1 brand new motor is noisier than the others

[miky94]

I tested my brand new motors and as you can see the second in the video is noisier than the others, is that normal?
I tried swapping it to anoter ESC with the same result
turning it by hand feels the same compared to the others, maybe a little bit more jerky, but it is probably just an impression
the screws are tightened the essential and less than on the other motors
I removed the bell but I didn't find anything that can cause this, the bearings feel smooth and the stator isn't moving around, I don't seem to see scratch marks on the magnets.
any suggestions?

 

[RENOV8R]

I suppose with the tight tolerances, there could be a defect that you can't see. If it performs properly and isn't overheating, I'd just fly and see if it goes away as the motor is broken in.

 

[miky94]

I'll try to see if it overheats, otherwise I'll try to fly.
my concern is that it will seize up crashing my quad.
maybe getting consumed where there is friction the noise will disappear?
I asked the seller even if it is been a while from when I bought it to when I tested it, I'll probably buy a spare one.
do you think the third sounds good compared to the first in the video?

 

[Dugdog47]

I've found after a few flights new motors start sounding quieter, better, cooler? They'll break in and be fine, send it!!!

 

[miky94]

I hope you are right, later I'll test if it overheats