Q128 motor strip down

djah

Pedelecer
Apr 24, 2018
74
3
54
Ireland
Hi.
I’m looking for help in relation to the above please.
I’m getting info 3 fault code, motor hall signal abnormality. Does this involve stripping down the motor? If so, does anyone have a guide?
Many thanks
Dave


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JuicyBike

Trade Member
Jan 26, 2009
1,671
527
Derbyshire
Much more likely that one of the connectors along the cable to the motor is loose, or the external cable is damaged. Could simply be the plug to the motor is loose.
I wouldn't start stripping down the motor until you've first checked cables for damage and that connectors are tight at the controller end.
 

djah

Pedelecer
Apr 24, 2018
74
3
54
Ireland
All is good with controller and cables. I tried my other wheel and that works fine. I’m getting a very faint click in the wheel hub when the accelerator is operated but no movement.


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Nealh

Esteemed Pedelecer
Aug 7, 2014
20,105
8,216
60
West Sx RH
Before going down motor opening route confirm diagnosis with a multimeter check.
Better to know which hall is the issue.
http://www.ebikes.ca/documents/HallSensorTestingFinal.pdf

Hall repair guide.
http://www.ebikes.ca/documents/HubMotorHallSensorReplacement.pdf

To open the Q you need to make up a flat lever bar with an arc in it to go around the cassette hub and drill two holes to line up with the hub fixing holes, remove two of the tapped screws to the hub and screw the flat bar in to these. Once done apply force ACW to open. My one was quite tight to open but did go with good leverage, when doing up again don't do so, so tightly.
 
Last edited:

djah

Pedelecer
Apr 24, 2018
74
3
54
Ireland
As always, nealh, thanks.
My motor has julet connectors so I guess I will just have to open the hub.
I’m hoping that Bmsbattery will step up to the plate and send me a replacement. It’s only 2 months old with 165 kms on it.


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jarob10

Esteemed Pedelecer
Jan 22, 2017
270
83
51
Uk
I had to use the vice method to open up my q128c. No way was that cover shifting using a home made tool (m5 cap head screws not man enough)

I too have had hall failures, along with pawl failures & a side cover shearing. These all occurred within 100 miles of new, across a couple of motors.

I’ve kept the failed motors for spares - once past the 500 mile point I’ve found these motors to be faultless.
 

djah

Pedelecer
Apr 24, 2018
74
3
54
Ireland
Thanks for your reply.
What’s the procedure with the vice method?
I have tried the homemade tool but it’s not budging.


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jarob10

Esteemed Pedelecer
Jan 22, 2017
270
83
51
Uk
5DE4D33C-9E19-407F-984F-41B34920D26E.jpeg 0B2D93C6-3D06-4688-88D6-31612DEC0F41.jpeg Place the motor spline side down, then clamp the vice into the thin exposed edge of the side cover. It’s a case of incrementally tightening the vice whilst rotating the wheel until the cover turns. Scratching the aluminium cover is inevitable, but the scratches will be hidden by the derailleur cluster

Sadly bmsbattery have told me they can’t supply spares for the motor - ideally you’d just replace the hall sensor board. Your only option is therefore to replace individual hall sensors on the board - if you have any luck with this let me know!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,105
8,216
60
West Sx RH
Leaving the hub built in the wheel offers more leverage with a homemade leverage tool, some times it just requires a slightly long handle to exert the required opening force or a sharp tap using a heavy club hammer.
Once it moves if only 1/8th turn, undoing is easy then.
 

djah

Pedelecer
Apr 24, 2018
74
3
54
Ireland
Thanks guys. Will keep trying. Another motor on the way from Bms. It’s going to be a pain lacing the spokes in but there’s a first time for everything.
I’ll get the motor open somehow. The parts could be handy.


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jarob10

Esteemed Pedelecer
Jan 22, 2017
270
83
51
Uk
Thanks guys. Will keep trying. Another motor on the way from Bms. It’s going to be a pain lacing the spokes in but there’s a first time for everything.
I’ll get the motor open somehow. The parts could be handy.


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IMHO you’re correct to persevere with this motor, it’s superb

You don’t need to lace spokes onto the new motor - instead you can renew the motor core of your existing wheel. This all depends on getting that pesky side cover off. Get angry with it :)

Whilst you’re in there, upgrade the freewheel pawls to dtswiss versions (I’ve had the original pawls self destruct), and apply motor oil & thick grease to freewheel splines & pawl pivots respectively