V1, V1.1, and V1.2 (And Why It Sucks)
Evidently, the first few iterations of this motor was not great. Here are the issues to be corrected for V2. However, the build documentation is still provided.
1. Bad Bearing Config
A small bearing was used near the center of the rotor, which caused some uneven spin/wobble. This was later corrected for a wider bearing, toleranced to join the stator and rotor in a concentric fashion.
2. Magnet Rub
However, even with the wobble reduced, the initial 0.75mm airgap was still too small to account for JB weld-buildup under the magnets in the motors. A slightly larger, 1.25mm airgap was implemented in V2.