BBS02 Makes clicky/knocking noise under load

[Swing Ninja]

So my bafang BBS02 makes clicky/knocking noise under load with or without the motor on. Please see the video below. It only happens when it's ramping up. But after at a certain speed (around 8mph+), the clicking is gone. What I've tried so far:

1. Throttling while parked, with no load. Everything is fine, no clicky/knocking noise.
2. Pedaling with hand while parked (no load). Also fine.
3. Make sure the chain lined up. The chain never came off.
4. No wear and tear on sprocket and chainring.

So I think it's something to do with bottom bracket. Any advice before I start dissasembling or is there anything else I should look at? Is it really the bottom bracket? This is my second e-bike I built (with same motor and battery if that matters). Thanks.

ebike video link

 

[rich c]

There's no true bottom bracket left with a BBS02 is there? Knocking noise can come from loose cranks, loose pedals, and even a loose saddle since your butt is rocking back and forth while pedaling.

 

[Swing Ninja]

It's the part that goes into the bottom bracket area. Kinda like what's shown in this video. I've opened up the motor before, but just to put some moly grease.

 

[tomjasz]

Clutch is functioning? https://electricbike.com/forum/foru...and-kits/bbshd/22903-bbs02-clutch-replacement

 

[Swing Ninja]

Thanks for the link. That helps a lot in investigation. I kinda suspected there's some sort of internal gear change mechanism, because it sounds like my 90's car automatic transmission switching gears. It only happens when I ramp up/throttling up the motor.

 

[iitsuka]

I have the same noise that has started to happen, under the same conditions. Checked all the internal parts (gears and clutch) and can not find any issue. Did you figure out what it was?

 

[tomjasz]

I have the same noise that has started to happen, under the same conditions. Checked all the internal parts (gears and clutch) and can not find any issue. Did you figure out what it was?

you are asking in a thread that is 4 years old! To often posters come for help and once sorted don't give back or update their success or failure.

Swing Ninja​

New Member · From Oregon
Joined Jul 29, 2019
Last seen Aug 20, 2021

 

[iitsuka]

yes maybe they will respond? i can't find online any solution and this is the best video of what i'm encountering, there is another video by someone else with the same issue but no resolution.. hoping original poster or someone with that encountered the same issue can provide their experience

i tore the motor down again today and noticed some rubbing of the main pinion gear against the housing, noticed it as i cleaned all the grease to put in fresh grease.. the rubbing is about 25cm long and on the 7:30 area of the housing and slightly only on the outer edge of the back of the pinion gear.. my MTB fram is made of out Ti and flexs alot during load.. i think it might be that the pinion gear is binding under load when the chain adds resitance against the chainring then transfers a small deflection to the pinion gear causing the binding.. i think the solution is tightening the internal nut on the mid drive shaft.. have to get the tool to tighen it, it was not tight when i took it apart, used needle nose pliers and unable to torque it tight without the right tool.. so i think that is the issue..

 

[Mike_V]

yes maybe they will respond? i can't find online any solution and this is the best video of what i'm encountering, there is another video by someone else with the same issue but no resolution.. hoping original poster or someone with that encountered the same issue can provide their experience

i tore the motor down again today and noticed some rubbing of the main pinion gear against the housing, noticed it as i cleaned all the grease to put in fresh grease.. the rubbing is about 25cm long and on the 7:30 area of the housing and slightly only on the outer edge of the back of the pinion gear.. my MTB fram is made of out Ti and flexs alot during load.. i think it might be that the pinion gear is binding under load when the chain adds resitance against the chainring then transfers a small deflection to the pinion gear causing the binding.. i think the solution is tightening the internal nut on the mid drive shaft.. have to get the tool to tighen it, it was not tight when i took it apart, used needle nose pliers and unable to torque it tight without the right tool.. so i think that is the issue..

Hi Suka,
I'm glad You got a rise out of of Mr. TOM because I read about the noise you encountered with great interest because I know there is no follow up from most original posters but I'm glad you have written: I too had a puzzling clicking noise late last season, which I ignored and just plain throttled on (period)
Upon teardown this Spring I was really quite surprised to find one (or two) loose crank arm.
My only comment: you've checked everything, so bolt it down, grease it up listen to the birds and Ride on, it's just a noise.
Good Luck
Mike

 

[iitsuka]

Think I may have found the issue. Frustrating to figure out what is causing it. Rode it today and noticed when under PAS when the noise occurs the pedals had no resistance for the split second. But it happens when on throttle only and pedals not moving. I've eliminated the drive train (chain, sprocket, chainring and hub), given that it occurs even without the pedals moving, it can't be the regular clutch.


So I tore it down one more time, wanting to look at the nylon gear as it has one way bearings that effectively a clutch. Nothing looked out of place, the nylon gears all there, the bearings all there, then checked each one way bearing to see if they moved normally, a couple did not more that freely as others, so kept on looking and found a very small damage to the cage the one way bearings sit in. I think its interfering with the bearing fully seating and locking the nylon gear to the pinion shaft causing the skipping. Whatever caused the damage might have sent small pieces inside the other one way bearings making them "stuck or sticky" in their function.

Ordered a new nylon gear, crossing my fingers this solves the issue. Hoping this is it, it only happens under load, so i think the one way bearings are not fully seated causing the skipping. Really challenging to solve this issue.

Here is a picture, so hard to see the small damage

 

[gromike]

Yeah, something hard went through those rollers. It's probably been chewing on the pieces of metal from the cage for awhile.

 

[iitsuka]

Put in new nylon gear and still have same issue.. it’s either slipping still or power coming on and off suddenly.

Think I’m done trying to figure this out, will be taking it off and throwing it in the garbage. Will go back to human power or might try hub motor next time. Got to say bafang is a very low quality and poorly designed option, not worth it.

 

[tomjasz]

Put in new nylon gear and still have same issue.. it’s either slipping still or power coming on and off suddenly.

Think I’m done trying to figure this out, will be taking it off and throwing it in the garbage. Will go back to human power or might try hub motor next time. Got to say bafang is a very low quality and poorly designed option, not worth it.

too funny. You can't sort the problem and now it's Bafang that's the problem. I've owned 8 BBSxx series and sold scores, and still ride two from 2014.

 

[iitsuka]

Thank you for your insightful help on this

Yes I can not figure it out, appreciate all the help you have provided to aid in my efforts