I just got a TTR-90 for my two kids. I can not make the thing run without leaving the choke half on. I have adjusted the idle needle all the way out so it will idle down when the choke is half on? But I when I adjust it in and turn the choke off it will not idle. I can make it run but the it is hard for the kids to learn to ride when it does not idle. Please help? I bought it used but it is a 2004 with very little use. I always run the carb out of fuel between rides because it can sit for weeks at a time.