The motor I'm rebuilding is mostly parts from a blown s5 NA that I picked up. It apparently ran like crap before I took it apart, which I find amazing due to the fact that one housing had a giant gouge in it, caused by a piece of metal stuck in the face of one rotor. Mileage on the motor is unknown, but it was rust-free. I've got a replacement rotor and housing, and I figured I should replace everything that can possibly be replaced. I'm noticing though that most rebuild kits don't come with bearings, and that leads me to my question: do bearings in a rotary even go bad like in a piston engine, where they can get 'spun' or damaged? What constitutes damaged bearings? If you were me, would you replace them?

Also, whats the best way to clean nasty rotors and housings?

 

Ive heard normal industry standards is if its showing more than 20% copper than get new bearings pressed in. That goes for the stationary gear bearings also. It is possible to spin a bearing in a rotary. All the 12A motors i had showed copper while barely any on many 13B's i had. Also if you need new bearings pressed in i would only trust a rotary shop since they have the proper tools. Even if you have to take a drive over an hour like i did its still worth it to know it was done right. It also takes longer for new bearings to break in properly. I heard over 2k miles.

Well anyways post some pics of your bearings if you want more judgment.