Broke my motor lead - new motor (and wheel build) or is it replaceable ?

[103Alex1]

Severed clean off :



Don't ask. Exhausted with all the to-ing and fro-ing over parts and bits for the basic build, with masses of work on at the moment following a very quiet January and early Feb, and took a short cut tonight trying to test the brake cutoff. Should have had the bike inverted or on a stand. Well I won't do that again.

It's starting to feel like this build is never gonna get on the road. I get one thing working and another thing breaks.. It would be a lot easier with a kit with everything you need supplied to plonk on a bike. Learned a lot but spent a fortune trying to get something nice. Inexperience has made every step of the way pretty hard.

What are my options ? I'd like a bike on the road inside 3 weeks ideally so can flog this lot on (and the drawer full of parts for extras) for what I can get for it, take a loan and buy an easy-fit kit bike or try to get the motor fixed / buy a new one. It'd need to be a 500W CST. I can realize £600+ for the bike as a MTB which leaves me about £800 down on the rest of the spend.

Can anyone help me out with outlining the options please ? Some serious decisions need to be made.

 

[mountainsport]

Hi 103Alex1,

I'm very sorry to hear about your damaged cable.Tell you what, if this project has taken you some valid amount of thought and time plus also being proud of yourself,dont let it go that easily.

And by the looks of that picture you could save yourself £££££ because if you are confident in removing the hub motors outer plate,then the inner bits,and not forgetting those dangerous magnets when replacing it all back together again (watching those fingers),you shouldn't have a problem.Then it is just a matter of replacing the damaged cable. I know that you can do it buddy.

Mountainsport.

 

[103Alex1]

Hi 103Alex1,

I'm very sorry to hear about your damaged cable.Tell you what, if this project has taken you some valid amount of thought and time plus also being proud of yourself,dont let it go that easily.

And by the looks of that picture you could save yourself £££££ because if you are confident in removing the hub motors outer plate,then the inner bits,and not forgetting those dangerous magnets when replacing it all back together again (watching those fingers),you shouldn't have a problem.Then it is just a matter of replacing the damaged cable. I know that you can do it buddy.

Mountainsport.

Thanks - it's my own stupid fault. Cutting corners to try to speed things up and winding up with a whole load more work to do and serious delays likely. These things always seem to happen when I'm hurrying coz I'm over my head. An "it'll take as long as it takes" attitude is a must sometimes - have never been any good with that - unless I've got excess time on my hands lol.

Not certain about the cable - there is this on BMS website but there's no mention of the Hall sensor wires which are sheathed in the same cable which appears to exit the centre of the axle on the CST motor :

A pair of 9Pin Waterproof Male/Female Connector Cable for Motor - BMSBATTERY

It doesn't look especially straightforward to replace (well for someone who works as painfully slowly as I do anyway )

Am in pretty deep with so much time and money invested in this project now that I can't really afford to back out of it aside from anything else. It's not the best feeling over a barrel at the best of times but that's life - and things were progressing towards a really nice outcome so keeping that in mind.

Worst case scenario is that I find £300-odd from somewhere to spend on a new motor & spokes instead and then build another wheel on arrival. Not relishing idea of that but I need to get this project finished and move on ASAP now. If I wait 10-14 days for parts from China and then a repair doesn't work I'll be into a month to six weeks delay by the time new motor arrives and is fitted. That's a bit too long for me to have that bike still off the road and be unable to ride it, to be honest.

Maybe those cables are available over here faster ? (doubt it though) .... If BMS dispatched stuff quick it would be a help as it gets here in 2 days by courier once they send it .. hey ho ...

So ideally need an honest appraisal of the damage, realistic options and what's involved ASAP. I'm confident I can get that from the experienced community on Pedelecs (and d8veh is bound to know ).

 

[JuicyBike]

Where are you Alex?

 

[jerrysimon]

A few on the forum have some of those cables. I have one but its probably too short. The DIY side of the hobby can be frustrating especially when you need/want the bike every day. Having a couple of bikes always working is the answer for me. That way I can pretty much guarantee that one will be working each day when I need it for my commute.

I have just repaired a three wire, no halls motor that had a damaged wire and that was pretty fiddly. The extra hall wires will be a challenge for sure.

One of the suppliers here will probably sell you a new built up wheel for a reasonable price I am sure.

Keep at it. Once built, going down the DIY route means you can always be sure that you can repair/maintain your bike

Regards

Jerry

 

[morphix]

Severed clean off :

View attachment 5173

Don't ask. Exhausted with all the to-ing and fro-ing over parts and bits for the basic build, with masses of work on at the moment following a very quiet January and early Feb, and took a short cut tonight trying to test the brake cutoff. Should have had the bike inverted or on a stand. Well I won't do that again.

It's starting to feel like this build is never gonna get on the road. I get one thing working and another thing breaks.. It would be a lot easier with a kit with everything you need supplied to plonk on a bike. Learned a lot but spent a fortune trying to get something nice. Inexperience has made every step of the way pretty hard.

What are my options ? I'd like a bike on the road inside 3 weeks ideally so can flog this lot on (and the drawer full of parts for extras) for what I can get for it, take a loan and buy an easy-fit kit bike or try to get the motor fixed / buy a new one. It'd need to be a 500W CST. I can realize £600+ for the bike as a MTB which leaves me about £800 down on the rest of the spend.

Can anyone help me out with outlining the options please ? Some serious decisions need to be made.

Damn, I'm sorry to hear that Alex, what an annoying setback. I've had quite a few setbacks and difficulties with my Mezzo build which hasn't gone as smoothly as I hoped. You just have to persevere if you think the end result is going to be worth it..but if you're really not happy with the big and want something very different, maybe it's time to fix up and sell on.

It's a pity the cable broke so close to the motor but surely that's fixable if the motor comes apart. Actually I may have a spare 9-core/pin motor cable and connector pair lying about in my spares draw as I ordered extra parts on my last order.. I can check if you think it's repairable, I doubt I'll use them myself on this build as everything seems to fit nicely with my kit directly over the motor.

 

[morphix]

Thanks - it's my own stupid fault. Cutting corners to try to speed things up and winding up with a whole load more work to do and serious delays likely. These things always seem to happen when I'm hurrying coz I'm over my head. An "it'll take as long as it takes" attitude is a must sometimes - have never been any good with that - unless I've got excess time on my hands lol.

Not certain about the cable - there is this on BMS website but there's no mention of the Hall sensor wires which are sheathed in the same cable which appears to exit the centre of the axle on the CST motor :

A pair of 9Pin Waterproof Male/Female Connector Cable for Motor - BMSBATTERY

It doesn't look especially straightforward to replace (well for someone who works as painfully slowly as I do anyway )

Am in pretty deep with so much time and money invested in this project now that I can't really afford to back out of it aside from anything else. It's not the best feeling over a barrel at the best of times but that's life - and things were progressing towards a really nice outcome so keeping that in mind.

Worst case scenario is that I find £300-odd from somewhere to spend on a new motor & spokes instead and then build another wheel on arrival. Not relishing idea of that but I need to get this project finished and move on ASAP now. If I wait 10-14 days for parts from China and then a repair doesn't work I'll be into a month to six weeks delay by the time new motor arrives and is fitted. That's a bit too long for me to have that bike still off the road and be unable to ride it, to be honest.

Maybe those cables are available over here faster ? (doubt it though) .... If BMS dispatched stuff quick it would be a help as it gets here in 2 days by courier once they send it .. hey ho ...

So ideally need an honest appraisal of the damage, realistic options and what's involved ASAP. I'm confident I can get that from the experienced community on Pedelecs (and d8veh is bound to know ).

Surely that motor must come apart and although it may be a challenge to solder in a new cable, it's likely not an impossibility.. do you have soldering facilities? That would seem the best course of action rather than paying out for a new motor build in your case..

If you don't feel able to do it, there's probably some on here would be willing to give it a go for you with the skills of servicing motors who fancies the challenge.. even if they're opposite end of country to you, might be worth trying for small cost of couriering the motor both ways, for a tenner or so on Hermes or Collect+

Have you tried to take that motor apart or seen any pics of what the insides looks like on the forum to see what sort of task you're facing? I have no experience in this field of taking motors apart myself, but I know others have done it, some even repairing and servicing old motors.. don't give up hope yet Alex

Yeah D8veh is the man for advice or help on a job like this, he'll be able to tell you if anyone can! Let's see what he thinks. I see you are looking for that cable pair, so I'll have a check and get back to you once I have located that pair I think I had with my last order.

 

[morphix]

It seems I do indeed have the cable pair Alex. Well I've found the female side of it anyway. I expect the male side is what you're after.. that must be around somewhere. I'll keep looking.

 

[Deleted member 4366]

That's bad news and bad luck. These things happen and make life more challenging. Was the bike powered at the time of the mishap?

I haven't done this repair yet. In principle it's easy, but in practice it's going to be very fiddly and require a bit of precision. I have a 250w SWX motor in the same condition, As it only cost £90 to replace, and it had other damage, compared with about £20 for a new lead, the owner decided on a new motor, The CST is a lot more expensive, so repair is more worthwhile.

I have four possible solutions:

1. I send you a cable and you repair it.

2. You send me the core and I'll repair it.

3. I have a BPM motor that's exactly the same size, weight, power and speed as yours. We swap wheels. and some time in the future, when I've repaired it, we swap back.

4. I come down to your house with my BPM motor (just in case)and attempt to repair it there.

The BPM motor's done about 3000 miles and has a 7 spd DNP 11T freewheel on it. The only significant difference to the CST is that CST has a cassette spline, BPM has a free-wheel thread.

Whoever and wherever, we probably need a vice to get the side-plate off the core. Sometimes they just tap off. Other times, there stuck like glue.

To get the core out of the motor is fairly easy. Just undo the side-plate screws and tap/press it out.

 

[mountainsport]

Hi Alex,

PEOPLE ARE SO HELPFUL ON HERE.

Mountainsport.

 

[Sacko]

Take the hub cover off, un-solder the old wires.

Strip, tin up and feed the rest of the existing cable through the axle and solder them back on.

Maybe best doing one wire at a time so you re-solder them back on correctly.

 

[103Alex1]

Actually I may have a spare 9-core/pin motor cable and connector pair lying about in my spares draw as I ordered extra parts on my last order.. I can check if you think it's repairable, I doubt I'll use them myself on this build as everything seems to fit nicely with my kit directly over the motor.

That's brilliant - thanks for your PM - real stroke of luck you have the replacement cable. Let's go for it - having a replacement cable likely best as the current one is damaged through being over-wound about half way up its length as well as being severed at the join. Replacing it completely probably safest.

Surely that motor must come apart and although it may be a challenge to solder in a new cable, it's likely not an impossibility.. do you have soldering facilities? That would seem the best course of action rather than paying out for a new motor build in your case..

Got soldering facilities but difficulty with the motor hub cover. I actually had a go last night after taking off the cassette to see what came off but one screw near the spline is seized defeated me with the screwdrivers I have.

The others at the edge of the plate need some sort of star shaped torx/hex thing and also have a pointy metal bit in the middle of the hole (like a moulded pin)and almost look like they've been anodized over so I'm not sure what tool you are supposed to get them unscrewed with... my multi-tool has something the right shape but it only fits the brake disc screws and is too small for these - plus obviously doesn't have a hole up the middle for an odd connection. Maybe you're supposed to grind the pin thing down or something if you want to take the plate off.

 

[103Alex1]

That's bad news and bad luck. These things happen and make life more challenging. Was the bike powered at the time of the mishap?

I haven't done this repair yet. In principle it's easy, but in practice it's going to be very fiddly and require a bit of precision. I have a 250w SWX motor in the same condition, As it only cost £90 to replace, and it had other damage, compared with about £20 for a new lead, the owner decided on a new motor, The CST is a lot more expensive, so repair is more worthwhile.

I have four possible solutions:

1. I send you a cable and you repair it.

2. You send me the core and I'll repair it.

3. I have a BPM motor that's exactly the same size, weight, power and speed as yours. We swap wheels. and some time in the future, when I've repaired it, we swap back.

4. I come down to your house with my BPM motor (just in case)and attempt to repair it there.

The BPM motor's done about 3000 miles and has a 7 spd DNP 11T freewheel on it. The only significant difference to the CST is that CST has a cassette spline, BPM has a free-wheel thread.

Whoever and wherever, we probably need a vice to get the side-plate off the core. Sometimes they just tap off. Other times, there stuck like glue.

To get the core out of the motor is fairly easy. Just undo the side-plate screws and tap/press it out.

Dave - wow, that's more than I ever expected and was braced for a 'you need a new motor' ! The Hall-controller connection turned up this morning ... right on cue (couldn't script it ... I'd have been out on a test ride this evening as that was last piece of jigsaw now brake cutoff fixed ).

Morphix has a replacement cable and is sending this to me today so that's step 1 towards a possible fix. I checked and was having a brain fry - the cable is a 9-core of which 5 relate to Hall, 3 the motor and the white is cut. It's connected to a single male plug so the hall wires split out on the female lead not this one. So the wires will just need splitting out at the end of the motor end of the male and soldering on I guess.

Confused about the spring which exits the axle - is this part of the cable or something different ? Some of it spun out with the severed cable.

Am back home now - was meant to be away all day but we finished up early. Being pragmatic, I don't have a vice here and have only basic tools so we could have a go at fixing here but might hit limitations. Trying to see if I can get the core out and at least inspect - but as above am having trouble with the tools to get it off or even unscrewed.

I explained to a member of my family what had happened and have a rare chance of a lift on Sunday so could bring the wheel / bike up to you if that was easier and you were free. Just a thought - let me know if that would be easier or do'able ?

In the meantime I guess having the motor opened up and accessible for repair seems sensible if I'm able to get that far at least. I'll do my best with what I have to try and get it that far. Any guidance on getting in to it and past those fixings would help.

Take the hub cover off, un-solder the old wires.

Strip, tin up and feed the rest of the existing cable through the axle and solder them back on.

Maybe best doing one wire at a time so you re-solder them back on correctly.

Sounds less complicated than I envisaged - am getting a new cable from Morphix as I think the old one is cream crackered inside the outer sheath. It looks identical to the one coming out of the motor that couples to my controller from the pictures so will see when it gets here. Think I might need the cable length to be honest.

Just gotta get that cover off somehow !!!

 

[Old_Dave]

Confused about the spring which exits the axle - is this part of the cable or something different ? Some of it spun out with the severed cable.

The spring is there as a protector for the cable... so that the cable isn't damaged by knocks and scuffs

 

[103Alex1]

The spring is there as a protector for the cable... so that the cable isn't damaged by knocks and scuffs

Got it - I guess also in order that the end of the axle doesn't cut or rub against the cable. It's actually just heatshrunk over the part of the cable near the axle opening - the rest disappears into the axle and must be attached somehow in there - can't see yet.

Wonder if any local suppiers carry these springs if it has to be replaced also (as not part of the cable).

I got the inner set of screws off finally - but all they do is seat the cassette spline and hold it in place. I guess it's the outer ones with the funny screw heads that have to come off ... so need to try to find out what sort of tool will undo them and what size to try to open up .

 

[RobF]

The odd shaped fixing sounds like it might be a Torx security bolt.

It can be undone with a Torx bit which has a dome cut out of the centre, like this:

Draper 38716 33-Piece Security Bit Set: Amazon.co.uk: DIY & Tools

 

[Old_Dave]

As to the spring... instead of fitting internally, maybe one of these cut down and fitted over the axle would suffice.

Don't forget to heat treat it to get rid of the doingggggggggggggggggggggg sound

 

[morphix]

Got it - I guess also in order that the end of the axle doesn't cut or rub against the cable. It's actually just heatshrunk over the part of the cable near the axle opening - the rest disappears into the axle and must be attached somehow in there - can't see yet.

Wonder if any local suppiers carry these springs if it has to be replaced also (as not part of the cable).

I got the inner set of screws off finally - but all they do is seat the cassette spline and hold it in place. I guess it's the outer ones with the funny screw heads that have to come off ... so need to try to find out what sort of tool will undo them and what size to try to open up .

Unless anyone has a busted up motor they can donate the spring off, maybe you could improvise it somehow just to reinforce that cable on the exit point against rubbing etc? Hmm maybe some very thick heatshrink or something, anything just to protect the cable flex from wear I guess would be better than nothing? But I don't suppose it will hurt to go with nothing and do the fix..I wonder if heatshrink will fit over the connector though? Might be something to consider checking on heatshrink availability before re-soldering..bitsbox.co.uk does heatshrink cheap and low cost postage charges.. I also have an account with Farnell if you need anything from there.. they do free delivery and stock all kinds of stuff, maybe springs, I can probably have it delivered to you directly.

 

[jackhandy]

You should be able to find a set of various special torx & other bits: Try your local car-parts factor, or maybe Aldidl.
My set has dozens of weird bits & has got me out of schtuck many a time

 

[Deleted member 4366]

You don't need that spring thing. It's only extra support for the wire to stop it chafing.

You shouldn't remove the screws around the cassette spline. Only remove the ones around the periphery of the side-plate and then it should pop off if you tap the other end of the axle on the ground holding the wheel.

I don't think it's unnecessary to remove the side-plate from the core because the wiring is on the other side, but you need to remove the cover from the other side that has the magnets in it. For that you need help because the magnets are very strong and keep pulling it down. You must be careful not to damage the magnets especially when putting it back because it tries to jump back on with huge force as soon as it gets close. It's easier with 4 hands.