My dad found me a 450g ls and from the beginning it has had some issues with the motorcycle idling unusually high. We ended up cleaning and rebuilding the carbs more than once, sending it out to a professional. We thought that fixed it but on our ride today we found that the problem is still there. When the bike is started it jumps up to 3000rpm and stays there. Sometimes when we rev it, it will fall, but very slowly. It seems to drive fine when the bike is moving, but as soon as i try to make a stop it will jump up again. We tried playing with the choke but that rarely brings it below 3000rpm at a stop.

what are some things that could be causing this? I have had the bike for 2 or 3 years now, but have been unable to get enough ride time in to get my license.