you don't need to change the pilot jet. unless you did some major mods to the intake and recently upgraded your pipe.
have you done any mods recently?
your carb is mostly likely to be your prob, the needle has zero bearing on the idle circuit. the needle only comes into play at about 1/4 to 3/4 throttle. when you say your idle screw is in all the way, you mean that your idle is turned up to max speed right? where's your air screw set to? try turning the air screw all the way in to a light seat, counting how many turns it takes. then back it out to about 1 1/2 or 2 turns out.
it's a good idea to put a new plug in too.