Bafang BBSxx - fault finding and fixes

[tomjasz]

From Doug in my archives.

All bearings should be clearly marked as to industry standard numbering. So when you tear down a motor, any bearing that is suspect of damage can be replaced from local sources using the bearing number written on the bearing. One exception is the ball thrust bearings which are proprietary to Bafang. I've never been able to source these bearings elsewhere.
Here is what I have for the moment.
motor
2 motor shaft bearings These will be 628 bearings on both ends unless you have the latest version with the heavier rotor shaft. Then one of the bearings will be a 629 bearing.

Gears
1 bearing in the steel gear cover
1 pinion pressed-in case bearing
1 nylon gear/pinion cover plate bearing 16001
Nylon gear (built-in) needle bearing This is a clutch bearing HFL1626

Axle
1 44mm axle bearing
1 axle needle bearing NK17/16
1 three-piece roller (or thrust) bearing Nonstandard proprietary to Bafang

I hope this helps. We do not have any HD's open for repair at the moment so I have not been able to get more information.

 

[petersv]

Thanks guys. I have an BBS02B, not an HD, is is still the 16001 I need? The listings I posted, with the two different bearings, I must admit I don't understand which one I need of the two. The second says 16003RS and that it's for the "Axle"?

 

[SUPERJC]

Thanks guys. I have an BBS02B, not an HD, is is still the 16001 I need? The listings I posted, with the two different bearings, I must admit I don't understand which one I need of the two. The second says 16003RS and that it's for the "Axle"?

if it can help...

 

[fechter]

if it can help...

Great picture. Thanks for posting. Is that a BBSHD or BBS02?

 

[petersv]

if it can help...

Fantastic. The image didn't load here on the forum, but I can see it accessing the URL directly! Thanks

 

[petersv]

So I opened it up again, this time a bit further. Here are my findings:

- The image posted seems to be for another version of the motor, for the BBS02B the bearings are different.
- The pinion gear seems to be quite corroded and also not smooth at all. Maybe I should replace it?
- The nylon gear with the internal one-way rolling bearing is also not in great shape (the bearing), should I replace both of these?
- The retaining clip under the nylon gear was split, seems to have been spinning before it broke. Might be the remaining part that I heard the noise from?

Apart from that it doesn't look *that* bad, all things considered. What would you do, replace all the bearings, nylon and pinion gear? I don't see how I can remove the bearing that is on the tip of the pinion gear (at the bottom of the case, pressed in), is this possible?

View attachment IMG_20220503_145902.jpg

 

[petersv]

Here is a good reference for the bearings as well. https://electricbike.com/forum/forum/knowledge-base/motors-and-kits/bbshd/22943-bbs02-version-b-internal-parts-pictures

 

[petersv]

I ended up ordering the pinion and nylon gear, plus the plate with the bearing. We'll see if that helps.

 

[petersv]

So, finally all the parts arrived, and I have changes the bearings (also the one in the nylon gear) and the sound is gone. Salt is what killed them it seems. It must have passed from the bearing on he pinion gear and into the rest of the motor.

 

[tomjasz]

Get some ACF50 or Boeshield. Next some high quality black RTV. Treat everything you can with the first two and then rub in the RTV TO EVERY CRACK AND CRANNY on the exterior of the case.

 

[petersv]

Not sure if I understand. The water entered from the secondary gearbox (under the plastic cover,) and through the bearing that holds the pinion gear in the case, and into the motor. I don't see any way to prevent that apart from using better/stainless bearings.

 

[donter]

In need of help to get my bbs02b back up and running again.
Recently the 21H error popped up on my display, meaning the malfunction of the speed sensor. Also my 6V LED lights stopped working (most likely I was overloading the controller using my lights since they draw 1 amp total). Upon inspection of the speed sensor cable, I get a steady 5V ground to positive, but only 1.3V ground to signal, supposed to be approx 5V as in this diagram.


I tested the speed sensor cable by shorting the ground to the signal but no speed reading showed up on the screen. Upon inspection of the controller pcb, a hole was burnt through the pcb (cleaned up for the photo and desoldered the 6V light module):


The solder blobs are left by me before I soldered a small wire through the burnt hole to the other side of the pcb:


Soldering the wire through the pcb did not help, still getting a low voltage on the speed sensor cable from signal to ground. Based on a photo of an older model bbsxx board I found on the web, the hole was burnt through the two dots I marked with an orange arrow. I have the wire soldered through the pcb to the area pointed with the blue arrow, so that is probably not where it is supposed to connect.



If anyone can help me with this situation I would be greatly thankful.

 

[fechter]

I’ve seen the orange zener diode short out and take out the 5v line. Test all the diodes with a meter and look for shorts.

 

[donter]

I’ve seen the orange zener diode short out and take out the 5v line. Test all the diodes with a meter and look for shorts.

Thank you for the reply. I have checked the closest diodes by desoldering them and they seem fine. After soldering them back I got the proper voltage back into the speed sensor cable. Now the speed sensor works like normal again Not sure how and why. But I still don't have the 6V light output from the converter module. Is there any simple way of testing the 6v light module removed from the controller?

 

[fechter]

With it installed, you could try measuring the voltages on the pins. I've never used that 6v light output, so not sure how it's configured.

Plan B would be to use a separate dc-dc converter for lights.

Can you tell if the controller is working now? Does the motor run?

 

[donter]

Yup, probably a more sensible thing to do is to install a separate converter for the lights but I liked the control of the lights through the lcd, that's why I want to restore it. The controller works as before, the only issue was the speed sensor (now resolved) and the 6v light output.

 

[donter]

Hoping to find if anyone can point out to what component the voltage regulator leg connects to on the other side of the board since mine is burnt through.

 

[amigafan2003]

Question for the hive mind.

I've just serviced my BBS with new grease (Mobil 28). On reassembly I appear to have forgotten to use the circlip that holds the primary nylon gear in place. I took it for a test run (before realising I'd have forgotten the circlip) and it runs fine with no odd noises. The question is, do I remove everything from the bike again to fit the circlip or do we reckon it will run ok without? Or at least until I next service it?

EDIT: Damit, it not only holds the primary nylon gear but it also holds the reduction shaft in place. So I guess without that circlip the shaft could move side to side - that would not be good :-(

 

[fechter]

Yes, you should replace the clip or else the shaft will be pushing sideways and eventually drill itself through the housing. Also the full width of the gear may not be engaged.

 

[amigafan2003]

Yes, you should replace the clip or else the shaft will be pushing sideways and eventually drill itself through the housing. Also the full width of the gear may not be engaged.

Thank you, that's what I figured out in the end.

Already replaced circlip