I’m new to this forum and here because of a Bafang mid drive problem. I bought three bikes from a distributor in China a year ago. The bikes were identical other than frame size. Two bikes work fine, but the third was a problem from the get-go. It arrived with a broken brake cut-off cable. That was replaced, but the bike wouldn’t work at all. It was determined that the controller needed to be replaced. That was done, and power arrived, but when pedalling on an incline, the motor stutters. Has anybody ever encountered this, or can anyone give suggestions as to where the problem might be. The seller has disappeared.