I fixed mine by running the stock pilot and main with the 2002 needle in the middle clip with 1.5 on air screw, I found that the bike was sensitive to the air screw setting, but the needle was the cure, with that needle I was good from sea level to 3,000 feet 50 to 90 degrees, and only requiring air screw adjustments(and once a clip position change). All on pump gas.
By running the Keihin PWK carb, the bike had a bit "sharper power delivery" everywhere, I just found it became too responsive for woods racing, and the Mikuni was actually giving me a bit less abrupt power which I prefer for woods riding. Good luck!