I've been trying to bring my grandson's 2018 RadMini back to life. The last problem is a lurching and grinding noise in the rear wheel. What I discovered is that the bearing on the freewheel side of the motor pretty much disintegrated. The bearing cage is in pieces and several of the bearings are missing in action. At first glance, it doesn't look like this part can be replaced without cutting the motor wiring. That seems a little drastic. Has anyone experienced this and replaced that bearing?
I recommend you to take a look at the Endless Sphere forum - lots of Bafang etc. related stuff:
https://endless-sphere.com/forums/
e. Perhaps this could be the way to disassemble the motor on your case too?
https://youtu.be/e2oS5HORtFk