[Dafni]

Oh, this sucks. Never saw a bearing like that on a motor. Reminds me of skateboard wheels, and I had a knuckle bearing like this recently.
The scotch tape trick is a good idea. I always covered my Wanderer/Feigao back bearings right off the bat, and keep them oiled. (less is more, there)

Loosing both, ESC and motor, at the same time hurts. I hope you'll have some better luck with your next setup.