Combines rotor bouncing

Rotors are not supposed to float in the support plate. Check for loose hardware or bad bearing. Rotor may also need to be balanced. Check for anything missing that may be throwing it off balance.

I had (I think it was the TR97 I had) a rotor bearing spinning in the bearing holder block. It wouldn't do it all the time but I would catch it doing it once in a while when I would give the combine the walk around with it running. That may be your problemIJ If that spun enough it would be loose and could catch fire. I would take apart and replace the bearing and holder. Not to hard to do but you have to take the feeder house off. Good rainy day job. Ilnh

I've seen someone replace a rotor bearing on a TR86 without taking the feeder house off. My two cents worth.

it can be done without taking the feeder off but for how easy it is to take the feeder of it is worth taking it off and also by taking it off it gives you a chance to check a few more things.