Bafang BBSxx - fault finding and fixes

Thanks for your detailed answer Kepler. I took apart the motor as you suggested and saw what was inside. That's about all so far. I did just go back and read the start of the thread. It didn't make sense before as I had to break open the motor and see the parts my self to see what was meant by 'non drive side' etc. The good-ish news is no massive broken bits as far as I can see. The following video shows my findings. I realise this must be really frustrating for you to watch as you know so much about these drives and I am such a novice! I cant work out how to get the cover off to remove the nylon cog, that's tomorrow's task. I had no O-ring and I now see why you would loctite the bearing! When I read it first I was like, "wont that stop it spinning?" HA I see now the reason.
Here's the stage I am up to.
http://youtu.be/YvNELzoklDE
 
To get the cover plate off of the space where the nylon gear is, you need to use machine screws in the adjacent holes to "jack" out the cover. I believe there are three holes for this. Be sure to jack each hole location evenly so the plate comes out parallel to the face of the housing. (You don't want to jack just one side all the way out or you'll bend the plate)

You should then be able to remove the retainer clip and the nylon gear and inspect the assembly.
 
You have done really well aniken getting it to this stage and documenting as you go. Just follow teslanv's instruction to remove that cover. You will kick yourself when you see how easy it comes off using jacking screws.

I am quite intrigued with what is going to be the final outcome. Once you get the cover off and the nylon gear removed you will be able to check both supporting bearings and the nylon gear's sprag bearing. Make sure it free wheels in one direction and grabs the intermediate shaft in the other direction.

The wear on the primary gear is of concern but I need to see a better picture of it. Please take a high res photo of the worn area and post up. I resume you have a vernier caliper. Please measure the shaft journal sizes as accurately as possible.

I think going by the evidence to date, it may well be there is too much wear between the the primary gear and the secondary plastic gear. You may find a collapsed bearing has caused this wear.

Anyway, remove the secondary gear reduction cover will reveal all.

That black goo looks wrong too as the grease in this part of the drive is white lithium grease. It maybe that grease and debris from a collapsed bearing has mixed in with it.

Anyway, enough speculation. The final part of the disassembly should reveal all.
 
skuutti said:
Ok. So I fixed the bearing problem. I removed the ball cages from the bearings altogether and filled the bearings with additional balls (6 x 3,2 mm diameter).
Click for picture
Then I made a new rubber seal to prevent water and dirt from getting in.
Click for picture

But unfortunately this didn't fix the problem!
I made a video that demonstrates the problem. At first I tap the throttle (Assist level 1) against rear brake. It makes the click every time I do this. Then I simulate what happens usually when I drive. I stop pedaling and the motor turns off, when I start to pedal again it makes this click like there is some spring loaded and it releases when I touch the pedals.

Remember! This only happens when riding in PAS-mode. When I ride without the motor it doesn't happen and when I ride with only the throttle it doesn't happen!
[youtube]4X3RCYICcSQ[/youtube]
Click to expand...

Great news! Yesterday I finally received the new nylon gear that includes the clutch. Today I put the motor back together with the new gear and this fixed the clicking problem displayed on the video!
I can still feel a slight click in the pedals when I start pedaling (the clutch releases), but it can't be even heard.
I used CRC silicon grease on the plastic gear. It seems to have made it even quieter than before. Almost dead quiet now!
 
Gab said:
So much for this being a quiet kit , it seems its only quiet for the first few hundred km's and then all this clicking and popping noise start ?? some of the videos have a very loud noises and they say the cyclone kits are noisy !! this is even worse when these things play up ands near damn near impossible to fix so many custom gears and parts.
Click to expand...

I have to say that you make a good point. This kit has been around for few years now and they have already made a lot of improvements. But still my unit (manufactured 3/2014) lasted only 300km before it needed parts replaced. I didn't abuse it or anything.
 
I would never have thought of jacking screws! Didn't even notice any extra holes!

I had a night off to go watch the first nocturne cycle race meeting in my town. I just spent all evening wondering, "could I win if I was on my EB!". It was really cool lots of sprint finishes, crashes and a 'course crasher' on a big wheel unicycle during one of the races! I think he got the biggest cheer of all the riders there.

The black goo in my video is my doing :oops: I sprayed all manner of oils and potions in there to try to fix the scraping noise before I took it apart. Looks like I went a bit OTT but I couldn't tell how much if any was going in so I used plenty!

I will do another video tomorrow hopefully with the final part of the tear down.

I will measure some parts and try to photograph what I believe is wear on the main drive shaft. Obviously I have no point of reference though having not really seen another motor other than via videos on here, maybe they are all like that?
 
Okay so here is the final (I hope) tear down video. I would like to know if what I have found is normal or not please. Also hopefully you should see below the photo's of the helical part I think has some unusual wear on it. I think it shows it quite well. If you look at the mid shot although there is wear the right hand end seems to have accelerated & localised wear when compared to the rest.

Video: http://youtu.be/SThP7r_QCoA

This Is what I am calling the unworn end and looks like new.



This is a mid shot of the drive shaft.



This is a shot of the end that looks a bit chewed to me?



 
Yes, that gear is REALLY chewed up. Mine was in near pristine condition when I had to tear it apart. It had about 500 miles on it at the time. You have a problem in your secondary gearset for sure. What does your nylon gear look like? If you compare your parts to the photos I posted on the first page of this thread, you will see what mine looked like.
 
LET THIS BE A LESSON TO YOU ALL, DONT IGNORE NOISES!
You have to see this video!
Little help??
[youtube]Dw2wNuyzOgI[/youtube]
 
teslanv said:
Yes, that gear is REALLY chewed up. Mine was in near pristine condition when I had to tear it apart. It had about 500 miles on it at the time. You have a problem in your secondary gearset for sure. What does your nylon gear look like? If you compare your parts to the photos I posted on the first page of this thread, you will see what mine looked like.
Click to expand...

Yah I cant believe a metal gear has worn so much when it runs on a nylon one. If you look at he video above the pictures I show the condition of the nylon cog. Its not too bad, doesn't look chewed up like this one? What I dont show is them meshed together. I tried this and they fit together really well! I am definitely going to try to reuse them due to a total lack of spares in the UK AFAIK although I will investigate this because as soon as I got the bike built a year ago I kind of disappeared from the forum to happily use the bike and enjoy my life! Maybe a year on there are some uk distributors that carry spares and maybe pigs ride flying E-Bikes!
 
Glad you finally got to the bottom of the problem. The gear has some nasty damage but I think it will still be serviceable once you replace the bearing.

Anyway keep us up to date with how the repairs go.
 
Everbody seems pretty cheerful about the seemingly endless issues that crop up with this system. At what point does the average person who just wants a reliable ebike consider this system to be POS? I almost bought one last week but changed my mind at the last moment and substituted a battery pack from bmsbattery instead.
 
chvidgov.bc.ca said:
Everbody seems pretty cheerful about the seemingly endless issues that crop up with this system.
Click to expand...

This is a case of no news is good news, we only hear about the problems on this thread, don't hear from the hundreds if not thousands of people who are not having problems.

This is a new product and is bound to have teething problems. I think the basic consensus it that these drives are well designed and that the manufacturer is improving the units and ironing out the bugs.

As an early adopter I think you have to accept there is more of a chance of something going wrong. Hopefully if you purchase the drive from a local reputable supplier they would fix any problems under warranty or if the drive is out of warranty would have the spare parts and expertise to fix the faults and this would be backed up by the manufacturer.

If you purchase the units from China I think you have to expect to be able to fix the problems yourself. At least it looks like you can get some spare parts for the units from China, hopefully this list of parts will grow with time.
 
Thanks aniken for you videos and commentary, I have found them very interesting.

You mention that your drive powers down by itself on occasions. I wonder if this isn't being caused by the "sleep" function causing the unit to shut down after inactivity. The drive might detect activity as being motion detected by the external motion sensor. If you run the drive without the external sensor detecting motion the unit might shut down, just a thought.
 
Re: Bafang BBSxx - fault finding and fixes

by skuutti » Sat Jun 14, 2014 12:38 pm



Gab wrote:So much for this being a quiet kit , it seems its only quiet for the first few hundred km's and then all this clicking and popping noise start ?? some of the videos have a very loud noises and they say the cyclone kits are noisy !! this is even worse when these things play up ands near damn near impossible to fix so many custom gears and parts.


I have to say that you make a good point. This kit has been around for few years now and they have already made a lot of improvements. But still my unit (manufactured 3/2014) lasted only 300km before it needed parts replaced. I didn't abuse it or anything.
Click to expand...

This is an interesting point, as this was the only advatage this bafang BBs02 kit had over the cyclone type mid drive kits , i.e that it was more quiet, but if it can only maintain this low noise for a few hundred Km's due to problems then it may not be worthwile , As the BBS02 also has it's major disadvatages that its a lot more complicated and hard to service internaly . Also due to the complexity and helical gears its less efficient then single planetary stage strait cut gears of the cyclones.

Also the life span , people have shown cyclone kits on the sphere that have done above 10,000km which i think is very unlikely with so many problems with so little kms on the BBs02, unless you do a majour overhall on them every few thousand km it seems.
 
2500km and my drive is still as quite as the day I installed it. Sure, it's been pulled apart 3 times to keep it that way but who's counting : :lol:

Your point is valid and I have no argument against what you are saying. I do believe however that as the drive has matured and many of the early problems now ironed out. Not much consolation for the early adopters but quite often that's the way it goes for people who want the latest and the greatest. Personally I don't regret purchasing this drive for 1 second, rebuilds and all.

I got to say though, I see a few cyclone conversions on my commute and I can hear them a mile away. They might be durable but the racket they make is such a deal breaker for me personally.
 
chvidgov.bc.ca said:
At what point does the average person who just wants a reliable ebike consider this system to be POS?
Click to expand...
Why would you expect a thread titled, Fault finding and Fixes to extoll the virtues of a system? Common sense dictates you'd find problems here, not those of us with BBSxx units that are running flawlessly and daily. Nice list of rides BTW!
 
Kepler said:
I got to say though, I see a few cyclone conversions on my commute and I can hear them a mile away. They might be durable but the racket they make is such a deal breaker for me personally.
Click to expand...
Thanks for that, I was about to ask why you weren't enamored by them.
 
simat said:
Thanks aniken for you videos and commentary, I have found them very interesting.

You mention that your drive powers down by itself on occasions. I wonder if this isn't being caused by the "sleep" function causing the unit to shut down after inactivity. The drive might detect activity as being motion detected by the external motion sensor. If you run the drive without the external sensor detecting motion the unit might shut down, just a thought.
Click to expand...


Thanks for being the only one to address this annoying issue. To be honest as I am sure you can see I have 'bigger fish to fry' at the minute as the unit is reduced to its component parts! I did try to explain this annoyance about a year ago without anyone else having the problem.

From what I can tell when you use the throttle it blocks the signal from the pas (pedal) sensor so the controller or display or whatever 'sees' rider inactivity (or doesent detect 'rider activity' to put it another way.
It seems throttle signal doesn't count as 'rider activity'. This starts the "sleep countdown".
If the controller or display or whatever doesen't get a pedal signal to tell it activity is happening within the alloted sleep countdown period then when the external sensor (speedo) stops giving its signal, the unit turns off. -Phew
Thats what is happening to the best of my knowledge.

In addition the walk assist doesn't work and never has. Well unless you walk at 35 kph! Walk assist = full throttle or at least really fast! Doesn't bother me as I dont use it but could be related. Sometimes I wonder if the controller is programmed for the display I have! Speedo works fine though and is set up for correct wheel size and reads correct.

In short
 
How I removed the outer bearing shell from what was effectively a blind hole. I am sure there is an easier way... but I couldn't think of one so I did this!
[youtube]ZJsySWVZSKY[/youtube]

Details of the bearing and more for the benefit of other users.
[youtube]gfoI29lsSbQ[/youtube]
 
Nothing wrong with that method of bearing removal. Nicely done. I think you find the process of fault finding and repair followed by a perfectly functioning drive again a very satisfying experience.
 
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