Alright I got an 01 cr250 with a crappy stock mikuni 38 mm carb. Im buying a pre jetted keihin 38mm air striker carb. Im making this post to possibly help someone. If it fixes my issue or not ill be happy to give feedback. Because if this carb don't then the next step is power valve adjustments and timing adjustments. Because thst would be the only issue if it dont fix it then. Then I may have to lean the carb out with the jets. According to carb part warehouse customer service ill be fine if im not above 3000ft sea level. Im 500 ft. Being your own motocross mechanic sux. I just wish there was a jetting diagram for specific year and model along with weather temp, sea level, humidity and etc.