When i got the Bike there was no AirFilter and he said it had been sitting for months. So that scared me, and i had never actually torn one down before. And i wanted to see what all was done. But if i had to guess i would say carb issues as well, he installed a twist throttle and i bet that is the issue. I am putting my A&S motor on my other bike and am going to use those carbs on this bike to make two good running bikes.