It is a bit sad that the carbs on old British motorcycles are not able to be jetted as close to the optimum as modern motorcycles. I would expect a new 750cc Royal Enfield would perform better than an old 750cc Commando, however that should not be the case. I think in the 1950s, the British must have driven themselves insane while getting their race bikes tuned. When the Australians raced on the IOM in those days, they were only accustomed to the speeds because in Australia, we used methanol. The British Nortons in the UK were as fast using pool petrol.