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two issues: BBSHD needs power to engage, and second is a bit more complicated

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    two issues: BBSHD needs power to engage, and second is a bit more complicated


    I just replaced the clutch.


    First problem:

    The BBSHD doesn't engage unless I provide 10 AMPs (or PAS 3 or greater). It sounds like something is skipping, and then it engages and then it is fine. There must be a second clutch to allow the BBSHD to freewheel when not under power.

    Second Problem:

    After 50+ minutes of riding, there is a section of road where I use high power (PAS 9). At this point, the BBSHD becomes notchy. It doesn't do it earlier in the ride, even at high power, but just this one last section. Notchy is the best word I can think to describe it. It as if a shaft isn't perfectly aligned, and it is encountering periodic rotational resistance.

    Any ideas?

    Would a new nylon gear solve either issue? The gear is on backorder.

    I am thinking of building a second ebike, so I can always have a bike available in case one goes down due to mechanical issues.


    #2
    I don't think it's a nylon gear. That 2nd clutch, probably. I've serviced the one on the gear cover, that lets the pedals not spin under power, but that one won't cause what you describe; if it fails you can't pedal, but motor still works and moves bike, even at low power.

    The 2nd issue sounds like controller cutouts due to transient low voltage at the pack. Your charge is just getting too low for the power. Maybe something is getting hot, but I'd expect that to reset a lot more slowly. Low voltage can 'toggle' power and feel choppy.
    Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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      #3
      Originally posted by JPLabs View Post
      I don't think it's a nylon gear. That 2nd clutch, probably. I've serviced the one on the gear cover, that lets the pedals not spin under power, but that one won't cause what you describe; if it fails you can't pedal, but motor still works and moves bike, even at low power.
      I did replace that clutch. No real change. The nylon gear is now in stock and I ordered it over the weekend.



      Originally posted by JPLabs View Post

      The 2nd issue sounds like controller cutouts due to transient low voltage at the pack. Your charge is just getting too low for the power. Maybe something is getting hot, but I'd expect that to reset a lot more slowly. Low voltage can 'toggle' power and feel choppy.
      I have a big pack. It is 52V*27AH. I charge to 56.6V at home, and I am usually down to 51V when I get to work. The notchy sensation is more a sense of bad rotation, than intermittent power delivery. Hard to explain. It did actually occur right at the beginning of the ride this past Friday, when I was under high power. When I kept the power between 10-15Amps, it was mostly fine for the rest of the ride home. High torque is causing issues with a bearing, and I am hoping it is the nylon bearing because that would solve both problems.

      Comment


      • JPLabs
        JPLabs commented
        Editing a comment
        OK, not low voltage then, agree.

        Good luck.

      #4
      Looks like the problem is the rotor shaft. It has a race that inserts into a bearing in the case, and that race has been destroyed, allowing the motor rotor to shift under torque. Here it is cleaned up a little and you will see it is missing the race. The rotor itself is not available from Luna, only the entire motor core. Also, the motor bearings are not available, which I will need to replace as well. One wouldn't get the case bearing if you bought the motor core from Luna, just the bearing with the core.

      Click image for larger version

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      I can't see much lithium grease. The nylon bearing looks fine...

      Click image for larger version

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      Attached Files

      Comment


        #5
        thanks for the follow up with pics!

        You can buy bearings by size, easily. They are a commodity, as much as bolts and chains are. Pick your size, order. Need ID, OD, thickness. Then decide seals. ZZ double shielded, etc.

        No seals needed inside motor, but could buy sealed and use, or remove seals with a pick.

        Or take the parts to a 'motor alternator' type shop and they will set you up.
        Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

        Comment


          #6
          I think the bearings, which all appear to be sealed, are fine. The bearing in the picture is sealed but I will replace it.

          The race must have spun inside the bearing which caused the failure. I am not sure where to get a race but perhaps at NAPA if I knew the exact size. I bought the entire rotor, which has the race, from https://california-ebike.com/shop/ba...r-replacement/

          I also picked up two motor bearings ( https://california-ebike.com/shop/ba...g-bbs02-bbshd/ )


          Comment


            #7
            Oh, OK, I misunderstood. I thought the bearing race was missing/destroyed. Do you mean a bushing, that is, a sleeve between the bearing and shaft? What part do you need?

            Just want to learn what's in there...

            Locktite on a loose bearing/shaft works pretty well, might try that.
            Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

            Comment


              #8
              Originally posted by JPLabs View Post
              Oh, OK, I misunderstood. I thought the bearing race was missing/destroyed. Do you mean a bushing, that is, a sleeve between the bearing and shaft? What part do you need?

              Just want to learn what's in there...

              Locktite on a loose bearing/shaft works pretty well, might try that.
              Yes, it is the sleeve between motor shaft and the bearing. It is not part of the bearing itself.

              Comment


                #9

                New vs Old. Looks like the race isn't replaceable.

                Comment


                  #10
                  Oh, wow, that really wore a long ways, amazed it still worked.

                  Thanks for the pic.
                  Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

                  Comment

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