i turned my 04 yz 450 into a street legal supermoto. at steady throttle, 1/8 to 1/2, going down the road it breaks up quite a bit. as far as the engine and exhaust it's all stock, i just replaced the piston 3 weeks ago with a stock yamaha piston, i had to make room in the air box for the biggest battery i could fit since i didn't want to buy a $500 external stator. so flipped the foam element and put it in the air box carb hole. I made some holes in the air box sides to make up for the lack of volume in the air box. Ive tried pulling the hot start and the choke when it breaks up going down the road to see if one or the other cleans it up but niether does. Ive also moved the needle clip up and down and swapped pilots and main jets with no luck. Ive heard that un plugging the tps lead can help but once in a while you loose all power. The valves are perfect. when you roll on to WOT it pulls like a 450 should. anyone have any good info?