Jetting has to be way out to actually stall at throttle. If its not blowing tons of black smoke then its unlikley to be a jetting problem with the main or needle. Lean carb settings will make an engine run hotter, but shouldnt stall it - just very flat power, poor acceleration.
Potential issue - did you change the pilot jet? did you totally unscrew the air/fuel screw? If you make the pilot too rich it will stall it, and if you completely took out the screw and forgot to put back in the little o'seal ring it will stall as soon as its hot. Where you may change a main jet by +/- 4 sizes to counter a modification, a pilot would only be changed by one size if at all?
Another possibility - check spark plugs and leads. Hot plugs and leads start to break-up and can lead to engine stalling. I used to have a bike that played up all the time when hot, but OK cold and it turned out a ignition lead had a crack in it so the plug wouldnt fire- yet I thought it was a carb setting problem.