not getting enough gas

[new250r ider]

My 86 has a shaved head and cylendar bringing the squish down to about .060, which seems to have improved power but I need to get more gas into the bowl. It will run fine forever at low to mid rpm but when I rev it out I get about 1/2 mile before it starts to sputter. If I idle for a few minutes I can do this again and the plug looks good so how do I go about getting more gas in, and how will I know if I go too far and am getting too much?

[cdrookie]

your petcock needs cleaned or the float needs adjusted

[86 Quad R]

agree'd! take the time and inspect the entire fuel delivery, from the tank down. and verify the float level and adjust if needed.