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Is my hubmotor repairable


10 µW
Feb 24, 2021
Hello everyone
I really need help from some of the skilled people on this fantastic website.
I apologise for i rarely use computers and have very basic knowledge regarding e bikes.. Im new to the whole e bike scene.
6 months ago, one of my brothers mates left to move overseas permanently one of the many items he left and donated to my brother was his enduro style e bike. My brother was not at all interested in it, so he gave it to me.
The first time i charged it up and went for a ride i was hooked. 6 months I've been riding this bike daily and i can't say how much i absolutely love it. And i just love riding it around exploring.
I live in Australia in the middle of no where and ive pretty much ditched my car and now i ride it everywhere.

It had only 4 of 5 hours of use since brand new when it was given to me now after ive been thrashing it around some rough dirt tracks for months i couldn't believe how worn out it was
So i thought i had better get someone who is qualified to assess the state of the bike for me. I found out the bike is a chinese clone of something.
Its72 volt 5000 watt It had some serious suspect parts on it to say the least. Eventually i found a mechanic in the local paper (after looking for months for someone to help me) who says he has experience working on e bikes, he said for a small fee he will come and check my bike for me.
To cut an already too long story short, basically he replaced the forks, handlebars, brakes some drive components and he was in the process of replacing the wheels. This "mechanic " said i must replace the phase wires for the original wires were melting. I bought the wiring and wheel bearings he said i need and gave him the bike.
Anyway he has done a disappearing act leaving me with my rear hub motor in pieces. The thing that im concerned about the most is somehow he has cut through or somethings hit a few of the fine copper wires on the stator and the wire that comes out of the motor and connects to one of the phase wires.
My question is can i get that damaged section repaired?
Does it even matter?
I was told it would be quick easy cheap repair it could just be soldered up?
Any advice would be so much appreciated. I have so many more questions regarding joining the wires back together, putting the wheel back together ect..
Thanks so much in advance
Screenshot_20230301_144650_Gallery.jpg20210718_061617.jpg20211013_121245.jpg20210718_061756.jpg20210204_152941.jpgScreenshot_20230301_144650_Gallery.jpgScreenshot_20230301_143929_Gallery.jpgMelted phase wires .jpg20230301_143647.jpg


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It's tough to tell which of those windings would match to which; if they're not correctly matched the coil isn't complete and / or it doesn't have the same properties. It's also difficult at best to connect across broken end-turns like that, as there's usually little clearance to the sidecover at that point.

You could try to repair that, but it's much simpler to replace the motor. If you can get the same motor you could just swap out the stator (since yours is already removed from the core) and not have to rebuild the wheel. It looks like several different "generic" motors I've seen, similar to those from MXUS, NPB / NBP, or QSMotors.

The melted phase wire was caused by a poor connection at the point it bolts to that terminal block. That's why the nut is darkened--the insufficient clamping force of the bolt/nut on the "ring" terminals of that phase wire connection made a much higher resistance than it should have, and that made that point heat up so much it caused the damage you see. The only part of the wire that has to be replaced would be any of it that is heat-damaged, and that's probably only right there near the terminal block for the controller side (the motor side is going to be replaced with the motor anyway, unless you can manage to repair the motor windings).

Another one has it's bolt&nut replaced by a philips screw and that seems to already be causing excessive heating there as well. The third one seems ok from what I can see in in a quick look.

I'd recommend replacing that terminal block, preferably with individual bolts (and washers, lockwashers and double-nuts) for each phase wire. You will probably need to replace the ring terminal on the controller side of that phase wire, and shorten that wire to eliminate the damaged portion. While doing this you should also shorten one of the other two phase wires, so that all of them will be "staggered" so that none of the connection points overlaps any other, and they can't short together. Then insulate the bolted-together connections individually.
Thankyou so very much for such a comprehensive detailed response i not 100% sure i fully understood all of it. But i doo now a friend who has a bit of knowledge in this area has spelled out exactly what your suggesting i should do in your reply
i will be implementing all your suggestions
I would like to replace that motor with a better quality one from a more established and trusted brand.
My problem is that currently i have limited finances to spend on ebikes. I am currently looking for a the most inexpensive solution possible. I would like to replace just the stator, but ive looked and have no idea where to purchase one from. I only get results as where to purchase an individual stator from is Alibaba and AliExpress, which would be fine, except for the months-long wait for shipping.
I've read various articles which state that the qs205 style hub motor is so common and it's been cloned by many no name or Chinese manufacturers. You u can commonly find them both new and second-hand for around or under 100 bucks,.
Would anyone know where I could pick up a stator? new or second-hand or complete hub motor ? thats is inexpensive just to get me through until I have the funds to purchase the proper parts .
Please any help as to where or what type of Place would sell expensive motor components would help so so much and oh so muchly appreciated!?
There's not really anywhere to buy a stator from that is any cheaper than a whole motor, unless you find an individual with one that is keeping the rest of the motor for whatever reason but getting rid of the stator (assuming it still works--I have gotten a couple this way, but it's rare--they usually replaced the stator because it's broken in some way).

The QS205 has a few different versions; the 50H is what I have here, and could be what you have a version of there. If your motor cover has any markings on it at all, they might help determine the source of the one you have, and make it a bit easier to find a replacement that will fit inside it. I see what is probably a serial number starting with ZC, but I haven't seen that abbreviation before for a motor company name, so don't know who it is.

50H means 50mm stator lamination width, IIRC, so you can measure the width of those to get an idea of what stator width you would need to replace just the stator. You also need to measure the shoulder width at the bearing shoulders (the fat part of the axle just outboard of the stator itself), so that it will fit the covers you have, and the axle shoulder width (the next axle-diameter transition, just outboard of where the cover sits) so that it will fit the bike frame.

You can buy a whole motor and just pull it's stator out to replace yours with, the tools used to take one apart are the same ones used to put it back together. (primarily a 3-jaw gear puller)

If you're replacing the whole motor, you still need the axle shoulder width measurement of the one you have, to fit your frame. If you can measure the spoke flange width and distance from the axle center to the spoke holes, and get a motor that matches those, you can also reuse the spokes you already have to lace the new motor in place of the old one, otherwise you may need new spokes as well (call it another $50+). If you have not laced a wheel before, it's not terribly hard, just tedious, and there are many resources to show how to do it with just a few tools (which might cost up to another $50+ depending on what you already have). I would recommend practicing on an old wheel you don't need first, to get an idea of what you're getting into and if you really want to finish it once you start, and learn the basics on.

If yours is a QS205 clone, it's probably the same measurements as the QSMotors QS205, and that info is on their website for the various versions.

Note that clones tend to be cheaper because they are less well-made, or less-capable, such as being wound with less copper, etc. But as long as the dimensions are the same as the clone you already have, one is likely to be as good as any other.
Just save up and buy a replacement motor/laced wheel. Easy to install, done! and back riding. Saves a lot of heartache trying to piece together bits and pieces of hard to obtain parts on the cheap.

Justify it by realizing all the money you have saved during this period you weren't using your car. And double justify it by remembering you got the bike free! ;)