Is the primary drive shaft going to be up to the increased strain induced by adding an extension to it? Will the (bolt on?) extension be able to handle that as well?
The thought is that the extension shaft will be supported by bearing and bracket on the far end.
I think of it as being kinda like a 3rd bearing support found on KT’s
I don’t think there would be much increase in strain on the output shaft if it’s setup this way.
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Ah, that makes sense.
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I’ve been summoned?
I’ve gotta finish Bryan’s motorcase first (on spring break but should be done before may), but if I finish before I graduate I might be able to eke it out.
Due to… unpredictable circumstances at school, I’ve got a lot less time with the machines than I’d like, so things are taking a while.
I could also see if I could get a model printed at my job, we do super high precision 3D printing
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Just curious what engine you’re using and whether it can be moved to the left so you don’t have to use an extension. I know Odenthal has made a mount for the Daytona 190cc engine that Musgrave has been utilizing.
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I thought that Musgrave had a different mount to odenthal.
It’s not possible to move it inboard far enough because the drive sprocket is off set outboard from the magneto by about 2 inches. In other words with the engine against the seat, the drive sprocket is lined up between the two bearing carriers. You could claim some space back with some work on the flywheel/charging coil setup but not enough.
I have several that im testing. Yx, ZS etc. All the same CRF50 form factor.
When I talked to odenthal about the mount it sounded like it was priced as more as a premium product and not really a good fit for the goals I have for this project. At the time it seemed Iike it was still driving an non reinforced portion of the axle too.
Here’s a pic of what’s currently on the chassis. It’s already driving the axle between the bearing carriers, but it’s really not something I believe should be a practice.
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Yeah, I just had to look back at the trackmagic they setup with the 190 and it also is driving the axle between the bearing carriers. I wouldn’t think that would be a big deal other than having to make the new spot for a keyway. You could use one of these axle reinforcements righetti makes.
https://righettiridolfi.com/en/product/search/axles/reinforcement-for-axles
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I think the image of the sprocket I posted might be from Jason Lapoint’s actually. There’s something about people having to drill their axles that just makes me uncomfortable.
Thanks for that product link, didn’t realize that was thing (or maybe I’d forgotten). Problem is that by requiring a keyway to be drilled means that the package can’t deliver on the promise of being a “bolt on and bang gears” experience.
Just need a 3D printed drilling and filing fixture. I’ve had to add keyways before with a file and drill. 
Indeed, but you’re willing, capable and interested in doing that kind of work. The kind of person that this is intended for has no interest in that what so ever.
Something like this?
Not sure on depth of the sprocket, or how far the cut needs to extend to go over the shaft. It will also need some way to anchor it to the existing shaft, possibly a flat with a set screw. Overall length is also a guess.
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Yeah that one’s gonna be touch to machine. You’d need a 5 axis lathe
Is the need for a 5 axis due to the female spline?
Yeah. It’s doable on a 3 but it would be very hard.
How long is the right side?
It would probably need to be made in a couple pieces.
Thanks for looking at it, I wasnt quite prepared for such a quick response so don’t have the measurments needed just yet.
The female spline part is about 25mm if the intent is to cover the entire thing.
I wonder if we might be better off replacing the output shaft entirely, would give us the freedom to select better materials too.
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If it’s only 25mm than actually the female is doable. Male is also doable. Didn’t realize it was that short. Yeah on a second glance that’s doable. Would be two operations. Lathe, than 3 axis
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Here’s a quick pic with a rear view do the current setup.
No actual measurements yet.
Bonus: Quick running video:
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Shaft measurements needed:
Offset from where rear sprocket is now to where you want it to be.
Length of spline cuts before fillet at end
Length of shaft needed (stubby is OK)
Support:
Height from “floor” to center of the shaft
Overall size of floor and bolt hole sizes and dimensions in relation to the center-line of the shaft.
The support could be made from one piece of laser or water cut steel and bent (cheapest), or two and welded (cheap). Or made more fancy out of aluminum and bolted/welded together ($$).
I was wondering if you could get away with pulling off the timing cover (don’t really need it) and using a water jet piece of metal with a bearing pocket welded on using that cover’s bolt points along with maybe the engine mount bolt to make the 3rd bearing. It would put the bearing inside of the output gear and wouldn’t support it quite as well, but probably adequate.
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