yea i'm shure that the rotor is out of balance . I remember one time i had wanted to change two bars on the opposite sides of the rotor and after doing that it was way out , then i started to weigh the bars and they were all over the place some like 1/2 pound difference . there is a way to get the rotor close to balanced in the combine without having someone come out with a portable balancer but i don't remember how .maybe ask your dealer . and are you shure that all the bars are shimmed to the same height ?
What I do is put the rotor in neutral and spin it by hand, it should stop and then roll back and stop for a final time. Now you know the heavy side is at the bottom and the light side is at the top. If it only needs a little weight to get it right, Just take a bolt out of the elephant ear, and get a longer one (Grade Eight) and a heavy washer or two, or however many it takes. Then bolt it back up with you're weights or washers to the back side of the ear. (Do the same if you have the AFX). Be sure you put them on the back side, so it does not ware from the material going through. once you tighten every thing up spin it again. When it is balanced it should just stop, and not roll back. Hope this helps. Not as scientific as a portable balancer but a lot easier on the wallet, and just as good.