Magura clutch

Has anyone had problems with the coating separating in the bore of the master cylinder destroying seals.

Yes, I have a bad bore, I changed seals and it didn't help, still sweats and makes a mess, I have to keep my eye on the fluid level, I carry mineral oil with me.
I have to say, the quality of the Magura stuff on my bike is bad.

Magura clutch on both the Husky and my Ktm. Oil leaks externally from the master cylinder on the TE and the Ktm slowly drinks (clutch) oil. Cleaned everything out in both bikes and can't find a cause. Carrying a Phillips head and a few mils of oil is better than the few hundred $ the new master cylinder costs. Have never had it run dry.

Maybe it is because of crappy bore material?

I am thinking some might leak in the seal for the motor end/slave side of the clutch. Oil constantly leaks from the master from the lever plunger area but the oil level has never dropped. Suggesting positive pressure from the motor into the master through the leaky seal.

The motor is vented, there should be no pressure from the motor, it all escapes out the breather.

Yes-Mine started acting up last year (2009-2012 it was fine). I have lost the anodizing in mine accept for a couple streaks of anodizing- which caused leaks. I cleaned it up with a bore brush and 1500 grit sandpaper- this improved it. But, loosing the material (anodizing) does take away from the sealing ability compared to a perfect bore with anodizing. I am loosing less fluid to none- but my clutch does become inconsistent at times- I don't loose it completely- but I loose 30-40% of the pull. This will recover on the trail. Heat seams to add to the issue but it is an intermittant issue. I can ride one day and not have an issue and another and it will return over and over.

I have now resorted to considering buying a new clutch master cylinder. Because of this, I have considered whether I should change to a Brembo, or a different Magura (the Husabergs came with Magura Hymecs) Or stick with the Magura 9.5. At this point, I haven't done anything. But believe if I want a consistent clutch at this point I need to buy new.

Mine leaks too. Have replaced master piston and seals once. If you change to a Brembo, what change is needed on the slave side? Still mineral oil or brake fluid?

The aftermarket Magura on my Yamaha WR400 works perfectly for over 10 yrs....the slaves do leak though.

The HEBO clutch I bought from Fred Hoess on my Husky 04 WR250 is flawless....makes a creaking noise from the master but always works great and has not leaked a drop. It has endured 8 seasons of racing.

The Magura on my '10 TE250 is still working good but it does not have a lot of miles on it.

Just a guess because it keeps staying full after 2.5 years of leaking without refilling.

After more research Magura importers australia told me that they had issues with the nickel coating coming away,they also suggested that because I hadn't changed the oil this has caused the problem?? The bike in question only had 700kms when it started to weep and completely failed by 900km I think it's a cop out and faulty equipment.

I honestly don't know- I don't think the slave is any different on the bikes that have Brembos. I think the hose has a different angle and could have a diferent thread. I really haven't looked into it. I was hoping to get some feedback. Brembos do use brake fluid.

The Hymec (magura) that I saw on a Husaberg used similar plumbing (hose thread/ yet not verified). I don't know if the that Hymec would be a better solution- it just looks updated and may have some benefits- exploring options is all. If you go to the magura site model 163 is what we have, model 167 is what is on the husabergs. Main difference may be the lever....
Link to magura's offroad model overview (PDF Download).
Link to Magura's site.
Pic of Hymec 167 below: (ignore slave)

The problem with these maguras isn't just the coating. The actual bores can warp. The surrounding metal is junk so the bores will ovalize over time. The lever linkage geometry and such make it hard on the bore as well and you'll usually start to see scuffing on the clamp side of the bore, nearest the lever plunger. Some peeps have tried putting ball bearings in both the plunger and lever pivot to alleviate the stress. The permanent solution is to have the master sent off and they install a hardened sleeve. Some dood was saying he went through 3 new masters in the course of two years, and it's been over 10 years since he sent it off to have the hardened sleeve installed. He said the cost was 90 bux. After that he never needed new plunger rebuilds either. Just an occasional fluid flush to keep the fluid fresh. Something to consider, as replacement, or brembo conversion will cost more.

I'd be interested in more info in the hardened sleeve approach- is there a place that specializes or is this just a special request to a machine shop that can reproduce the process?

Ultimately that's all I need is a re-bore to specs- an improved sleeve that would last to standard spec would be great!

Thanks guys for your comments.I like the idea of rebore and sleeve. I have bought an original and one has to wonder how long it will last so I will look into a refurb on the old one.
I will post cost when I know details

Where and who would be able to harden to bore?

Yesterday I bought a slave kit for the magura on my Ktm. It is a very similar unit and exchange occurs between the engine and clutch lever fluids. Evident by combustion byproducts in the master cylinder reservoir.

Both slave and master cylinders are quick to replace.

Same problem here on a '10 SMR

Considered about carfully overboring it to 10.5 and buy a KTM piston kit ... but finally got a new Husky master.
Hopefully it will be ok for a few years.

I bought my 08 510 SMR with 50 miles and it has always leaked at the master cylinder. The second time I rode it the clutch just went to the bars and the clutch wouldn't disengage. Found this out when I blipped the throttle when downshifting coming to a light and the bike almost wheelied into the car in front of me. I just keep an eye on the fluid. I top it off every 6 months. It's been this way for 3 years and still works fine.

I found this place on-line, Karp's, and will probably just send it off to have it done. They insert a stainless steel sleeve.

http://www.rkarpsleeving.com/RK_Sleeving/Home.html

I want my setup to be extremely reliable. I occasionally ride on high mountain trails where losing the clutch is "not an option"... I have also purchased an oberon performance clutch master cylinder assy.

I read somewhere that it is $90 for Karp to sleeve the magura clutch master cylinder.

jeff

p.s. I have sent Karp an e-mail to check on pricing and I will post back when I get info.