Knocking Q128C motor.

[Neil5403]

Went for a ride today and noticed a knocking noise from the rear end. Upon investigation it appears to be coming from within the Q128C motor casing.
The bike rides fine, everything working as it should but the knocking is getting louder.
Can these motors be worked on, parts replaced etc?
Anyone any idea what may be wrong with it?

 

[Nealh]

You will have to post a vid clip so we can hear.

 

[Neil5403]

You will have to post a vid clip so we can hear.

Ok. I will try and upload a video today.
If a new motor is needed, are they still only available from BSM battery in China or is there anyone more ‘local’ with quicker delivery?

 

[Nealh]

Topbikekit sell them though currently about 28 days D2D, they also sell spares, cover plate with hub body, clutch's/planetary gears.

 

[Benjahmin]

Check your electrical connections, both the phasr wires and the hall connections. Is the motor plug fully home/engaged? Is it showing any sign of heat damage?

 

[Nealh]

I not heard knocking from hubs but you can get leccy resonance or a loud clicking noise as the current supply is interrupted by shorting/bad contact between connections. Though not a motor problem usually at the controller end or as Ben has mentioned at the motor wire connector.

 

[Neil5403]

It sounds more machanical noise than electrical. I disconnected the brake disk but no change. Hopeful it was that.
I will upload a video when I can figure out how!

 

[Sturmey]

The freewheel can give a very deep knocking sound if bearings loose. It sounds as if someone is hitting the hub with a hammer every turn of wheel.

 

[Neil5403]

The freewheel can give a very deep knocking sound if bearings loose. It sounds as if someone is hitting the hub with a hammer every turn of wheel.

That sounds exactly like mine is..

Knocking hub

 

[Benjahmin]

OK, that's not electrical.

 

[Sturmey]

That sounds exactly like mine is..

Knocking hub

It hard to tell. It could be a wheel bearing either I suppose. With the bike turned off and wheel not moving, try grabbing the freewheel gear cluster with your hand and check for sideways movement. Also check wheel for roughness when spinning forward with your hand. One way to eliminate the freewheel from our inquiry is to tie up or take off the chain and try spinning wheel or even 'ghost pedaling' bike on flat road with chain off.

 

[Neil5403]

It hard to tell. It could be a wheel bearing either I suppose. With the bike turned off and wheel not moving, try grabbing the freewheel gear cluster with your hand and check for sideways movement. Also check wheel for roughness when spinning forward with your hand. One way to eliminate the freewheel from our inquiry is to tie up or take off the chain and try spinning wheel or even 'ghost pedaling' bike on flat road with chain off.

I took the cassette , chain and brake disc off and just spun the wheel and the noise/knocking is still there. Is the centre hub, removable/replaceable?
There was a slight movement in the gear cluster but I don’t know how much is normal!
I would order another motor and then get this fixed in due course but the delivery time for a new motor is not short...

 

[Sturmey]

.....I took the cassette , chain and brake disc off and just spun the wheel and the noise/knocking is still there......

Its a geared hub with inbuilt clutch so when you spin by hand, the motor itself does not spin (but there is usually some light movement in the 3 planetary gears and clutch). These gears (and wheel bearings) are relatively cheap but motor has to be dismantled. I have no actual experience with this particular motor.
Sometimes these noises either get better or get worst if you keep using but its nice to know what's causing the noise.

 

[Neil5403]

I may have a go at taking the hub apart tomorrow. It needs fixing or replacing so got to do something. Is there anywhere that I could send/take it to for repair?

 

[Nealh]

Ask Tony at Woosh bikes.

 

[Neil5403]

Anyone got a spare Q128C lying about they would like to sell, so I can get mine back on the road. I can then take my time getting mine fixed and use it on another bike?