Bafang BBSxx - fault finding and fixes

[ginekolog]

Guys so clicking noises under full power gone! Again noisless, I am happy!

And cause was?

I just bought Loctite 248 (20€/stick :| ).. crank lockrings are getting loose every 100km . Will take unit apart, replace worn small metal gear, loctite big metal gear to freewheel and loctite crank lockrings. I hope I can get rid of monthly maintenance with those steps.

 

[ginekolog]

So... Bafang has responded - there is actually four different types of grease used in assembly. I have updated the wiki with their details. Will add the MSDS sheets as well as soon as I can figure out how to get it to allow uploads of pdfs.

Cant find it on wiki. Can u post it here or link to wiki?

 

[eride]

Hi
My BBS02 stopped working after a few km's with the new 750W controller.
Any idea what's wrong before I take it apart (or dump it )

https://www.youtube.com/watch?v=HAzYpird310

 

[Lurkin]

They aren't going to tell you anything really useful anyway. The greases are proprietary and they will not supply them to you unless you are a dealer.

I can't upload them to the wiki, it won't accept pdfs.

Bafang recommended using Shimano hub grease to replace the moly grease. I used the Shimano premium grease and I think it's way too thin. It's now making a lot more noise than it was before.

TF2 Lithium grease is what I replaced the other greases with.

 

[tomjasz]

You could post the PDF here. Please?

 

[tahustvedt]

I don't think you have to worry about getting the exact same grease as Bafang uses. I use the same cheap bicycle lithium grease everywhere. My BBS is quiet. It's not an aircraft that has different temperatures, loads and other conditions that the grease needs to be adapted to. It's just a little motor with some gears and bearings.

 

[tomjasz]

Agreed, but it's still worth understanding what they specified. I know many here are smarter than the Bafang engineers, but I'd like to read for myself what their choices were. Anal-retentive IS hyphenated, no? :wink:

 

[jtrops]

As far as I know (just enough to get me into trouble in most cases), you do need to be aware of grease incompatiblity problems. When I installed my kit I saw what looked like Moly greeas in the final drive gear (near the freewheel), and what I think is Polyurea grease in the bottom bracket. One of the problms that I know of with combining Lithium and Polyurea grease is that it will cause the grease to liquify, and result in the lubricant vacanting the bearing surfaces. This leads to premature wear. So, if in fact they are using Polyurea in the BB you really wouldn't want to replace it with Lithium unless you thoroughly cleaned out the old grease first. If you start with clean parts Lithium should be fine.

Unfortunately without good information about what lube is being used it is hit or miss guessing on our end. It would really be good if Bafang would tell us exaCtly which lubes they are using even as far as brand and type.

On a side note, in my kit the BB was packed with grease. Along with the improved dust seal, the abundance of grease is a good sign that Bafang is listening to feedback.

 

[tomjasz]

I asked lurkin for the pdf, but NO joy.

 

[jtrops]

I sent lurkin a PM offering to convert the pdf into an image file. We'll see...

 

[eride]

Hi
My BBS02 stopped working after a few km's with the new 750W controller.
Any idea what's wrong before I take it apart (or dump it )

https://www.youtube.com/watch?v=HAzYpird310

I need some help here pls
So tried to operate the motor with a throttle today

https://www.youtube.com/watch?v=2yOt6ufxH2g
https://www.youtube.com/watch?v=GGlOc8n2vRY

any ideas? do I have a broken motor, controller or? how can I check?
if motor windings are the problem then it's not possible to repair/replace

Its bought in 2013 as a 48v 500w (ser. no. 1310315553) no warrenty anymore and the chinese seller dont answer anything so no solution there. I have less than 500km total on it. 1 controller and a C961 LCD broke down and was changed (to 750w) and it ran nicely for another 20-30km and now this

 

[opperpanter]

Hi
My BBS02 stopped working after a few km's with the new 750W controller.
Any idea what's wrong before I take it apart (or dump it )

https://www.youtube.com/watch?v=HAzYpird310

I need some help here pls
So tried to operate the motor with a throttle today

https://www.youtube.com/watch?v=2yOt6ufxH2g
https://www.youtube.com/watch?v=GGlOc8n2vRY

any ideas? do I have a broken motor, controller or? how can I check?
if motor windings are the problem then it's not possible to repair/replace

Do you have warranty and can you send it back?

I have no idea what it is, but I think I've seen a video before of a similar problem.
Although it sounds mechanical, in that case I believe a new controller fixed it.

 

[keithwins]

I'm doing a sloowww build of a FS Bafang 750W on a Diamondback Recoil. What I noticed as I started mounting the motor into the fram is the bottom bracket if is loose/has play.That is, as I slide the Bafang into the BB, it has some play (which I would expect, given the design. Now, I could tighten down on the BB nuts, but it seems like the wrong way to go about this (that is, the torque of pedaling has me expecting minor movement over time, almost no matter the tightness). I'm thinking of wrapping it in a very thin layer of either UHMW polypropylene, or aluminum (tempered flashing). I wonder if anyone has done anything else to take out some of that play?

 

[jtrops]

I'm doing a sloowww build of a FS Bafang 750W on a Diamondback Recoil. What I noticed as I started mounting the motor into the fram is the bottom bracket if is loose/has play.That is, as I slide the Bafang into the BB, it has some play (which I would expect, given the design. Now, I could tighten down on the BB nuts, but it seems like the wrong way to go about this (that is, the torque of pedaling has me expecting minor movement over time, almost no matter the tightness). I'm thinking of wrapping it in a very thin layer of either UHMW polypropylene, or aluminum (tempered flashing). I wonder if anyone has done anything else to take out some of that play?

I know what you are talking about (I think), and once it is tightened it shouldn't move around. The gear box on the right side has a very slight chamfer to eliminate a potential stress riser. This also causes the right side to center in the BB shell. As long as your BB shell has parallel faces, tightening the lock ring will center the BB in the shell. The motor mounting bracket has teeth on it that lock it into place as well.

All said it would have to be fairly loose in order to move around. I will take mine apart in a month or so just to have a look in there, and see if it needs any initial maintenance (to get rid of swarf due to wearing in new gears and such).

 

[Lurkin]

I used a section aluminum can to help protect the threads and then wrapped plumbers tape around the Bafang spindle. Makes for a snug fit. I greased both sides of the can section so it's easy to slide in and out.

This also served another purpose - to detect if the Bafang spindle damages the threads by moving once tightened under extreme load. I was not convinced that tightening the lockrings were enough to prevent small movements when pedaling hard, which would in turn damage the BB threads (yes, which ignored the wedge design of the spindle etc).

I have removed the unit from the bike in the last two months. There was no damage to the can or the tape after ~3,500kms, no damage to the threads in the BB. So it seems so long as the lockrings are really tight, no damage occurs. The dimpled lockring will bite into the face of your BB though. Unavoidable damage. When reassembling mine I have continued to use the aluminum can section and plumbers tape as cheap insurance and a diagnostic going forward.

There will not be any swarf from 'running in' the motor, so long as it has been adequately greased inside and the inner motor shaft o-ring has not lunched itself. If I was to do it again, I would disassemble the motor on day one and check all of the greasing is adequate and conduct the loctite/o-ring 'fix'. I realise this would void some warranties, but what the hell. Whilst there was grease in mine, definitely could do with more in the crank area, which it now has.

The only area that could require cleaning/regreasing is the needle/thrust bearings in the crank and the "moly" (which no, is NOT moly grease) grease on the large reduction gear. Neither area is totally waterproof or surrounded sufficiently to avoid water contamination after heavy rainfall. The crank area was lacking in grease to start with and the reduction gear grease and small particles of dirt/crap in it. This is only after a period of heavy rain and heavy usage in the rain.

I will get round to posting up the grease docs from Bafang when I get time. It's end of financial year at the moment and thus the busiest time for it. I will do it when I have time, not when 10 people send PMs for it. If you bothered to read what I have previously written, rather than sending PMs, you would realise I am already on to it. Further, there are interesting results as to the greases recommended on ES, Bafang and the MSDS docs received. This will all be detailed (eventually) in the wiki, not in this thread, as previously disclosed. It makes more sense to have a central place to go, rather than trying to string together bits and bobs throughout multiple threads.

I am considering updating the original thread I started for the bike I have fitted with one of these units. It will pretty much end up being a high km's test thread given it's being used to commute 80km per working day.

 

[keithwins]

OMG Lurkin you're the best. That's just the kind of thing I would have done, or would have thought about doing, or would have wished someone did. Awesome. thanks so much for that. Can't wait to read the wiki. It's so great to get these kinds of answers so readily. Okay, I'll stop now.

 

[tomjasz]

I will get round to posting up the grease docs from Bafang when I get time. It's end of financial year at the moment and thus the busiest time for it. I will do it when I have time, not when 10 people send PMs for it. If you bothered to read what I have previously written, rather than sending PMs, you would realise I am already on to it. Further, there are interesting results as to the greases recommended on ES, Bafang and the MSDS docs received. This will all be detailed (eventually) in the wiki, not in this thread, as previously disclosed. It makes more sense to have a central place to go, rather than trying to string together bits and bobs throughout multiple threads.

I am considering updating the original thread I started for the bike I have fitted with one of these units. It will pretty much end up being a high km's test thread given it's being used to commute 80km per working day.

Some of us PM'd willing to help get the docs up. Oh well...

 

[ginekolog]

I finally took unit apart and replaced small metal gear. Gear was totally deformed, see pic. Gear was greased.

Unit is quiet again just like new. Perfect. It took me 3,5h to take every thing apart, regreased and loctite (248). I used silicione grease (for scuba o-rings) for nylong gear and green lithium grease for metal gears.

I hope new gear dealer send me is better quality and it wont wear out in 1500 km. I also noticed that loctite on crankshaft (2 lockrings) is MUST. Design is poor in this area because it's not possible do counter tighten lockrings.

Left new gear, right worn out, making grinding sound when pedaling (and minor grinding sound when motor was working)

Hi Guys,
https://youtu.be/e-qjojAQPzM
Is this something normal and I am too paranoid or this is something wrong with the motor?

Thanks!

My first post on this interesting community.. hi all

I have similar noise as you when pedaling. With motor power is quiet. It was quiet on begining also when pedaling. I took unit apart and found reason for noise: small metal gear( that is driving big gear ) looked fine on sight but when I tocuhed it found problem. Edges of gear teeth are sharp and worn. Thats why gears make noise because when you pedal faster than motor, other side of gear teeth touch and make noise. Grease was good in all areas.

This gear is failing:
http://www.greenbikekit.com/accessories/bafang-8fun-spare-parts/bafang-8fun-mid-crank-kit-bbs01-bbs02-iron-gear-replacement.html

I have unit 4 months with 1000km, its dated 2014-10. I ride it hard offroad, big uphills with 30% grades and on somtimes on full power . My dealer said that gears are not coverd by warranty and are considered consumption material . It seems to me unit is not designed to withstand full power for too long time.

I love riding it, it gives me superb climbing power + 52 km/h on flats. GREAT fun, bike is only 22kg. But i did not think it would worn out so fast.

For now I will not change gear.. thinking gears will adapt to eachother and wear will stop. Is it possible? If not, I will change it.. from link above it seems bafang made version2 of gear.

 

[dbIsMe]

Wow!

Was there any metal/filings you had to clean out?
Also, what about the large cog? Was it OK?

 

[ginekolog]

I didn't find metal fillings. Large cog is fine (just minor wear visible).

I will inspect again soon to check for grease and wear. After ~ 300km everything is still quiet.

 

[DaDo.Bzz]

Also here cracking noises while pedalling. Do u have guys some links where I can buy small gear? Pref. with shipping to Europe. Thanks

 

[snowranger]

http://www.greenbikekit.com/bafang-8fun-mid-crank-kit-bbs01-bbs02-iron-gear-replacement.html

 

[NFN01]

Hi

I've found a way to disable PAS mode and a way of preventing the silicone seal in the crank from being squeezed out/damaged.

During BB dis-assembly to perform a are-lube I did two things.
One was to remove the encoder disc fitted behind circlip on back of the 68T freewheel gear.
This was done to physically disable the PAS mode operation leaving me with 9 power levels of throttle assist. I don't use PAS mode as I don't like the
way it works. Using the throttle only gives me control of when and how motor assist I use.
Removal of this disc which has a circular magnet bonded to it means that there is nothing for the hall effect device on the PAS sensor
to detect when the crank is rotating. Therefore the motor does not start/run when you are pedalling.

The other was, when re-assembling the crank into the BB tube. I fitted a thin locking ring and set the tension on the thrust bearings.
I fitted a second thin locking ring and tightened it against the first locking ring, I re-adjusted the trust bearing tension.
I then fitted a washer followed by the silicone seal and then a second washer.
Finally, I fitted a third thin locking ring and tightened it to compress the seal.
When looking the BB from the lock nut side it looks no different than it did with the original configuration.
I have done about 70 miles with this setup and there are no signs of anything loosening.

I have two spare sets of cranks, thrust bearings, needle bearings, lock rings,
washers and silicone seals, which made the above possible.


I hope these two tips are useful.

N

 

[Lurkin]

Paul of Em3ev is now selling a seal to go in the end of the crank, to be a more effective seal.

 

[Alter]

I have about 200mi on my BBS02, and I just noticed a pulsing in the PAS where I feel a pulse of boost on the downstroke with the right peddle. I don't notice the left peddle being any more difficult, so it seems there is still power throughout the cycle, and the top speed seems to be the same for any particular situation. Wondering what I might look for when I get around to tearing the motor down.