High Idle After Warm Up

[Banana1]

Hi all, I have posted about this problem before, sometime last season, but I've made some changes to my bike and this problem still persists. As it is right now, my XJ starts fine, cold or hot, but after the engine has warmed up the idle sits at 3k+. Right now my temporary solution is to just twist the throttle backwards hard enough to close the butterflies almost all the way, but this is really getting on my nerves. I have a stock airbox and muffler, cleaned and balanced carbs, new carb boots, and one size larger than stock idle jet. This problem has been there since I got the bike, when it was straightpiped, pod filters, and stock jetting, but it's persisted through every part change. Does anyone know what could be going on here?