Hub motor clicking noise

[Dark000]

My ebike started to make fairly loud clicking noise while hub motor (250w) is active. If I pedal manually whith motor off there is no noise. The noise only starts when the hub motor is active and kicks in. Also if I don't use it for a day or two there is no noise for the first 5km or so ands then it comes back. I also noticed that the slow klicking noise is heard when the back whell (the whell where the hub motor is) is spinned backwards. So if I push the bike back the noise start if I push it forward there is no noise. If I turn the pedals back there is no noise. The noise is only when the whell is turning backwards. With the speed of whell turning the noise frequency also increases.

I ask what the problem could be before I take it to techician. Is there something I could do myself.

[Bikemad]

Hi andto the forum.

From your description, you probably have one of the small geared mini hubmotors:



These motors have an internal unidirectional clutch mechanism (freewheel device) which only allows torque from the motor to be transmitted in one direction.
This means that the wheel (and hub casing) will manually rotate in the forwards direction without actually turning the motor itself. 

As the noise only occurs when the motor is running (or being turned in the reverse direction) it will either be something catching between the fixed stator and the moving magnets/drum which revolve around it:



Or possibly a fault within one of the two bearings on the axle shaft in the centre of the magnet drum which can be seen in this drawing:



You can find out more about what is inside the mini motors in this thread.

Unfortunately, you will need to dismantle the motor to try and see what is causing the problem.
If there is no sign of anything physically rubbing against the magnets or stator assembly, it may well be a noisey bearing in the centre of the magnet drum that is causing the noise.

Alan