Originally Posted by John Wallace2
I see al lot of possible causes to your problem have been posted let me add one more. When servicing a motor one thing that usually happens to me at least is that one of the spacers on the end bell side of the motor get caught behind the sensor board and end bell. If not noticed the spacer can get into the motor and make strange noises.
So I took the motor apart several times to check each of the ideas for things to check. In the end I think its just the way the front bearing sounds. Maybe its worn or just noisy. I will probably replace it when I can.
Things I checked:
Rear Bearing: Seated fully in endbell (How does it come out anyway?)
Sensor Board: Clear and clean. Tightness of screws seemed to have an effect on sound indicating a bind of some sort.
Rotor: Not contacting anything inside, that I can see.
FOD: No Foreign debris found
Shims: Tried with the stock one on back and two on front as well as just one on front. No difference in sound but the rotor was more free. Rotor moves about 1mm with 1 shim and about 1/2mm with 2. Ended up staying with 1 shim.
Front Bearing: Seemed to be the source of the noise. If I pushed sideways on the rotor while it was spinning and making the noise it would quiet a bit.
Noise: Not overly loud but not that nice whine sound like most motors have.
Thanks for everybody's suggestions.