Thanks all for the advice. I have done everything that anyone has sugested. None of it worked.
My new carb arrived. It is not a perfect match but close enough. I used the original top plate,slide, needle, jets, and the bowl from my old carb. I plugged an extra hole on the engine side of the carb. I did not mess with the float. I kicked it once and it fired right up. It runs smooth and has huge bottom end power and top end too. I am not able to ride this extensively at home so I do not know how it will perform in a real trials but I hope this weekends 2 day trials at Roswell New Mexico USA will turn out OK.
Many thanks to all of you who took the time to think about and offer advice.
Special tahnks to Bob Rowland, Adrian Lewis of Lewis Sport, and Tim Pilg of American BETA. These great people went way beyond anything I could ever have expected in there efforts to help me out of this maddening problem.
I guess I will never know what the problem really was.
Thanks All