a 500 Sparton motorcycle, once the motor was mated with the Spondon rolling chassis. The combination of Spondon and Barton produced the superbikes of Sparton. These motorcycles used 458cc engines based off of the Suzuki 380cc crankcases yet made close to 100 bhp, vs the Suzuki GT380 which was rated at 37 bhp. This was done through high end materials like magnesium cylinder blocks, and chromed aluminum bores, in addition to a water jacket. The 1975 Sparton bikes quickly set a new benchmark for speed at the 1975 Isle of Mann TT with a trap speed of 146 mph. Then in 1976 they won a 1-2 victory at the North West 200. This led to an even more experimental Sparton motorcycle model called the Phoenix, which was made in 500cc and 750cc 4 cylinders. These lightweight motorcycles were sold to independent teams which could provide feedback to Sparton so they could keep improving the motorcycle performance. Sparton also got involved with CCM and Armstrong later on. Alas, Sparton did not have the means to continue to compete at the high level of the Japanese manufactures, and their last year of production was 1982.