Now that is a proper "Sports" Bantam! Sounds as if it has had an injection of testosterone or something similar! I am sure that once it is properly set up and run in then it will not overheat etc. Those might be "sustained high speeds" for a Bantam but there are loads of little two strokes capable of sustaining those speeds forever - just needs a bit more perfecting and refinement than BSA ever put in to their commuter bikes.
Is that the 64mm piston? Going well but I would be nervous of it getting warm and seizing at sustained high speeds like that. Also, was the air wide open? How much oil was in the petrol?
25:1 on the oil (high quality fully synth) It has an alloy cylinder with nikasil plating so heat is less of an issue than on the stock cast iron barrels . I am not nervous lol
