I think Its ok now. I adjusted the float which seems to have eliminated the hesitation.

Also I am intrigued by the tube which joins the bottom of the float bowl to the venturi. I can see how this would work: The vacuum from the venturi draws on this circuit but what is its purpose? I am guessing that this acts to help draw fuel into the bowl at high revs like a pump.

Also there are two open orifices which look like they will draw in water and dust and stuff is it safe to join these into the air filter with tubes or will the vacuum inside disturb the whole carby?