Motor cutting out once per crank revolution

davewormald

New Member
We recently bought an ebike (actually an adaptive etrike from sport-on) with a Bafang BBS02B 500W motor. The motor starts fine when you start to pedal, but cuts out briefly at the same point in each crank revolution. In other words, in each 360 degree revolution, the motor cuts out for about 20 degrees. Here's a link to a video that shows the problem. It isn't wonderful, but you can hear the motor dropping out and coming back on just after the crank passes the vertical mark. This isn't terrible once you're up to speed, but if you're starting on a steep incline it can make things difficult. I also can't believe it's good for the motor to be cycling on and off so frequently. Has anyone seen this before or does anyone have any idea what might be causing the problem. I'm new to these types of motors, but I suspect there's a problem with the cadence sensor that I understand controls the motor. Any help would be appreciated.

Dave.