Hydraulic Clutch Intrest?

angus67 said:

Hmm,,,if the clutch needs more seperation, could a new clutch rod be turned a couple thou longer?

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Angus / all: I don't think the clutch displacement is directly related to the length of the pushrod (assuming it is adjusted with minimal freeplay / end slack). The displacement comes from the clutch worm lever assembly itself. The pushrods just gets...pushed.

PS - I would be interested in a hydraulic system. May I suggest in designing it that you use standard sized seals - something that is readily available.

Cheers,

Pete

Metal said:

That's a nice looking unit. Very slim. So you know what kind of price they retail for? The site was in Dutch I think.

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The side is in German, retailprice is 300 Euro for the complete plug and play system.
From the outside, this looks like the original, no modifications needed on the engine. People i know, who use this system, are very satisfied with it.

vr3506 said:

The side is in German, retailprice is 300 Euro for the complete plug and play system.
From the outside, this looks like the original, no modifications needed on the engine. People i know, who use this system, are very satisfied with it.

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Here is a link to the installation guide in english.
http://images.xs650shop.de/pdf/51-180VA.en.pdf
And this is a link to the site for shopping. Scroll about a third of the way down the page.
http://www.xs650shop.de/front_content.php?idcat=18

Looks to be a good system, but $430 CAD is quite expensive.

looks like about 280.00 US. they seem to kist 4 different kits, which one is the correct one? That whole website is complete gibberish.

Doug79 said:

looks like about 280.00 US. they seem to kist 4 different kits, which one is the correct one? That whole website is complete gibberish.

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Any grade 3 German schoolboy, can read that website no problem at all, but every post in this thread looks like gibberish to him.
That's just how the world works. Google Translate app could be useful.

I use Chrome, not Internet Express. Rightclick-tranlate to english, bingo

Click the British flag on the top of the page for english.

I missed that! That's even easier!

That British flag made a whale of a difference. Think I'll get one of those once my build budget heals up. Had to put tires and brakes on the Road King , tires for the XS and a good size bill from the powder has a left the budget looking a bit haggard. But we'll bounce back.

vr3506 said:

http://images.xs650shop.de/51_165SW

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Vr3506: Are there reports that this hydraulic clutch setup solves the hot neutral issue? Eyeballing the slave and it appears massive. Looks like a very easy pull!

To the OP:
If your design follows Mr Riggs path, I for one would be interested. I found his thread a couple months ago, and a print-out is sitting in my projects file...
While he did a great write-up, I did not see a piston size, or what the o-ring(s) were from; unless I missed it?
In a perfect world, and assuming brake caliper parts would be apropos, using something from a still factory supported bike (for replacement parts availability) would be ideal.

pago cruiser said:

To the OP:
If your design follows Mr Riggs path, I for one would be interested. I found his thread a couple months ago, and a print-out is sitting in my projects file...
While he did a great write-up, I did not see a piston size, or what the o-ring(s) were from; unless I missed it?
In a perfect world, and assuming brake caliper parts would be apropos, using something from a still factory supported bike (for replacement parts availability) would be ideal.

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Hi Pago/all: hydraulics is sort of my thing.

From what I could gather from MrRiggs excellent post, he used a 1" bore (he stated that he turned the cast iron cylinder to 0.998" dia. and then honed it to 1.001") and then he turned a little 1/8" o-ring groove in it. Then the story seemed to stop - but I'd say that he used a piece of 1.000" dia. SS for the piston and a standard sized 1" x 0.125" o-ring - all of which make sense to me. The hydraulic pressure won't be too high and speed of the piston in the bore is low plus the motion is intermittent and the temperatures are moderate - so all of this should stand up quite well IMO.

The thing I REALLY liked was the very clever mounting arrangement using the stock clutch adjustment register in the LH side case cover and the snap ring along with flats milled on the cylinder mating with surfaces inside the case cover. Plus of course the nice "hidden" clutch hydraulic hose arrangement - which is also really nice. The bleeder screw arrangement is also a good design - even though you must remove the engine case cover to bleed air out of the system. That isn't a big deal in my view, because once the cylinder is installed and bled, it shouldn't need any attention for quite some time.

Overall, it is really nice design work and much slicker than the usual XS650 "Frankenstein" looking setup with a slave cylinder from some rice-rocket model sticking out in the breeze, just waiting to be knocked off in a low-speed drop or going through a narrow gate, and a hose dangling all over the place.

The MrRiggs design is clean, simple, efficient, robust, manufacturable, and economical. Brilliant really! I just wish he'd publish a drawing.

Pete

MaxPete - good commentary.

"...really nice design work and much slicker than the usual XS650 "Frankenstein" looking setup with a slave cylinder from some rice-rocket model sticking out in the breeze..."

So... do you think a single "common" o-ring would work? I know that on my Valkyrie rear brakes (just done this weekend) there are 2 O-rings - but they were about 3/4" diameter, and also not really "0-rings" - actually "rectangular round rings" may be a better description.

I have several bikes brake calipers laying around. Will check this weekend and see what I have that is close to the 1". Somewhere, I saw a cool chart on the mating of master cylinder with calipers. Maybe that would be useful to help mate up a CNC'd slave cylinder to a conventional 13mm or ??? master cylinder?

Is the OP still interested in running with this? I can put a drawing together if we can work out the piston details. The only other thing I could add is that my machinist guy recommended 7076 as being more than strong enough for this application; rust free as well. Ideas?

The VFR 1000 slave cylinder is 38mm and combined with a 14mm master has a light operation on the XS.

The brake pistons on an XS are 38mm and the brake seals are a square section (one only). The seals are a common size I get mine from the local car brake and clutch specialist.

The VFR1000 slave with 14mm master does not solve the hot neutral problem. Read on this forum about giving a quick rev to help find neutral, tried it and it works.

Hi Pago / All: yes, you're quite right about the o-ring. It should be a seal (sort of a flattened cross-section and harder than an o-ring) - but the principle is the same.

An appropriately sized piston from a brake caliper ( along with a matching seal) would be perfect.

The hot neutral problem seems to be related to increasing the displacement of the clutch push rod, I think to somewhere around 0.090-0.100". The nice thing about a hydraulic clutch is that you can get that longer push rod stroke without a bit increase in clutch lever pull force - if you size things correctly. There was a really good thread on that about 2 weeks ago by, I think, 2M.

Cheers,

Pete

I doubt you can get enough separation on a wet clutch to prevent oil drag not matter HOW far you push open the pack. the slight rev, release, pull, find neutral routine, squeezes the oil out from between the plates for a second, THAT is why you can then find neutral more easily.

MaxPete said:

Hi Pago / All: yes, you're quite right about the o-ring. It should be a seal (sort of a flattened cross-section and harder than an o-ring) - but the principle is the same.

An appropriately sized piston from a brake caliper ( along with a matching seal) would be perfect.

The hot neutral problem seems to be related to increasing the displacement of the clutch push rod, I think to somewhere around 0.090-0.100". The nice thing about a hydraulic clutch is that you can get that longer push rod stroke without a bit increase in clutch lever pull force - if you size things correctly. There was a really good thread on that about 2 weeks ago by, I think, 2M.

Cheers,

Pete

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O-rings should work in this application provided that the diametral clearance is kept to something like 0.004in or less. Other critical factors in the gland design, are the gland depth, which should be set such that the o-ring is in 15-20% compression, and the circumferential stretch which should be 2-5%.

Attached is a graph showing the effect of diametral clearance on fluid pressure... a suitably sized 70 or 80 durometer EPDM o-ring should work...

The reason I would tend towards using a o-ring is that it would provide design flexibility to accommodate the geometry.



Edit: that's not to say that a quad ring or square seal wouldn't be better in this application... just that o-rings "should" work.

I think a square profile O-ring seal like those used in brake calipers is best for this application. The square seal stretches slightly when the caliper piston moves in its bore. When the pressure is released, the seal returns to its relaxed shape and pulls the piston back in it's bore very slightly. In a brake caliper this provides a tiny bit of clearance so the brake pads pull away from the rotor and prevent premature wear. The same applies in a hydraulic clutch application, you don't want the pushrod in constant contact with the clutch pressure plate or it will be rotating in the bushing and seal and wear them out in short order. Round profile o-rings also tend to roll in their groove when moved axially in a bore where square cut ones resist that type of behavior. Square cut O-rings work better in a dirty environment as they tend to scrape impurities off the piston as it slides through the seal, round profile O-rings are inferior in that regard.

You beat my edit... some good points about the square seal...