Is the engine bone stock, or has it been modified in any way? Have you tried adjusting the idle screw?
Need quite a bit more info, but the
motor should have an idle screw that is normally capped with a flush brass plug and then the fuel adjust screw. Some have said that their capped off idle screw was completely leaned out all the way out from the factory! Rotating it out 1-2 full turns should help a lot.
Always make sure engine is warmed up when adjusting for idle, and make small changes at a time giving the motor 10-15 seconds to adjust between changes.
Once you get it to idle properly, it is a good idea to do a plug chop and see if the fuel adjust screw needs to be messed with as well. Main jet shouldn't need to be messed with unless you have done intake and exhaust mods, so the good news is you should be able to get her running great with only some time and a screw driver
.