I have a 2001 xr650r running a 68s piolet jet and a 155 main jet. Bike runs good though sometimes when I am climbing a hill it just falls on its face. It acts like it runs out of gas. When I get the pig turned around and headed back down the hill it starts up and runs good until I get it turned around and try it again. I took off the tank and made sure it was clean. Opened up the fuel line and gas flowed good through the line. I pulled the carb and made sure everything was clean and that the float and needle were working right and could find no problems. I am baffled. Please help.