theTRUTH

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walkingpace
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Location: Central Coast NSW

Re: theTRUTH

Post by walkingpace » Tue Aug 08, 2017 4:32 pm

The other issue might be available bearing sizes. I can't find any with an ID that will fit that size shaft so it may need to step down a little either side of the spline. with two bearings between the sprocket on the left and the clutch unit, and then another two on the far right side as close as possible to the final drive sprocket, bending forces should be reduced to almost nothing, with the shaft itself only dealing with torque. It makes sense in my head anyway...

When you think about a gearbox, and the length of the internal shafts combined with the side load from the gears, I think it will be fine.

I'm going to do a proper drawing so I can start getting some quotes for it. I'll post it on my build thread once it's done. I can measure the thickness of my clutch unit tonight too although mine is an older model and may vary a little with the pressed steel pressure plate.

russelllowe
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Re: theTRUTH

Post by russelllowe » Wed Aug 09, 2017 10:31 am

Yes, I was wondering whether it was ok to run a bearing straight on a spline or if there should be a sleeve that's smooth on the outside and splined to the shaft on the inside; my reasoning is it would be better to go bigger re the bearings (and shaft) than smaller ... but that's just seat of the pants stuff.

One shaft should make adjusting the primary chain tension easier too.

The way I was thinking there is only places for three bearings (with the distance between the drive side bearings being the length I was concerned about earlier; between bearings labeled 1 and 6 below) ... be interesting to see your version; quick sketch below ...

Image

Looking at it now, I imagine the step up to lock the bearings on the drive side in place could be a sleeve (or circlips I guess) and it would be good to have a larger sprocket carrier for the output sprocket ... I'd like to go quite large on the sprockets to give the chain an easier time (38 teeth rather than the normal 17-19 teeth that you usually find on motorcycle drive sprockets).

Cheers!

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walkingpace
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Location: Central Coast NSW

Re: theTRUTH

Post by walkingpace » Wed Aug 09, 2017 4:49 pm

In the CB750 gearboxes I'm sure a couple of the bearings ran on splined shafts but I'm stretching the memory a bit. There was definitely a couple of sleeves in there as well so who knows.....

It seems facebook have changed the way they operate and the linking of pictures is no longer working for me. Fortunately what you proposed in your picture is pretty much exactly where I was heading :D

I've also had an idea for running the clutch hanging out the left side like a Harley clutch with the splined shaft poking through the centre of the flywheel from the back. It would allow a little simpler design and remove quite a bit of rotating weight. The downside is it increases frontal area a little bit, especially after you add the throwout bearing.

russelllowe
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Re: theTRUTH

Post by russelllowe » Wed Aug 09, 2017 9:52 pm

Yeah, photobucket (or whatever that's called) has changed it's policy recently too ... leaving tons of broken pictures all over forums everywhere.

Good we're on the same wavelength though.

Funny thing is I was thinking that because they (the Quarter Master clutches) are so small, they could go back onto the end of the crankshaft ... but, if I get what you are saying... it could be outboard a bit so the chain run was inside, near the motor (making the need for the structure out at the end less robust/large ... more like the outer bearing support that some old 4 speed Harley's had).

In other words; what would have been the gearbox input shaft (connected to the clutch friction disks) is fixed solidly to the end of the crank and the primary sprocket is fixed to the back of the flywheel button (what they call it when there is no starter motor ring gear attached). Essentially it's just the opposite of how the clutch was intended to be used ... but I'm pretty sure "force" doesn't care about that!

I would think that moving the sprocket inboard of the clutch reduces the stress considerably.

The throwout bearing is still out there, but I think I'l need to run the lower pulley/harmonic balancer on the opposite end anyway. Symmetry loves company.

Not sure where it saves rotating mass, but it does simplify the shit out of the jackshaft.

I feel another drawing coming on!

Cheers

russelllowe
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Re: theTRUTH

Post by russelllowe » Wed Aug 09, 2017 11:53 pm

And here it is ... could be onto something with this one:

Image

The outrigger support structure would need to be less that the the diameter of the clutch and the contribution to frontal area is 7.25" times the width of the setup ... so not much; and as before, could be symmetrical with the other end anyway.

(7.25" I think is the friction plate diameter, so with the housing it'll be a bit bigger, but you get the point).

The splined shaft is short enough to use a cut down input shaft from a Tremec gearbox, or similar, with a welded flange on the end. Actually, it could even float in the pilot bearing at the crank end (the flange that bolted to the crank could have a splined hole in its center); meaning it's just an input shaft with the gear cut off.

In some ways it's like the E.J. Potter setup but with an inboard sprocket. Have you ever noticed how he could put his foot down between the primary drive and the frame of his bikes?

Cheers

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walkingpace
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Re: theTRUTH

Post by walkingpace » Thu Aug 10, 2017 3:12 pm

That isn't quite what I mean although it isn't a bad idea. I was actually thinking more along the lines of the way a standard Harley clutch is arranged. The whole thing is mounted on a jackshaft behind the motor with a chain driving a collar that the flywheel is bolted to. The clutch then protrudes out the left with the throwout bearing on the end. The driveshaft however pokes back through the other side (to the right of the unit) where it picks up the final drive sprocket.

I've drawn a basic diagram but I no longer have any capacity to post pictures. If you are interested to see it PM me your email and I'll send it to you directly. It also happens that the shaft I have out of an old aussie 3 speed gearbox is nearly the perfect size (1.160" diameter) to make it so I'm going to give it a bash. It saves rotating weight over the first design due to the much shorter shaft as well as significantly smaller sleeve.

russelllowe
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Re: theTRUTH

Post by russelllowe » Fri Aug 18, 2017 10:49 am

Wohoo! It's arrived (after two visits to FedEX and a smash in the nuts from the tax man) ... looks really nicely made ... some approximate dimensions:

Overall diameter: 215mm
Overall depth (with the hydralic release bearing on the front): 125mm

Surprisingly small.

Image

Below is Nick's drawing he mentioned above:

Image

On reflection I think it makes more sense to put the clutch back on the jack shaft (rather than on the end of the crank) as either way I'll need a jack shaft anyway. And given the whole setup is so narrow I recon I might get away with a bearing at each end of the shaft ... so my setup will look similar to Nick's but supported at each end instead of the middle and the clutch basket reversed so it stays out of the wind. Ok, so maybe not that similar! I will take Nick's lead and compress my sprocket carrier design so that it uses only one bearing though.

Another drawing to come... hopefully with enough dimensions so I can price it up.

Cheers all!

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walkingpace
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Location: Central Coast NSW

Re: theTRUTH

Post by walkingpace » Fri Aug 18, 2017 1:55 pm

Looks good! I just bought the steel I need to make mine from Edcon in Brookvale. They do 1045 medium carbon which is capable of being hardened but it sold unhardened. They do round bar in some BIG diameters too which I haven't seen anywhere else and the price is not much more than mild steel. They will also sell you really short offcuts and not require you to shell out for a whole length.

russelllowe
Posts: 92
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Re: theTRUTH

Post by russelllowe » Sun Aug 20, 2017 4:50 pm

Hi Nick, yeah really happy with it. In some ways it didn't need to be small or light weight ... but it's nice that it is; feels like it will put less stress on the system.

Version 5 seems like it might be the one ...

Image

It's 165mm from input sprocket (from the end of the crank) to the output sprocket (to the left side of the rear wheel). That gives me about 40mm to make a bracket to hold the hydraulic clutch release bearing in place. I figure I might need about 6mm to do that (I'll wrap the bracket around the outside of the unit to give it some depth/strength).

On the drawing, the numbers are:

1. custom made pillow block (probably 65x25 solid bar with a hole in the middle for the bearing) so I have a flat surface to use some bolts against for adjustment ... like a regular rear axle adjuster; and so it takes the for/aft load off the hold down bolts.

2. input sprocket and carrier (bearing pressed into this).

3. clutch itself.

4. hydraulic release bearing unit.

5. output sprocket on a repurposed clutch plate center (that has the 1 5/32" spline already cut into it).

The 1 5/32" spline runs through the center of the shaft with the two ends turned down enough to let the clutch plates slip on and to an appropriate bearing size. I'm thinking spherical roller bearings would be helpful so if they might accommodate any (small) misalignment from end to end.

Does anyone have a worn out clutch friction disk with a 1 5/32" 26 tooth spline that I could rob the center out of? I have the new one that came with the motor, but it seems like a waste to cut it up ...

Also, does anyone have a bearing supplier that they could recommend?

All advice or opinions on the latest version very welcome.

Cheers!

russelllowe
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Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Sun Aug 20, 2017 5:02 pm

Actually, I think side mounting the end bearings is the way to go, and these look good:

Image

Anyone know where you can get these in Australia?

Cheers

russelllowe
Posts: 92
Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Mon Aug 21, 2017 10:22 am

Grabbed some bearings and pillow blocks on the way into work this morning (from Hooper Bearings in Alexandria, Sydney). Thought a bearing in the hand is worth two in the bush; they aren't as nice as the ones in the last post, but I can keep going which is good.

Image

25mm inside bore, self aligning, rated to 12,000rpm, made in Japan.

In my excitement I forgot to ask about the bearing for the clutch itself ... I guess that's what tomorrow morning is for. I'll take the clutch along with me which should help.

Cheers

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BONES
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Location: Killara Sydney

Re: theTRUTH

Post by BONES » Tue Aug 22, 2017 6:32 am

Hey Russell
See if Hooper have bearings with a tapered sleeve to lock them onto the shaft. They may not be available in the size you need
I think it would be better than using grub screws and putting stress risers in the shaft.
Try to use metric bearings where ever you can. They will be cheaper and more available.

cheers Bones

russelllowe
Posts: 92
Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Tue Aug 22, 2017 12:45 pm

Hey Bones,

Yeah, sizes are pretty limited. I wonder if I need to lock them onto the shaft at all? Wheel bearings aren't locked onto their axle ... am I missing something?

Definitely using metric bearings.

Picked up two more Nachi bearings this morning for the clutch itself (25mm inside bore, 47mm outside diameter and about 15mm wide). I'll run two side by side to help counter any rocking that might take place during clutch take up. I'll have to make a sleeve between the outside of the bearings and the inside diameter of the flywheel button, which is 2 1/16". It gives me about 2-3mm of wall thickness in the sleeve which will also have a lip around the outside and maybe a cir-clip on the inside ... but I'm not sure that would be necessary if it was pressed in.

The guy at Hooper Bearings thought the sleve/shoulder should have a cir-clip and that it should be made of something pretty tough (like 4140). Any opinions out there?

I also visited a local engineer this morning, Nix Engineering, and while he was very nice about it and had some helpful suggestions he said he wasn't set up to do spline cutting. Hooper's then suggested Gear Makers in Caringbah. I've just got off the phone with Peter there and he says he can sort me out, so I'll swing by with all my parts next week (work is getting in the way this week!). I'm very happy to find someone. Was getting nervous that anyone with the gear to do it might not be interested in such a small job. I shouldn't count my chickens, but it's a start.

Cheers!

russelllowe
Posts: 92
Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Tue Aug 22, 2017 12:50 pm

Bones, I just realized that's the first time you've not mentioned using a Hayabusa motor ...

You'll be putting a diesel truck engine into your bike next.

Welcome to the dark side!

Cheers!

bobthebike
Posts: 16
Joined: Fri Jun 16, 2006 10:09 pm
Location: NSW

Re: theTRUTH

Post by bobthebike » Tue Aug 22, 2017 5:53 pm

Hey Bones,
That's a great idea of Russell's. Magirus Deutz Diesel,V8, pre 1987, air cooled, you will just need to fit carburettors and spark plugs and you will be able to run A-CG or F:-))))))))
Bob.

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