Hello I am new to the forum, and I am needing a little help with a bike that I have been working on. My father in law has a 2003 Roadstar. He bought a stage 1 kit from Yamaha, a Speedstar kit containing air box with k&n filter, ignition module, and jet kit. Also he bought some aftermarket cobra pipes, and an intake. The intake pretty much looked like the stock one. I pulled the carb apart and it had a 35 pilot and a 165 main jet. I replaced these with a 50 pilot and 170 main also put a needle in with the c clip in the third groove. I started out with the pms screw backed out 3.5 turns. I put this all back together and its back firing through the carb. It seems Idle fine and the upper rpm range is also great, but if you crack the throttle open about .25 it will start back firing. I have adjusted the screw as much as all the way in and 6-7 turns out with no help. I then took the carb back off and replaced the pilot with a 60, and it seemed to help somewhat, but just not enough I can adjust the screw out until it black smokes and I still get a back fire @ .25 throtle. I have checked for air leaks a number of times, so I am at a loss any help would be greatly appreciated..