Just a couple of points on carbs.
the mixture adjusting screw only adjusts the idle mixture. with the engine running screw the mixture screw in slowly until the engine starts to hunt and slow down, then gradually screw it out until the engine runs smoothly.
when you push the throttle it moves on to the primary stage, where the main jet takes over on a single choke carb (aircooled), if you have a bis it has a weber twin choke which is two carbs in one the primary and secondary chokes, if the engine has been modified the best way to get it set up is to go to a carb specialist who has a rolling road and they will be able to sort out the correct main jet, air correction jet, and the emulsion tubes if they are removable, you do need the right equipment to do the job properly to gain power and economy.
