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BBS02 does not stop

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    BBS02 does not stop

    Hi guys,

    since some days I have two issues at my BBS02 750W 48V motor. I use it since approx 18 months with an Eggrider display.

    1.) A minor issue for me at the moment: the pedal resistance when the motor is switched off is remacably harder than before, interestingly not equally the whole pedalrotation but mainly at some pedal position. Maybe some greasing will help?

    2.) Main issue: when the system is on and I start pedalling, or press the throttle, the motor starts assisting as usual. But when I stop pedalling it keeps on working. It also does not react anymore to the brake switch/sensors. The only way I can bring it ot a stop ist either to switch off the display or to brake against the motor. When I finally stop the bike completely with my feet down on the ground, the motor stops appruptly with a jerk.

    The only sensor which seems to work is the gear sensor. When shiftig gears, the motor shortly interrupts as it should.

    Any idea about this?

    Thanks in advance!

    The brakes work through the main harness and to sense the brakes are on want to see a short across 2 of the wires. This means if there is a bad connection the controller will never 'see' the short and know that you are trying to brake.

    What sort of brake sensors do you have? Bafang levers? Those you can usually hear the clicks if you listen close. Hydraulic / magnetic sensors? If its those get another magnet and touch it to the sensor(s) to make sure your magnet alignment didn't get misaligned. Some magnets and some alignments it makes a difference which direction the magnet itself is oriented. Or do you have the cable type of sensors like the gear sensors? Those I think all have a light that should be lighting when they activate. If all that checks out then I would be doing a careful inspection and cleaning of the main harness connector. That is the main one with like 6 pins in it. There is a product called DeoxIT that is really good (and expensive) for cleaning small contacts.

    For the other issues I think you need to open up the gear case and see whats going on in there. You don't need to remove the motor from the bike to do this, the side you need to take off is the one behind the chain ring. You do have to remove the crank arm which after you remove the 8mm allen hex requires a puller tool like the Park CCP-22 or CWP-7. With that out of the way you remove the screws holding the chain ring on. Since you may have an issue with the crank spindle I would also take off the arm on the left side.

    That will expose several screws that hold the cover on the gear case. There are 2 pins aligning the cover so its not just gonna fall off once you remove the screws. Most of the time you can gently wack on the cover with something soft like a piece of wood or plastic tool handle and it will start to move at which point you can grab it with your fingers and wiggle it the rest of the way off. If you don't have a replacement gasket on hand you will want to look close at what the gasket is doing when it first starts to separate. If its sticking to both sides and you are going to try and re use it you may need to get something like a knife blade in there to gently detach the gasket from which ever side its least attached to. Ordering a new one before you take it apart is your best bet if you can't just leave it apart while waiting for parts to be shipped.

    There should not be any little parts or lube that will just come falling out of there. If anything does fall out you found your problem. If you leave the left arm on loose that should keep the spindle in the main housing. The cover should have a couple bearings and the big gear in it and it should all stay together if you hold it in any position. You can try turning the gear which rides on the big bearing you can see around where the chain ring bolts on.. Should be smooth. You can also use your finger in the smaller bearing in the center which is where the pedal spindle turns, that too should be smooth.

    You should see the little freewheel ratchet mechanism with its little spring loaded pawls still on the spindle. It should just slide off. If you then remove the left crank arm you should be able to pull the spindle out. There will be a ring of bearings between 2 special washers right behind the big disc that is attached to the spindle. There is also a bearing and seal deep inside the housing for the left side that doesn't easily come out.

    Those are all the parts that are involved in the pedal part. Hopefully something there will jump out as the problem. There is a special grease people say is best for these Mobil 28 or AeroShell 22. If you are just doing a quick inspection and going to order some parts and do it right later just about any lube you have laying around will likely be better than nasty old grease. The part that concerns me is how you say its not evenly dragging.

    If the bearings in the cover are suspect you should order replacements. If you can read the numbers off the seals you may be able to find replacements from a general bearing supplier instead of having to get them from Bafang. For a quick patch you can usually carefully pry the seals out which will then let you clean and lubricate them. If they are suspect there is likely damage and they just need replaced but if you need to keep using it till the parts come in that can buy you some time.

    Let us know what you find.