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Feel motor shift when applying throttle

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    Feel motor shift when applying throttle

    When I apply some throttle to my BBSHD, I feel a noticeable shift in the motor when first applied. There is no shift in the cranks when pedalling. Wondering whether I need to take the motor apart?

    #2
    Are you sure its not the rear wheel.

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      #3
      Is the motor moving? It must rest against a frame member to absorb the torque, otherwise it will move.
      Alan B

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        #4
        I'm not sure what you mean by 'feel a shift'. Could you be describing the motor clutch engaging? If not pedaling, you will get a clunk when you hit throttle. Once per throttle application. That's the clutch engaging, and is normal.
        Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

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          #5
          I have this clunk or knock, but I can feel if I put hand on motor core housing you feel it a lot.
          bit worried there might be something broken or bent ,it's only on pull off.

          Any help would be great thanks

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            #6
            Originally posted by Bowers1988 View Post
            I have this clunk or knock, but I can feel if I put hand on motor core housing you feel it a lot.
            bit worried there might be something broken or bent ,it's only on pull off.

            Any help would be great thanks
            I'm guessing you've eliminated the motor being loose in its mounting position?...no slop in the bottom bracket interface with the motor? If the motor is tight, I notice two things in my BBSHD/mountain bike application. You can detect the clutch engaging but it's very subtle. The second and more noticeable "clunk" in my case is the XT rear hub. The number of engagement pawls affects the feel and how quickly the rear wheel starts turning when you pedal. Some hubs have a very high number of engagement points in the hub and some don't. My XT hub has a fairly low number and one can feel the "slack" or space being taken up before engagement. You can test any hub by holding the rear wheel and crank arm. Take up the engagement slack with the crank arm going forward. Now move the wheel forward a few degrees. Hold the rear wheel. Now turn the crank arm forward, and you will see and feel how much engagement slack is present in that hub. Some are miniscule and some are sloppy. My XT is sloppy, but I know what that "clunk" is and am not that worried about it. It's a strong hub, but when it dies I'll move to a different hub.

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              #7
              Yea I get what you saying but to rule this out I put weight on pedal etc and all so when moving bike backwards very slow you get the same clunk type noise and feel.
              think nylon gear is on its way out.

              I have a hope pro 4 rear hub and it's only 4 pawl engagement.
              But if it was this it would of done it a long time ago. Bike has been built for like about a year something like that.

              Have check lock nut etc , this was the first thing I thought it might be .

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