[Serum]

A smoking motor is not good at all! (isolation from the copper is melting)

You are sure it's the motor? you can test the motor first by shortening two of the three wires in random order and see if there is some kind of resistance when turning the shaft (mechanical resistance i mean). Shorten all three of them to see of the resistance has become bigger and more consistent.

You dismantle the motor by getting the purple mounting plate stuck and turning the motor-body. I heard it's quite difficult to do. The aluminum body is so thin, that you can't put use pressure from two sides. You need to clamp it all around.