Bafang bbs02 help

Help with my bafang motor

  • Motor not running

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  • Bafang help

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Trini

New Member
Help....

I just finished replacing my new rotor and nylon gear and pinion gear in my bafang bbs02. Motor turns on fine, but only spins inside without pulling chain and turning the rear wheel??? Everything is plugged in correctly!

Hope somebody know of this problem..
 

Thomas Jaszewski

Well-Known Member
Something is not put back right. Review your rebuild. If the motor is running, spinning and not engaging you've overlooked some detail.
 

Trini

New Member
Hi,

Thank you for your reply. I have already opened it 3 times in case I've overlooked something.. And nothing. I followed various YouTube clips making sure. There is no error on screen, but I'm guessing it's a electrical fault.. I can use throttle even though I am pulling the brakes??

I hope it's not the controller part there is something wrong with..
 

Thomas Jaszewski

Well-Known Member
Braking should stop the throttle. That's why the brakes have a switch to shut down motor. I'm confused. You say the motor runs, but does not turn the chainwheel. That would indicate something mechanical. Can you clarify the symptoms, please.
 

Trail Cruiser

Well-Known Member
Check the one way clutches if they are installed properly. There are 2 of them. One for the motor and one for the pedal crank.


Try reinstalling the nylon gear using the opposite side and that should solve the free wheeling issue.
 
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Trini

New Member
I have tried turning the nylon gear but it can only be installed one way or else the lock ring won't be able to put in place. I am using the z2 pinion gear with the G2 nylon gear (0ld one).

Before putting on the cover for the free wheel I can see that everything is turning as it should, but when I mount the chain wheel it won't pull the chain and the rear wheel?

Brakes are working sorry... I didn't pull them hard enough to activate.
 

Trail Cruiser

Well-Known Member
The grease may be preventing the one way clutch to bite. Please look at the video starting at 0.20.
Try wiping off all the grease on the pin shaft and all the grease inside the hole of the nylon gear. With the pin shaft inside the nylon gear, try spinning the pin and see if it freewheels in one direction and bites on the other direction.
 
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Trini

New Member
I did put in some extra grease before mounting it... Maybe that's issue. I will now degrease it all with some spray.. Hope it works.
 

Trail Cruiser

Well-Known Member
Careful with degreaser chemicals, it may soften your nylon gear. The nylon gear also requires special kind of grease which is silicon based. The regular grease will soften the nylon material.
 
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Trini

New Member
I used some brake cleaning spray which doesn't harm plastic, so I think I'm good.

I only have the classic yellow barring grease. I can't use that on top of nylon gear?
 

Trail Cruiser

Well-Known Member
The nylon gear requires the white silicon based grease. A lot of people have been destroying their nylon gears with regular grease.
Just use the white grease to all gears, including the metal gears to be safe.
 

Trini

New Member
Still no luck. I have checked and done all above. When throttling the pinion gear and main big wheel just snail around! And I can stop it with two fingers while throttling. No pulling power... Rotor and nylon and pinion gear can only be mounted one way... So it should be straight forward and easy. I don't understand it.
 

Trini

New Member
The nylon gear is locking when I turn it around. So that is working. Is it perhaps a wrong pinion gear I'm using. There are a few different models.. Put it plugs in nicely. Is it the main crank? Because that worked perfectly before changing the roter and nylon gear, and I haven't touched it.
 

Trail Cruiser

Well-Known Member
I think the grease prevents it from biting hard enough. I am more concerned of the petroleum based grease. It will be a wasted effort when the nylon gears turn into peanut butter. There are videos on complaints of those gears softening, these people do not know they're using the wrong lubricant.
 

Trini

New Member
Yes. I have removed all grease and still the same! I have just ordered a new pinion gear from greenbikekit. The one I have now is called z2 and have a o-ring on. My old one didn't. So I ordered the pinion called "2"

Don't know the difference, but my model is from 2015 and the old pinion didn't have a o-ring.. There HAS to be a difference in the two pinion models since they sell them.
 

Trail Cruiser

Well-Known Member
First thing, eye ball the old parts and the new parts and make sure they are the same.

Assuming that you have the correct replacement parts, then I would check the direction of the free wheel of the new nylon gear (to rule out factory defect).
Review 0.41 part of the above video. With the shaft placed in the nylon gear, it should bite when the nylon is turned clockwise and freewheels when the nylon is turned counter clockwise. And not the other way around.

If you open the cover at the chain ring side, the gear and pinion should be meshing together. The small pinion should be spinning when the motor is on. If not, then the inside rotor with it's attached pinion is not making contact to the nylon gear.

Addendum:
Count the number of teeth for the new parts and make sure they are the same.
 
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Trini

New Member
Hi,

It turns out the nylon gear bearing was mounted wrong. It was a factory fault! I'm now talking with greenbikekit about it, and they will talk with bafang about it. Hopefully they will send me a replacement.

Thank you for all your good help :)

Best regards,
 

Trail Cruiser

Well-Known Member
Hi,

It turns out the nylon gear bearing was mounted wrong. It was a factory fault! I'm now talking with greenbikekit about it, and they will talk with bafang about it. Hopefully they will send me a replacement.

Thank you for all your good help :)

Best regards,

Exactly what I thought right from the start! A factory defect, the freewheel on the nylon gear is in the wrong direction.
 
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