Bodi,
I know, I haven't heard of one failing either. However my bike was a real POS when I got it.
So in the end I just found a replacement stator motor. My old one spun with a grinding noise. I thought that was normal until I spun the replacement one. It was smooth and quite. Now it doesn't short my battery either.
Looking at it, to replace the metal bush would require drilling it out and a lathe to make a new one. Given that starter motors are easily found on the net, I wouldn't bother. Replacing the whole motor was the answer.
Problem solved.
Rick.