Smoking and slipping... what the heck!?!

try a repack and see what happens. What mix are you running and with what oil? Also when you pulled your jets out did you check the pilot jet also? What size was it? If you main was jetted a little high the pilot may be high also. If the pilot is to rich it can cause a spooge problem also but some bikes do it no matter what. A lot of times its just the oil you are mixing and it doesnt burn real clean.