I am having a problem where my bike will turn on and run just fine for about 5 minutes. you can put it in gear and everything and it will work just fine. But after about 5 minutes it will start to sputter, the idle will go down, and when you put it in gear it has no power and the only way to stop it from staling is to have it at full throtal and even then you only go about 10 mph. Any one have this problem befor or have any idea how to fix it?