So I have a 2002 Yamaha YZ250F. I bought with a just rebuilt engine. So when I start the bike, which for this to happen requires the throttle screw be around 2 turns. If not it takes forever (of course). Once started the bike runs but has a hanging idle pretty high. The only way to get it down enough is with the throttle screw but then it idles well and cuts out. The best I've got the bike to run would be with the throttle screw at 2 and the pilot screw at around 2. The bike starts well, hanging idle and then when I put it in gear it idles down. But then when I give it some gas it hangs on the idle again. Do I need to do a rejet? If so I will come back with the setting I have currently. Also, I noticed that the pipe glows which is normal. Is it also normal for the coolant to be boiling out of the overflow tube? FYI, I will be riding at elevations from 0 to 3000 ft. Warm, humidity 50% (can get much lower), precipitation 10% Thanks for your time. Safe riding to all.