I know you have tried it before but! if useing the choke(continuasly)it makes it run better in top, not bottom, as it would be rich. would have thougt it was fuel/air.
If no matter what you do to the carb, wont make it rev out, would put down to electrics,can you borrow a running bike to swap parts one at a time? even the spark plug, I have bought brand new plugs, that are shite.
Before you start diconnect the green earth/stop switch wire to the coil(usally the nearst green wire) and if you can, the black and blue wire to the lights(T5 has a connector in the black box on the casing’s)it will basicly eliminate everything apart from the igntion system,then! work your way back plug,cap,lead,coil,stator one at a time.
Or you could just burn it! but save the fourth gear/carb and fly wheel as they will go on the p2!!!