Jackshaft questions

PsychDoc

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Sep 8, 2019
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Hopefully the pictures will provide most of the information needed. It’s going to be a tight fit. The ? Proper orientation will require elevating the plates to clear the engine base- and only give about 1/2” of adjustment. The engine is as far forward as reasonable. The yellow mark up is some of the case I believe I can trim away. The vertical orientation is a thought but I don’t know if that gives much adjustment on the chain. Couple questions-


How much adjustment does one need? Like half a links worth?


Why is there an extra hole in the plate? And how much of the plate can I safely trim?
 

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MotoMagz

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Aug 2, 2010
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I see nuts and bolts... is it bolted through seat tube? If not why not leave everything facing like it is but put js shaft behind seatpost tube?
 

FOG

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Mar 3, 2019
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How much adjustment does one need? Like half a links worth?
I'm working out the details on a jackshaft myself and I'm thinking I want a link and a half of adjustment. On a 4xx chain that'd be 3/4". But I've never built one before so what do I know?

Plan A for me is to rotate the jackshaft housing in a pair of plates I'll weld on the seat tube vs sliding it, and here's a pic of what I think will be enough adjustment.

DSCF0832[1].JPG
 

PsychDoc

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Well FOG, you seem to know that the pitch for a 4xx chain is 1/2 inch. My thought is that one full link is all the adjustment we need. Right? And, if the pitch (rollers center to center) is 1/2 inch then one link is 1 inch. And we aren’t using any fancy pants half links. And the length of adjustment is distributed over ‘two chains’- top and bottom right? So the maximum shaft movement a single link can require is 1/2 inch. Right? Or am I drunk?
 

PsychDoc

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I spent half the day staring and thinking and stretching chain for the pedal side. I wish I could say more was completed, but I believe I have a fair idea of how it will come together. And I found what appears to be a good supplier for all things chain, bearings, sprockets- I have not ordered from them yet.
https://redboarchain.com/

*edit- if it’s poor form to mention suppliers, especially the untried, let me know and I’ll avoid it in the future.
 
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indian22

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Thanks for the supplier info Doc. I've an order ready to go for Red Boar & forum monitors will let us know what's out of bounds, though other suppliers may protest as well.

Rick C.
 
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PsychDoc

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Thanks for the supplier info Doc. I've an order ready to go for Red Boar & forum monitors will let us know what's out of bounds, though other suppliers may protest as well.

Rick C.
Thanks Rick- let us know how they do.
 

MEASURE TWICE

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Jul 13, 2010
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I spent half the day staring and thinking and stretching chain for the pedal side. I wish I could say more was completed, but I believe I have a fair idea of how it will come together. And I found what appears to be a good supplier for all things chain, bearings, sprockets- I have not ordered from them yet.
https://redboarchain.com/

*edit- if it’s poor form to mention suppliers, especially the untried, let me know and I’ll avoid it in the future.
That site say all the chain they sell, be it any of the 3 grades they sell, it mentions are pre-streched or as they say pre-loaded. All the times I have bought chain I got Diamond chain. They say that too as well as many others. Not sure it you are doing this needlessly? Does it help? Anyway I have used my 35 chain on trail riding and hills and as much as I do and check for wear, I got about 2 to 3 years. 10ft for like $15 Ebay or Amazon I was buying Diamond.

I have enough chain with that 10ft to do everything over twice. I use also cogged v-belt and it does not show any problem with at least I think 5 years now. I think it is stronger than the pulley one of the two I use. The steel one the sheave no wear, but an adjustable diameter pulley got a bit of a groove in it. Still no slip.
 
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indian22

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Diamond is a trusted brand and graded. Stretched is a commonly used term in the trade, and is relative by nature of tensile strength and the tasks asked of it during testing and actual use. I use & have used various brands and grades of chain through the years on many types of devices. When set up properly and periodically maintained/serviced almost all have served well the purpose to which they were applied. I've noticed that my relatively few chain problems have been due to my errors in chain use, setup or maintenance either individually or in combination, rather than poor manufacturing or use of inferior quality materials in the process.
My opinions were formed through chain use in agricultural, mining,manufacturing, military and recreational equipment though 55 years of adult experience, not just on bicycles, motorized or not.


Rick C.
 
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