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Beginning of the end?

Discussion in 'Electric Bike Conversion Kits' started by Ruadh495, Oct 12, 2017.

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    Ruadh495

    Ruadh495 Pedelecer

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    After nearly two years and around 12,000 miles (the odo resets at about 7,000) my EBC conversion has acquired an odd noise.

    It sounds a bit like a freewheel, but appears to be coming from the front motor hub. It only occurs at speeds above the cut off. At first I thought it was mechanical (motor clutch maybe), but then I noticed the sound disappears when I stop pedaling, or set the assist level to 0. So its related to the electrics somewhere, possibly motor phasing. The display has always read 9W when power has been cut by the speed cut off, 0W when not pedaling or assist off.

    It sounds a bit like a failed motor Hall sensor, but there's no problem under load at low RPM, so not a total failure. Could be a high resistance connector somewhere, but I'm beginning to suspect the controller.

    The controller is marked K736ZWRST - LCD. Any recommendations for a replacement? Preferably sine wave, which I'm guessing the existing one isn't.
     
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    Nealh

    Nealh Pedelecer

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    Show us a pic of the controller labelling are you sure it doesn't read KT36ZWRST.
     
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    d8veh

    d8veh Pedelecer

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    The motor still spins when you're above the cut-off speed, but it's spinning with no load. I would say that something is just rattling a bit because something is worn. The most likely thing that would be affected only then is the gears and the clutch. If you have a side-plate held on with six screws, it would be worth opening it to have a look. While you have it open, it's probably worth replacing the bearings because they're very cheap from Ebay, and regrease the gears. You can buy the clutches with the gears if you need one, but we need to see which one it is because there's a few different types.
     
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    Ruadh495

    Ruadh495 Pedelecer

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    The label is pretty worn about there, so it could easily be "T" rather than "7". That means the manufacturer is Kunteng, right?
     
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    Ruadh495

    Ruadh495 Pedelecer

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    Does the motor stop rotating if assist is set to zero? That does seem a likely explanation, given the mileage. Unfortunately the motor doesn't have screws, it's the kind which requires a special tool and so far I've failed to identify the motor and discover a source for the tool. I've also discovered it's tight enough to resist typical bodges. I've been anticipating a clutch / gear failure at some point and intended to lay in a spare. Because of this I was intending to run this motor until it fails and them replace it with one which does have side cover screws.
     
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    d8veh

    d8veh Pedelecer

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    I'm not sure what happens on level zero. I would have thought that it wouldn't turn, but if you still see 9w, it might be..
     
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    Ruadh495

    Ruadh495 Pedelecer

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    0w with assist set to 0 or not turning the PAS, 9w over the cut out. So that sounds right, that the motor keeps turning without applying any power above the cut out, but is stopped when on assist 0 or not being pedaled. So the worn gears rattle. I didn't know they did that, thanks.

    I imagine the motor gears don't have long to live, which I was expecting at some point. Now I just need to work out how to open the motor...
     
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    d8veh

    d8veh Pedelecer

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    Is it definitely a problem. I've had noises come and go on many motors.
     
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    Ruadh495

    Ruadh495 Pedelecer

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    It might not be, I just don't like the noise. It does seem to be occurring under the minimum load condition (when the motor is driving just enough to keep the clutch engaged?) so it could go for some time like it. Or the grease could move and the noise disappear. I think I'll run it until it goes bang (if it's going to) and then replace the motor with one I can get into. 12,000 miles without maintenance (can't get inside to grease it) isn't bad.

    An upcoming job change means I won't have the 25 mile daily commute anymore, so could be going back to an unassisted bike soon anyway.
     
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    raymee

    raymee Just Joined

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    7000 miles - that cant be bad, a great advert and testimony please Call EBC on Monday they will send you a new one FOC
     
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    Ruadh495

    Ruadh495 Pedelecer

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    11,000 miles, more or less. I've got the odo set in miles, though I suspect the reset at about 7000 was when it reached 10,000Km. It's done 25 miles a day, 5 days a week for almost two years. Only thing that's been done to the kit has been charging, though the bike it's fitted to has needed a bit more. Needless to say I am rather impressed with the kit.
     

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