I have a yamaha dt50rsm from 2008 and my idle wont go below 5000. I have tried to screw the idle screw but the idle is still stuck around 5000. Does anyone know what my problem might be and how to fix it?

You either have a massive leak in the inlet system, or more likely the slide or butterfly in the carb is stuck open

or cable sticking. if idle hangs, def too weak, if bogs too rich