Check the throttle slide they are soft metal on the Bing carb and wear quickly and can then jam, especially on full/ high throttle openings....I know from experience ?
just googles it, trials and scrambles,interesting box section spine frame, acting as fuel tank on the trials model, remembered seeing one in the late 60's
I am guessing, but 1. they have found a way around the rule on weight distribution? and 2, to lower the gearing? I think there is a rule about what tyres they can use, basically a standard road tyre
never seen a bike used in competition with the oil pump in use, they tend to be a bit generous with the oil and cause poor running. I run my 175 whitehawk on 60:1 synthetic 2t mix