Bbs02b after 10000km

[ak136]

Hello,

Has anyone had this happen to their bbso2b rotor?
I am sharing pictures of a new motor and a 10000km used motor.

The burried bearing for the rotor is not seized when I try to spin it by hand

How can I prevent this from happening in the future?

Mybe the burried bearing on the other side of the rotor has failed, enabling the rotor to move side by side and then slowly eating the bearing on the casing side

Also anyone has any tips for pulling the rotor from the housing?

Thanks

 

[ak136]

Bearing on the other side of the rotor feels solid, doesnt rock side to side and spins nicely, no cracking felling when spinning with fingers

 

[ak136]

Side to side rotor movement on the casing side bearing is the same as in the new casing

 

[Johnny What]

My guess would be that sprag clutch and rollers inside nylon gear have rusted and maybe collapsed.

I say this because I’ve just had my 02 apart, not quite your mileage but close. The clutch had stopped freewheeling —I could feel motor resistance when pedalling unassisted so I bought a new nylon gear complete with clutch. I was pleasantly surprised to see nylon gear in perfect condition but rust inside was proper bad. I managed to clean up shaft and reused it but they’re cheap as chips so if you buy a new gear you may as well get a new shaft too. The question then is which grease to use on it, internet takes you to many choices, possibly ultimate is to use a different one on sprag to the one you use on nylon gear but I took a gamble on mobilgrease 28 (synthetic with clay thickener !) and used it both sides of motor, all round secondary reduction gear etc etc. Hopefully that will keep clutch lubed indefinitely!

Only a couple of weeks since I did it but it’s quiet as a church mouse and not slipping under max load nor dragging just pedalling, so far so good.

Do post back if this was issue

 

[gromike]

Man, that looks nasty on the rotors output pinion. Looks like there was no bearing operating at that point in the drivetrain, and that axial loads were carried by other components in the engine. Good thing you found it before a catastrophic failure occurred. Wouldn't want to nick your ankle.

 

[ak136]

My guess would be that sprag clutch and rollers inside nylon gear have rusted and maybe collapsed.

I say this because I’ve just had my 02 apart, not quite your mileage but close. The clutch had stopped freewheeling —I could feel motor resistance when pedalling unassisted so I bought a new nylon gear complete with clutch. I was pleasantly surprised to see nylon gear in perfect condition but rust inside was proper bad. I managed to clean up shaft and reused it but they’re cheap as chips so if you buy a new gear you may as well get a new shaft too. The question then is which grease to use on it, internet takes you to many choices, possibly ultimate is to use a different one on sprag to the one you use on nylon gear but I took a gamble on mobilgrease 28 (synthetic with clay thickener !) and used it both sides of motor, all round secondary reduction gear etc etc. Hopefully that will keep clutch lubed indefinitely!

Only a couple of weeks since I did it but it’s quiet as a church mouse and not slipping under max load nor dragging just pedalling, so far so good.

Do post back if this was issue

I dont think its the sprag, I checked mine and it looked good inside, also I tried the engagement with finger and it works good

But secondly why I dont think it has anything with sprag bearings is because then you would have to say that the sprag bearings hold the sprag and then the nylon gear holds the motor gear if you get what I am trying to say

I dont think the nylon gear is holding the motor gear, what I think holds the motor gear are the two bearings one on the casing side and one behind the rotor

Also this is very weird since I just disasembled another similar condition motor and the same thing happened, the exact same thing happened to the rotor

Is this mybe a factory thing?

 

[ak136]

Man, that looks nasty on the rotors output pinion. Looks like there was no bearing operating at that point in the drivetrain, and that axial loads were carried by other components in the engine. Good thing you found it before a catastrophic failure occurred. Wouldn't want to nick your ankle.

How would you recommend checking the bearings? Do you think my method in the pictures is okay?

What I did is checked the side to side movement with a new rotor inserted into the bearing. What I found out is there is the same amount of side to side movement when I insert the same new rotor into the used housing and the new housing

 

[gromike]

It's that the bearing surface on the motors output shaft is worn the f*ck down. The bearing that it fits into is highly suspect.

 

[ak136]

Putting locktite to solve this in the future?
And also replacing the o-rings regularly

 

[Johnny What]

I dont think its the sprag, I checked mine and it looked good inside, also I tried the engagement with finger and it works good

But secondly why I dont think it has anything with sprag bearings is because then you would have to say that the sprag bearings hold the sprag and then the nylon gear holds the motor gear if you get what I am trying to say

I dont think the nylon gear is holding the motor gear, what I think holds the motor gear are the two bearings one on the casing side and one behind the rotor

Also this is very weird since I just disasembled another similar condition motor and the same thing happened, the exact same thing happened to the rotor

Is this mybe a factory thing?

Yep, def not sprag, I was thinking of rust making whole thing elliptical and putting weird load on shaft/bearing, forget that. New bearings, sleeve over mullered rotot shaft and loctite should solve. My only worry with bearing retaining compound both sides is future disassembly, perhaps tapping the holes in the cover to be able to use cover as a puller ?
Best of luck

 

[ak136]

Yep, def not sprag, I was thinking of rust making whole thing elliptical and putting weird load on shaft/bearing, forget that. New bearings, sleeve over mullered rotot shaft and loctite should solve. My only worry with bearing retaining compound both sides is future disassembly, perhaps tapping the holes in the cover to be able to use cover as a puller ?
Best of luck

Yeah tapping like that would be great for easier future

Have you ever tried getting the burried bearing out? Do you have any tips

 

[Johnny What]

Yeah tapping like that would be great for easier future

Have you ever tried getting the burried bearing out? Do you have any tips

Not that exact one but blind bearing puller is correct tool, I have a tiny 2 legged puller and slide hammer that would probably work but without that, cheaper to buy blind bearing puller kit

 

[leo99]

I had some issue at that spot and there is a rubber silicon o ring that had broke and it started to rub. Once I replaced it there was no more noise or issues