Some customers have reported a clicking noise from the rear hub of the Bafang cassette motors. This seems to appear only while you are pedaling, and cannot be heard when coasting. In some cases, this can also be heard when pedaling backward. It may sound like clicking or knocking noise heard every half revolution of the crank.
Remember the noise can come from any of the mechanical parts like shown here. If after reviewing this the noise is confirmed to be coming from the Hub you can proceed with the following:
We found out a quick adjustment of your rear wheel can sometimes resolve this issue quickly because while shipping the boxes can get roughed up causing some misadjustments. All you will need to do is to loosen up the 18mm nuts and reseat the tire all the way into the fork. Then tighten the components back to its original torque and retest. We found out this has resolved 90% of the reported issues. Also, greasing the Hub and gears has fixed it in hot dry areas.
If the noise is still appearing then you might have an issue with your Hub. This has been reported to Bafang, and the noise can be addressed by swapping the cassette tower. The noise is difficult to detect unless the bike is ridden in quiet environments. This does not reduce performance, and the only symptom is the annoying noise. We will continue to investigate the root cause of this issue that is affecting a small number of bikes. If you experience this noise, please contact Customer Support and we will resolve the issue under warranty.