Crystalyte front 408, noise issue

[jsmay311]

Hi Y'all!

I'm having an issue with a new motor that I just got, and I'm hoping someone might be able to help me out with figuring out the problem.

It's a front Crystalyte 408 motor, and when I first bolted it onto my bike, it made a peculiar noise, shown here:

[youtube]R7uEW4cvdZY[/youtube]

I think I was able to identify the root cause of the problem. The plastic cover piece (or whatever it's called) on the axle on the side where the wires come out was actually extending past the shoulder on the axle. So when I tightened the axle nut on that side, all of that axial force was being transmitted through the plastic pieces, then into the motor cover plate, and then into the bearing. And I don't believe the bearings in these motors are designed to withstand any axial loads -- only radial.



I was able to confirm this by removing the "top" plastic cover (the one with the slot for the wires to come out of) so that the axle shoulder contacted the inside of the fork directly. Voila, no more noise. But I don't think I want to go without the plastic cover permanently, so I think I might buy an extra "C" washer to put on the INSIDE of the fork in addition to the plastic cover. This should also do the trick.

But, then the question I have is: Why are these motors/parts designed like this? Why doesn't the axle shoulder protrude past the top of the plastic cover piece?

Is it possible that the axle is misaligned on this motor? I measured both sides, and they are pretty close to symmetrical (less than 1mm difference). But maybe it's supposed to be asymmetrical(???). Idk.

Any help on this would be greatly appreciated.

Thanks!
Jeff

 

[dogman dan]

Personally, I'd just chuck that plastic cover, it's what is rubbing on the aluminum motor cover when you tighten up the nut.

You nailed it, stupid design. It's quite possible though, that the axle was supposed to be pressed deeper into the stator. Then the axle shoulder would have lined up with the plastic piece better.

In any case, it's rubbing now, so chuck at least the top part of the plastic part. A c washer in there would work though.

 

[amberwolf]

I'd just add washers as needed on the inside of the plastic ring, on the axle, to just more-than-equal the thickness of the spacer, so it doesn't get pushed back against the cover or bearing.