Ducati Monster Forum

It's been a while since I looked for a replacement clutch slave cylinder for my 2000 M900.  What are the best options these days?  I value function over beauty.

I currently have an Evoluzione slave cylinder and have never been really satisfied.  I never objected to the strong pull required of the stock unit; I got the Evoluzione because the stocker was disintegrating.  The replacement is easier to pull, but doesn't push the pushrod as much - maybe 2mm - and I have to fiddle with the plates and springs to find the sweet spot where it works well.  And that's where I'm at right now, fiddling with it and wondering if a better slave cylinder is out there.

Thanks.

Still rocking the stocker on my monster, but quite happy with the yoyodyne unit on the SBK.  Very functional and well-built not bling.  Not up to date with their current offerings, but if I needed one today I might look there first.

BK

I just replaced a stocker on my 01 M900 which was leaking with the upgraded stocker. The new unit has the pushrod with the anti turn pin. I find it a good setup.

Do you know what the bore is on your Evoluzione?  If memory serves me correctly there were some 30 mm bore replacements available that were a bit too much.  28 seems to be a better number (if you want to reduce effort over stock).  If so, here is a good one  https://monsterparts.com/products/oberon-clutch-slave-cylinder   

Not sure what the bore is in the Evoluzione slave I have.  I'll consider the Oberon, and I see PSR models available online, but I have a couple more questions...

Would an upgraded stock unit be available only from the dealer?

Is it possible or sensible to rebuild the original?  I still have it.

Thanks, guys!

I think Evoluzione sold two bores, 28mm and 30.  I could be wrong.  Oberon is 28mm, don't know about PSR.  Wider the bore, less effort, trade off being less travel. 

I don't remember, but I think 2001 was first year of no longer rebuildable  slaves, but there is an easy way to tell if yours is.  The non rebuildable units have a large hex  on the front, like for an allen key. 

more like a triple square/XZN but yeah

I was thinking that too! Lol!

Yes it does.

They'd be rebuildable if they weren't chemically welded into 1 piece.

There's a good thread on this worth searching for.
Iirc old oem 26, new oem 28, Oberon 29, Yoyodyne 29.

I had an Oberon fail within six months so went back to stock on my Hyper. Running the old oem 26mm version on my M900. Works beautifully and I hear some dealers have rebuild kits for them.

I didn't find that thread, but I called my local dealer who told me that the original part for my bike was in fact replaced by another, part number 23610104A, which is just the clutch slave housing.  I poked around online and see that there is also a rebuild kit that goes along with it - you'd need both.  There are photos at the following links.

part # 23610104A
Ducati Clutch Slave Cylinder for all Ducatis 2000 and earlier.   This is the outer housing only.
https://www.gothamcycles.com/Clutch/Ducati-Clutch-Slave-Cylinder-Early-Style_1.html

part # 19590023B
OEM Ducati Clutch Slave Cylinder Spring & Rebuild Kit for all Ducatis 2000 and earlier.
https://www.gothamcycles.com/ducati-clutch-slave-cylinder-piston--spring-rebuild-kit.html

I don't know what the diameter of the bore is, but I'm leaning towards this.

Oberon would be my vote. A Yoyodyne came with my bike and I am not crazy about it. Not sure if an Oberon would be better but my mechanic swears by them. Someday when I have extra funds I'll make the switch for the hell of it.

Iirc, ducpainter has used the rebuild kit. I think the seal kit and a hone.

I still have the original slave on my bike. There has always been a seal available for that cylinder. It didn't come with a piston. I'm not aware of a kit that includes a piston and spring...or a boot. Mines been rebuilt more times than I can remember. I only use the clutch for starting off and lightly on downshifts.

A new cylinder shouldn't need to be honed, unless the bore is simply drilled, or bored on a mill.

ducpainter, do you think these two are all I need?
piston and spring kit: https://www.gothamcycles.com/ducati-clutch-slave-cylinder-piston--spring-rebuild-kit.html
piston spring oil seal ring gasket: https://www.gothamcycles.com/Clutch/ducati-clutch-slave-cylinder-piston-spring-oil-seal-ring-gasket.html

and optionally the housing.  Have you replaced just the oil seal on yours?

I'll try to remove the piston and seals from the old stock unit and see how it all looks.

I've never replaced the piston or spring on mine...just a seal, and used a hone to clean up/deglaze the bore.

Buy a 930.4.009.1a seal, a 93785.0822 seal, and if yours is leaking a 672.1.006.1a boot because brake fluid eats the boot, and the boot keeps chain mung off the outer dust seal and out of the cylinder.

Those 3 items will set you back about $11...ish. $70 for the piston kit is ludicrous.

When you get the parts check back in and we'll discuss the rebuild procedure. You'll need a hone of an appropriate size.

Great info, ducpainter, thanks! I think I'll give it a try.

For the curious, here's a page that shows the three parts mentioned and prices.
https://www.ducatimcparts.com/showassembly.aspx?ukey_assembly=439905&ukey_make=1051

Makes me want to stay with the old style 26mm oem on the old M900. Works well.

ducpainter, do you have any suggestions for removing the seal ring (93785.0822) from the piston? Mine's a bit crudded up from having been removed and put away without disassembly and I haven't figured out how to pull it out yet without damaging the cylinder.

I got the cylinder out of the housing by using a small electric air pump.

Clean up the crud with some fresh brake fluid and some fine scotchbrite. You should be able to use a pick to slip the old seal off the piston once things are cleaned up a little.

Follow up:

I got the seals, smoothed out the bore of the original slave cylinder as best I could, and re-installed.  Have only had a short ride since then, but the slave does not appear to be leaking and the clutch is again working as it should.

There is what I believe is a pre-existing leak from where the pushrod passes through the engine case.  Might have to do something about that.  Could be a coincidence, but it started after a recent service that involved a switch to full synthetic oil.

I measured the bore of the Evoluzione slave and it's 28mm.  Stock is 26mm.

I've got a 2,500 mile road trip coming up in a few weeks, so will get in some more miles soon to see if it'll do the job or if I'll have to break down and get another unit.  Hoping to keep the stocker. 

Fingers crossed.   

 [thumbsup]

Oil getting past that pushrod means it is time to replace the two little o rings in it's grooves (on the slave cylinder end).
Do a search on this type of leak for more info as there is alot posted on this topic. Sponsor California Cycleworks stock these little o rings.

Those rebuild kits are $47.00 from Ducati Omaha for future reference

How much is a new oem clutch slave cylinder?

I think you'd have to order the parts individually.  When I talked to my local Ducati shop I think the housing was 110 CAD, so roughly 85 USD.  The seals, as ducpainter pointed out, are something like $11.  Don't see why you couldn't re-use the cylinder and spring.  And you should probably replace the copper crush washers around the banjo bolt - another buck or so!

In my case, the housing needed a fair bit of work to get it nice and smooth.  Hopefully smooth enough.

I've replaced the O-rings on the pushrod already, so I'll clean it up, do a little more riding, and check again.

Usually the worst part of the cylinder bore is at the outside edge and is caused by moisture from the outside. The seal never gets out that far, so that doesn't have to be perfect. If you hone enough to remove that every time you'll get the bore too large eventually

2,700 miles later and the stock slave cylinder is holding up just fine with the new seals.  One tip that my local dealer gave me was to use Scotch Brite on the inside of the slave cylinder bore and to focus on removing any grooves or scratches that are in line with motion of the piston.  I definitely recommend going this route versus getting an aftermarket unit unless you really want a lighter pull at the lever.

 [thumbsup]