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Old 05-27-2012, 10:53 PM
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biknut biknut is offline
Motorized Bicycle Elite Member
Join Date: Sep 2010
Location: Dallas
Posts: 6,280
Default Re: My small end bearing failed

I should report what happened to this motor that broke the needle bearing. It broke another one, and I found one more damaged before it failed.

I've come to the conclusion that the rod small end is not properly machined, and that's what is causing the bearing failures.

All 3 of the supposedly different motors I bought from the Rico group had crappy crankshafts.

I've bought enough stock crankshafts now to have a basis for comparison. Now that I know what to look for I've seen a lot of variance in the quality of the machining of the rod small end. The problem is that the rod inside dia is also the bearing race for the needle rollers. If the rod isn't perfect, the needles will fail. that's what happened with this motor.

IMO our biggest challenge is getting a china girl with a good crank.
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