Hi - the twin carb A65 needs a tufnol spacer between the carbs and the head because the twin carb bikes have no inlet manifold to absorb the engine heat. I went out on my Spitfire last week, for the first time on a very hot night, and the bike spluttered to a halt after about 5 miles. Thinking it was a carb blockage I undid the drain on the carbs and was scalded by the screaming hot petrol that came out, how it didn't set fire I will never know! The hot fuel was obviously vapourising. A pair of tufnel washers seems to have cured the problem.
John.