Further to my earlier posting I can now add more corrections and info about this machine. The carb was a Type27 twin-float Track Amal, repeat Amal overbored to one and five sixteenths and converted to take a second jet that comes in just under half throttle, Binks style. Main jet 1000, second jet 700. Special float needles to close quarter inch diameter holes in caps. Both floats will pass two pints of fuel in less than 10 seconds……The fuel mix used by Derrick was one gallon of Methanol (methyl alcohol),a quarter of a pint of Castrol M40 oil, and “half an egg cup” of Amyl Acetate. Main engine lube was by drippers and Castrol R40. Capacity was 647cc. Fuel consumption approx 4.5 mpg. Derrick bought it from Arthur Breese in 1962. When Derrick last raced it, in 1990, it was it’s first outing for 25 years, and this was at Bovingdon, Herts.. I bought it 15/09/99.