Bafang BPM Dirty Greasy Rusty Motor

[Scottyf]

Hello all.
Noticed of later the weather (UK), my commute and general aggressive riding style Is beating the crap out my bike. The poor thing needs a bit of an overhaul and some love. But in regards to this I've noticed a more metallic sound coming from my hub motor.

Also noticed a small wobble coming from the back wheel. Noticed when moving the wheel it was all the way round. Thought it's got to be a bearing. Couldn't be the gears or anything else. Axel is tight and running two torque arms now.

Long story short here's some pictures ...

Nice watery goodness. Lovely water and grease mixed in. Surprised it ran with all the water in it. This shows how much was inside.

Bearing for reference.

And the unsealed bearing making the noise and play.

I'll have to wait till the weekend for a full clean up and re grease.
The bearing Is pretty knackered though. The sealed bearing is ok but might be worth me replacing it anyway.
The open bearing looks worse for wear.

If anyone knows where to buy spares I'm all ears. If not I'm sure I can find something locally. As the outer races are a little battered.

Surprised they didn't use a better bearing but then again I guess there usually better sealed. Part of having a cheaper hub.

Gears and out ring look well and the windings are still a lovely copper colour once there cleaned. This is after 3000 miles at 44v 22amp.

Yeah the cable is now got a rain loop. But the damage is already done to be honest. The bearing this morning was fully battered. So I am back to riding unassisted after today. Not really an issue just takes me longer.

To be honest I'm sure I can have a ride around some local engineering firms round Birmingham and get a bit of help on it. The motor itself works perfectly. I'm suprised it still runs so well.
But the bearing is shafted and because the grease inside is now watered down its no longer doing its job.

The bearing although supports my weight and rotates its a horrible sound and if I keep using it I'll only damage it more. Then there will be metal fragments rotating round that will cause more damage.

I cleaned it up last night but it really needs a soak and a bake to get it back to new and remove the unwated grease.

So a little help from you wonderful people. What will be the best thing for removing the grease?
Cleaning up the inners?

I'd like to fit a better bearing but believe the one that is shot uses a race that the ball bearings sit in with a couple of cups that sit on top to hold the bearings in. I believe they where meant to be all one piece but maybe with the extra speed / me and the occasional curb hopping i've broken the bearing open. I'm not sure.

The bearing is then coupled to the side plate holding the freewheel cassette in place. Thats what supports the bearing on that side. (left hand side if you was sitting on the bike).

 

[full-throttle]

That's impressive!

I ride mine all year round in any weather yet never seen anything like this. Was one of the seals missing?

Anyway, I can prob help you with spares. What do you need? The bearings are all standard so check locally. I've got an unused gear assembly. Shipping to the UK would be around $40.

Degreaser would prob work ok, just check it doesn't react with the wire enamel and epoxy. Otherwise IPA would def be ok.

 

[dogman dan]

Only a few days into january, and you look to be the winner of the 2012 ugliest motor that still runs contest. 8)

But also a good excuse to just buy a new one. Sounds like you got your moneys worth out of that, and it can get fixed and be a spare for you.

 

[Spicerack]

Mmmm, goopy goodness! I'll second the vote for ugliest motor 2012!

Maybe something like degreaser- kerosene with a toothbrush, followed by detergent, wash with water then hit it with alcohol (meths) before drying.

Once all clean and dry, give the whole lot a hit with varnish- either the proper stuff or something that won't eat the insulation on the windings.

 

[Scottyf]

It still works yes... I cleaned it and used it this morning on my commute. It works but the sound is awful. I'm waiting for when I go over a bump and the last of the bearings collapse.

Does anyone know the actual bearing numbers at all on the one thats split open.

I think I've been riding in the rain most days and think its just built up over time. It still works though even with half a tonne of water in though which is what amazes me. Still Its only the bearings and a clean up that required. Everything else works. But it does explain a little bit more to as why my clutch kept stinking.

The seals do look battered though. Once cleaned I think i'll have to buy some of that nice varnish and give it a nice full coat to make sure if it does happen again it doesn't destroy anything.



Ps.
Thanks for the support and the nice messages about the ugly motor
Just keep riding it into the ground...

 

[miro13car]

When you approach curb on your ebike, do you jump it down or look for place where curb lowers?
Just trying to figure out what you mean by"agressive"

 

[Scottyf]

Jump straight off it.
Its harder to do on a 700c bike with a more relaxed geometry of a road bike but it can be done.

Possibly whats caused it to crack. Also bunny hop up curbs. But i think its mostly down to the poor roads, weather and rain with speeds around an average of 20mph.

The bike is a hard tail hybrid. So maybe i've beaten it up a bit. The rest of the bike has taken a beating too.
I peddle as hard as I can most of the time to make sure i'm working out a bit and also giving the batteries an easier time.
I'm not talking downhillnig agressive but probably road riding i do give it a good kicking.

Now has a new front wheel and disk brake as the V brake never stopped me quick enough in the rain.

 

[Brentis]

Just amazing, that puddle on the floor.
Great photos. Very large images.
Do you happen to know what pixel size you are using?
I may be under sizing my pics. 640x480.
I use Paint.
Any other programs recommended?
What is the max pic size before it turns to a link?

Thanks for sharing.
Best of luck to ya.

 

[Scottyf]

I upload them to photobucket on my Iphone and that rejig's it about a bit and gives me handy links that I can just paste on here.
Can't remember the last time I used a PC to write anything on a forum.

Sorry if they are not coming out nicly or end up being huge.

 

[neptronix]

This is why hub motors suck, unfortunately, and why i basically keep inside when it's rainy :/

If you have not seen this thread yet.. check it out. It will make you feel better about your life, lol..

http://endless-sphere.com/forums/viewtopic.php?f=30&t=34135

 

[Scottyf]

Managed to clean them up a little bit using so household goods.
Will do the petrol outside and not in the apartment.

My only issue currently is getting the old bearing that collapsed out. I was hoping to knock it out with a drive, hammer but I have nothing sturdy enough in the apartment to give it a good whack safely. So I'll have to pop it down to my friend at rftools and get him to drive it out.

I'll get him to measure the bearings as well while his there. For others and reference.

For now I'm riding unassisted and could do with the extra exercise.
Hopefully I can get it fully cleaned up and new bearings fitted since they have now fully collapsed.

 

[full-throttle]

This is why hub motors suck, unfortunately, and why i basically keep inside when it's rainy :/

As opposed to what? Walking.. driving.. public transport??

As far as assisted bicycle goes hub is potentially the most sealed option.

There's a lot of interesting info on waterproofing here

 

[nonlineartom]

I fear opening my MAC motor to find it in this state. How long have you been running this motor on British roads to get it this bad?

I've been riding through some 1 foot deep puddles with the bad weather we've been having recently and I think there is probably more water in the motor than on the road, notice any electrical problems at all with this much water?

 

[Scottyf]

Electrical wise its ran exactly the same as it always has.
Never a glitch at all. The only reason I opened it up was becasue i noticed more play in the rear wheel. this was when the bearing was on the way out.

The water has come through the axel on both sides as the seals are shot and with me running it constantly has flung the grease around it and then caused the bearing to rust and become damaged.

The bearing then quickly failed once exposed (Within 10 miles) The motor was then pushing me with no left hand bearing but still remarkably pushing me along even though the outcasing was scrapping on the actual motor.

It still works but not no way as effcient. However its quite a testament to how well it coped with the additional drag (Ie no left bearing, scraping metal and still pushing me along home) It did use up 7ah of battery by doing this when normally I would use 3amps.

Still it got me home.

I'm struggling to get the old bearing out but the rest of it, gears, clutch and windings are all perfect and a good colour despite the water and grease mix.

Couple of bearings soon to be on order locally, hopefully a better quality standard. Repack with grease after a final clean.
Then its round the holes and openings with some silicone sealent. Hopefully this will help keep the water out...

 

[richmpdx]

Whoa, that motor is ugly inside. I am surprised that the water plus whatever salts are present have not caused a short. Maybe there isn't enough electrolytes in the mud/dirty water to make it very conductive. I commute in the winter in Portland, OR where we have plenty of rain. I am running an Ezee geared hubmotor, not so different than what you are using. I have had problems with water getting into electrical connections outside of the hubmotor. However, recently I pulled the hubmotor cover and was surprised that the inside of the motor was dry and relatively clean. I don't do any curb hopping, maybe that is a factor.

Rich

 

[neptronix]

This is why hub motors suck, unfortunately, and why i basically keep inside when it's rainy :/

As opposed to what? Walking.. driving.. public transport??

As far as assisted bicycle goes hub is potentially the most sealed option.

There's a lot of interesting info on waterproofing here

You should be aware of other types of motors to propel a bike along by now. Chain drive systems could be vastly better in the rainproofing area, though they are more complex in others.

I watched that entire video and did not see a good outlook for rainproofing hub motors in it, other than 'drill holes in it because that worked for 1 guy'.

That doesn't bring much hope to me.
Seeing kingfisher's thread with 6 month old 9C's looking like they came from world war 2 freaked me out as well.
Machining a rust-seized bearing fragment after riding my MAC motor in light rain *twice* is not encouraging either.

Not keen on the idea that a hub motor is a maintenance part.

 

[Harold in CR]

Just to let y'all know, there is a waterproof or water resistant grease that could be used on those bearings. It's used for boat trailer wheel bearings. You can also, very carefully, lift the seal on those sealed bearings, and put that same grease in the bearing. Just don't fill it full. You need room for the grease to squish around, a without pushing the seal out of the groove in the bearing race.

 

[full-throttle]

neptronix,

I fail to understand how introducing a chain or belt and a couple of sprockets could help with the drivetrain being waterproof. The electrics will still have the same problem regardless of the arangement..

 

[neptronix]

neptronix,

I fail to understand how introducing a chain or belt and a couple of sprockets could help with the drivetrain being waterproof. The electrics will still have the same problem regardless of the arangement..

1) you can put a rain guard around a chain drive motor. Then the only water you need to worry about is water wicking off the chain.. and that's only if you don't have a rain guard on the chain.
2) A chain drive setup can also be an inrunner & have just one very well-sealed axle shaft instead of 2. Also, wires can be sealed to the motor.

Think about all the people with currie/eZip setup out there. Any of them complaining about their motors rusting out? I searched the web and couldn't find any complaints.

I bought one that had been ridden in the rain very frequently, early on in my eBike ventures. I opened the motor just for kicks and the thing was in great shape. Not a speck of rust. This is in the same conditions / environment that i started seeing my stator be pitted on a DD motor.. ( in Portland, OR. Where it rains practically 8 months out of the year )

 

[Scottyf]

I'm sure that if there was a better sealant or gaskets put on the motor you could avoid the water ingress.
Keeping the same design you could use a gasket around the freewheel casing and silicone where the wires go into the motor. A better rubber o ring gasket seal on the other bearing on the opposite side would work too.

An additional £5 in manufacturing and the you could use the same bearings as hopefully that would help keep water out.

 

[full-throttle]

Scotty: the RHS bearing is 6810RS (50mm id, 65mm od, 7mm wide)
Make sure the o-ring on the cover, the seal on the driveside and the silicone washer seal on the disc side are in place. It will help if the wire enters the hub from the bottom.

neptronics: chain and sprocket wear think about it (you may need to go somewhere lower in altitude or get an oxygen mask)

 

[Scottyf]

Thank you for the info on the rhs bearing!
Much appreciated. Don't suppose you know what the bearing is on the left hand side?

I done have a veneer to measure but Im taking it to an engineering tool makers tomorrow

 

[full-throttle]

6904RS (20x37x9mm)

 

[neptronix]

neptronics: chain and sprocket wear think about it (you may need to go somewhere lower in altitude or get an oxygen mask)

Um, how would chain and sprocket wear make a covered chain drive system more susceptible to water?
Am i missing a point or are you just switching the topic to find a fault with a point i made?

 

[full-throttle]

Um, how would chain and sprocket wear make a covered chain drive system more susceptible to water?

Never mind, you're right - chains don't wear any more in wet weather than in dry nor require more maintenance than my BPM hubmotor (which is zero in > 30,000km)

Argument closed