E50 Crank Choices

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E50 Crank Choices

Postby RebelRider.Mike » Sun Aug 18, 2013 4:32 am

I'm thinking of upgrading my crank assembly. Eventually, I'd like to end up with a top speed of maybe 35-40 mph, with some extra power to get up some short hills at maybe 20 mph. I hear getting a top end kit among other mods can help with that, but folks recommend a better crank.

So I guess I'm looking for a crank that can handle more power per stroke rather than extra high rpm.

I've seen them stuffed with aluminum, Teflon, or nothing.

Anyone know what makes one crank "better" than another?
Mike

1979 Puch Free Spirit
1987 Honda Rebel
2014 Ural M70
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re: E50 Crank Choices

Postby RebelRider.Mike » Tue Aug 20, 2013 2:45 am

Also, a vaguely related question:
Does anyone know the proper idle and maximum RPMs for an E50?

Thanks.
Mike

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2014 Ural M70
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re: E50 Crank Choices

Postby RebelRider.Mike » Wed Aug 21, 2013 6:58 am

I ran across a huge spreadsheet of calculations someone did relating sprocket size, RPM, and MPH. I'm still trying to wrap my brain around it, but all the calcs range from 4K - 11K RPM. This suggests to me that idle speed would be below 4K, and perhaps RPMs above 11K are not advisable. At least with stock parts.

Am I on the right track here?

I've still not found any comparison between unstuffed, aluminum, Kevlar, and Teflon stuffed crank assemblies. I'm too much of a noob to know why stuffing is even done. If I had to guess, I suppose the holes are there in the first place to reduce weight. Which are then filled with lighter materials for structural integrity, maybe?

If that's true (a big assumption on my part) then I suppose the aluminum stuffed crank would be the strongest; best able to handle extra power rather than speed. The others seem like they're designed with friction reduction and high RPM in mind.

Again, this is all a guess based on my ignorance and limited intuition. I'd love to get some feedback, or reference suggestions to some real facts. :)
Mike

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re: E50 Crank Choices

Postby supercub » Wed Oct 09, 2013 6:34 pm

I heard that the stuffing can become loose. I did put a DMP unstuffed crank in my E50 and it was doing 40mph stock otherwise, except for the derestricting and upjetting. The crank was a little larger in diameter and that may have reduced the case volume enough for some performance increase, as well as the roller bearing rod end.
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re: E50 Crank Choices

Postby RebelRider.Mike » Sun Oct 13, 2013 11:19 am

I think I'm leaning toward the unstuffed also.
I still don't know what the difference is as far as application. No one who buys them seems to know, and the sellers aren't talking either.

I may just go with whatever costs the least. I just haven't any other criteria to go by.
Mike

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re: E50 Crank Choices

Postby supercub » Fri Oct 18, 2013 8:11 pm

DMP is good and price isn't bad. The crank fit up well except The clutch shims will be different, make note of how they came out, inner and outer, and check the spec in the Puch manual for proper gaps and shim as stated.
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