Hydraulic clutch converstion

[mrbill5491]

Mr Bill!

I need to message you! Busy as always...right?

You're sending out a "feeler" and not looking for customers...I get it.

Ed

****

Yup just a feeler and or just letting folks know there is someone out there that will work with them on a conversion if they want one. My busy part is about to slow down here in a couple weeks.

[chris]

I did a hydraulic clutch conversion on my '78 GS750. bought the slave cylinder and master cylinder from ebay and the lines from HEL Performance. Had to get a local engineer to fettle a bracket to hold the slave cylinder onto the casing but haven't missed the cable once.

Was the lever pull lighter than the cable ? The reason I ask is that I looked into doing this last year and decided that the slave cylinder would be too small in diameter to give a proper mechanical advantage. Getting a master cylinder and lever is easy, many sport bikes from the 90's came stock with them, gsxr, yzf ect. My gixer has awsome clutch feel but its slave is about 30 mm. The ones on Ebay are 10 or 12 mm, which would be fine for a 250 cc bike. I read a post on old school about a guy who did the conversion only to have the same resistance as a cable. I ended up getting a new OEM cable, it was over $70 can. Can you post pictures of the slave installation?

[erki52]

sorry to take so long to respond, too much of a technophobe to be on the forum outside of work hours. The lever pull wasn't much different to cable, I just changed it because I could. I will take a picture of the installation tonight and attempt (or my wife will attempt) to post the picture.

[Hayabuser]

And now I definitely want a cable conversion on my '85 Katana as bleeding the thing is kicking my arse after changing the mastercylinder from the temporary VFR part that came on it to the proper Suzuki unit.

This bike may never roll under its own power again at this rate....... never fix what ain't broken!

[dorkburger]

Because we are supposed to.

This is the correct answer and the reason why we still ride and enjoy tinkering wih antiquated motorbikes.

As I get older I will likely continue to adapt my 1150 to suit whatever needs arise as I slowly fall apart.

[erki52]

here's the photo of the slave cylinder. just a generic ebay item, it came complete with a lever, iffy hose pipe and the cylinder.Hydraulic clutch GS750.jpg

From memory I think i had to have the piece of bar that connects to the adjusting arm threaded so i could adjust it.

[chris]

Nice job, thanks for posting the photo.

[Rob S.]

...never fix what ain't broken!

And never break what ain't broken!

[Hayabuser]

And never break what ain't broken!

Well that's easier said than done!

[bobtail84]

I just need to send them a pic of the clutch arm/cable fitting and they do the rest.

I have been mulling this idea over for a number of years but just not got round to it, I have a Suzuki Bandit GSF1200 hydraulic clutch master cylinder (eBay) and a slave cylinder which cost £85 at a bike show a few years back from Venhil https://www.venhill.co.uk/frando-clu...ong-11nbl.html I just need to measure the size of pipe I need and spend a couple of hours fitting it all up. The slave needs 10mm thow to work with the GS. This thread might get me inspired to start or possibly not..

[bobtail84]

I just happend to be down the shed and to add to the comments on this thread I have a little info with pictures and a mock-up of the Hydraulic clutch conversion that is fully reversable and may or maynot work. I have made sure the parts fit on a mill I have on the floor in the shed which is a GS1000 again this is a mock-up and I will no doubt get around to it after I have tried the idea out on the spare engine.
I have no particular reason for doing the conversion, it's only because I can and if it works woo hoo and if not I will put the cable back on.

Parts.

https://www.ebay.co.uk/itm/1PC-Motorcycle-Adjustable-Hydraulic-Clutch-Brake-Pump-Master-Cylinder-Rod-System/174380087259?hash=item2899dcf7db:g:wcwAAOSw-2JfKmAv

1PC Motorcycle Adjustable Hydraulic Clutch Brake Pump Master Cylinder Rod System Piston diameter: 14mm
Note: the piston size of the upper pump matched with the product must be no less than 14mm, and the working stroke shall be no less than 12mm. £12.44

https://www.ebay.co.uk/itm/Clevis-Fork-End-Rod-End-Joint-M4-M5-M6-M8-M10-M12-R-H-Thread-BZP-Steel-x1/323993224599?ssPageName=STRK%3AMEBIDX%3AIT&var=513035775648&_trksid=p2057872.m2749.l2649

DIN 71752 Clevis Fork End / Rod End Joint Right-Handed Thread M5 x 0.8 Thread Pitch £2.89

https://www.ebay.co.uk/itm/SUZUKI-GSF-1200-BANDIT-1996-2000-CLUTCH-MASTER-CYLINDER/363219687284?hash=item5491949774:g:COIAAOSw53Ff1y-A

Suzuki GSF 1200 bandit 1996-2000 clutch master cylinder £24.99

You can use braided brake line and you will need to measure the length required.



The reason I went for this set up was I have read many threads on the conversion and 1 chap on another forum spent the budget of a small south american country and the difference was sod all.. I do not have the spare $$ and I if was going to convert it back due to the idea being not much better than standard I wanted to spend as liitle as possible.

The MC was from a GSF1200 Mk1 and comes with or without mirror mounts as required.



The slave cylinder has 24mm of thread and 12mm stroke. My GS1000 uses 10mm of travel your may be different.



The slave cylinder comes with a hex threaded sleeve which I threaded to 5mm so the clevis fitted.



I made sure the slave fitted using the original thread and it does.



Then mocked up to see if it fitted.






My next job will be to connect the MC, bleed the system and make sure there is enough travel to operate the clutch.

As the braided pipe can be run in the most direct route I will look to run it gown the center of the frame and down between the carbs to make the shortest and cleanest run for the pipe but that may change.

As I said at the top of my post this is just to see if it works on a reasonable budget and is fully reversable if it's a complete and utter failure which there is a good chance it will be. Both pistons are 14mm and I'm aware there is a whole lot of mathamatical voodoo in regards to displacement and force and stuff and.. well, it's complecated but I thought I would have a go.

I will update when I have more info but please let me know what you all think but please bare in mind this idea is just for fun and will probably fall on it's arse.

[Grimly]

Should work. You still have the same-ish lever advantage at the bar end and the same operating lever at the clutch end.
The hydraulic leverage is zero, exact same as the cable, but minus cable drag.

[bobtail84]

Should work. You still have the same-ish lever advantage at the bar end and the same operating lever at the clutch end.
The hydraulic leverage is zero, exact same as the cable, but minus cable drag.

To be fair I did not expect the conversion to make that much difference.

I have a luggage weighing doofa that I will try and get a base line figure for effort to move the lever before conversion then try the same after, but as you say the only true difference will be the cable drag and if the OE is set up correctly then I feel there will not be much between the two if anything at all.

[chris]

Nice work, hydraulic clutches are awesome. There is a reason why virtually all trials bikes made in the last 25 years have them. The sport is all about clutch control. If I could find a slave cylinder with a 25 mm or bigger bore I would put one on my GS, then again if I still worked at a machine shop I could simply make one. The only reason my wife does not ride my bike is because of the nasty clutch pull and yes I have a new OEM cables. I would say the clutch pull is nearly double as that of a modern bike . For a old school rider the clutch is fine it matches the heavy pull of the RS carbs.

[rphillips]

If clutch pull is near double that of the modern bike, I'd say something needs fix'in, something is wrong. No noticeable difference in my GS1100E & CB1100F cable operated & my newer Bandit, ZRX, & GSX1100G hydraulic operated. Just my opinion.