ducatipaso.org

interesting. I didn`t know that there where different clutch mechanisms on a 906 depending on production year.

btw. I measured the pin again with a digital calliper gauge (is that the correct word for it ?) and updated the measures above.

Early 906s had slave in right side, like all 750 Pasos and later "patch" had samekind, like 907IE had in left side...

Clutch piston for sale on e-bay, (not mine)
Complete, and new. $70
Item number: 120110209202
This is the style that is in the Pantah and 750 Sport, and the 907, all have a dry clutch. I have parts from all these bikes and they all match.

Is there a different version than this one? This thread has got me a bit confuesd and thinking that there are two versions?

The versions that I have;
single O-ring on the O.D., spring on the backside, loose ball bearings for thrust, small caged needle bearing , wire retaining clip and a seal, all packed in a nice piston with a very nicely machined/ground center bit. Pack with grease before assembly. $70 is cheap for all that is in this thing.

Cheers,

ducinthebay wrote:
This is the style that is in the Pantah and 750 Sport, and the 907, all have a dry clutch.

Do You mean main cylinder in handlebar, OR slave sylinder close plates??? 907IE have totally different slave sylinder, than 750 Paso, early 906s, 750 Sport, older Pantahs....

Antti, of course ducinthebay is talking about the slave cylinder, what is all this topic about ?! :laugh:


However, ducinthebay is right. I checked the 907ie parts catalogue and it lists the piston`s partnumber: 19520021B so it`s the same as I had posted

The clutch piston of the 900SS (91-97 w/ dry clutch) (partno. 195.2.002.1B / 195.2.002.3B or 19590023B) is approx. 1-2mm...

According to the seller of the 907ie clutch piston on ebay the piston is 1.002" (25,69mm) in diameter and 0,916" (23,27mm) in height. I measured the one in my P750 clutch cover and I measure 25,94mm diameter, so about the same.
So we learn that the 907ie slave cylinder is the same as the one of the early Supersports.
The main difference to the ebay offer is that it`s $70 + shipping while I can get it from my dealer for $ 30 (at least that was the price).
Other Ducs definetely have a different size piston. We had measured some at my dealer when I was looking for a replacement, but the others didn`t match.

So let me try and understand where this is at. The Paso clutch slave cylinder parts are not available anymore. I can "maybe" use 900SS or 907IE parts if I hone the bore in the cover to match the larger diameter of the later dry clutch engines. Ad or subtract shims to length of the piston to get the same travel length as the OEM Paso. The button is impossible to remove? Has anyone drilled into the back of the piston to the depth of the bearing and button, then driven them with a drift or punch out the front of the piston? If that fails I am to make a button out of a metal that has the same characteristics thermally as well as the Rockwell hardness of the original bronze button? Silicone-bronze for reduced corrosion? The kit on Ebay did not have the bearing and button, correct?

The kit on e-bay had the button, bearings, seal, spring, o-ring and piston. The whole kit that fits into the the clutch cover.

The other version, as best I can tell, has just a smooth piston with a thrust bearing and slicon bronze insert. Does anyone have a picture of the inside of the cover? Is the seal inserted into the cover? Is the Paso clutch wet or dry? I had assumed it was the same as the Sport, but now I am beginning to wonder.

Cheers,

I could not see the bearing in the picture. I was the first bidder in the auction. Just goes to show the value of the buy it now feature. Mine is a dry clutch, but there is some question in my mind as to whether this kit would have worked in a Paso. I ordered a bearing today, but it is not the same manufacture as the one on this thread.

So let me try and understand where this is at. The Paso clutch slave cylinder parts are not available anymore.

They are available, the pin in the middle is the only thing that isn`t.
The slave cylinder is only available as a set with bearings and other parts and really expensive. The piston cannot be bought as a single part.

I can "maybe" use 900SS or 907IE parts if I hone the bore in the cover to match the larger diameter of the later dry clutch engines. Ad or subtract shims to length of the piston to get the same travel length as the OEM Paso.

you can. I`m using it and others also. Diameter is identical, no need to hone the bore of the cover, no need to ad shims. Height differs by one or two milimeters only. This piston is an alternative as you can order it as a single part.

The button is impossible to remove?

Normally the button comes out very easily, the bearing`s very hard to remove from the piston (sometimes).

The thing that confuses me a bit is that there`re pistons with and w/o groove. I guess I`ll have to remove the piston from one of my covers this evening and check. I`m sure mine is with a groove.

I do not have a DUC dealer anywhere (within 300 km) close by me, that has been my biggest problem thus far with repairing the Paso. What do you think of making a piston from pipe, low carbon-stainless- cro-moly, od 25.94mm (1 inch), id 19mm (.75 inches), bore to the depth and width of 10mm x 22mm for the bearing. Plug the bottom with 19mm x 13mm steel stock? Then put in a new bearing and button (m8 bolt of marine brass).

I just hacked the part numbers I had posted at the beginning in some meta searchengines and found:

http://www.sd-tec.de/catalog/product_in ... _id/111868

Ok, it`s in Germany but what I think is more interesting is "900SS/Monster 748/916" (btw. €30 are US $40)

http://www.ducparts.es/product_info.php ... -2001.html

here a slave piston housing is sold w/o the piston (naming partno.) but the interesting part is it says for Ducs up to 08/2001

Here fiches of the Monster 900S ie
http://www.monsoer.priewe-online.de/pic ... oFishe.pdf

and the 996
http://www.biellacorse.it/manuali/996_Eu-00.pdf

both list the mentioned number of the piston.
So the piston is probably more common used as everyone had thought.
Shouldn`t be that hard to find a Ducdealer that can check for the price and ship it.

Things just seemed clear to me now I`m confused again.
I have 3 clutch covers. 3 used and one brandnew. All look absolutely identical from the outside. The 3 used ones have no groove in the cylinder so the O-ring is on the secondary piston.
The new cover though has a groove in the cylinder and would require a piston without O-ring groove, like the one Jon bought on ebay.
I have no clue what Ducati has done here.
So my recommendation would be to pop out your clutch slave cylinder and if it`s the one with groove you can use the pistons listed, if it`s one without groove ... I have no idea ...

Here a picture of the 2 "different" clutch covers side by side (if you download the picture you have it in higher resolution):
http://www.box.net/shared/m5nam38hlv

It could be that my new cover and Jon`s piston are not from a Paso but from a Sport or early Supersport and that this may be the explanation of this difference, but that`s pure guessing.

Nice pictures!
I think you just illustrated the two different versions as best that it could be done. All of the versions that I have seen have the O-ring groove on the piston, and a smooth bored cylinder in the cover. Let's call that Version A .
The 'New' cover you have shows an O-ring groove in the cover, which would have a smooth piston, like a caliper for disc brakes. Lets call that Version B, for the brass pin in the center. The cover castings look to be identical, except for the post machining.

From an engineering point of view, the Version B would be cheaper to produce as the piston is very simple to make since it had an installed bearing, which is cheap, and the brass pin is a simple turned part. If I had to guess, it was half the cost to produce. But why would you go back to the earlier version for th 907? If I had to reproduce these parts on a lathe, I would easily choose the Version B.

I have to agree with you, I don't know what Ducati have done here. Its odd that they found two different ways to do the same job, and then drop the whole scheme a few years later. Since the Version B piston looks bigger, I wonder if they were trying to improve the clutch feel? But that argument doesn't hold as the 907 piston has the Version A that matches the Pantah, and the Sport. Maybe it was a part shortage? I wonder, do the Version B pistons fit into the later slave cylinder that mounts on the left side? Anyone have a few spare parts lying about to check it out?

I also agree that you should take your cover off and pump the piston out to check it out, if for nothing else, to clean it out. Mine was full of all kinds of ugly stuff, and the piston had some rust on it. Probably a good thing to do when you intend on bleeding the lines.

After the 907, neither of these piston types were used. The 750 engine continued with the piston in the cover, but it went to a wet clutch, and the piston has two O-rings, one for oil seal, and one for hydraulic fluid. The 900, 888/916 motors had the cylinder on the left side of the engine and is completely different.

I have an idea to get the pin out of the piston without the o-ring groove, I recomend drilling a hole in the back of the piston (outboard side) and tap the hole. Then you can use a bolt or a drift to drive the pin out. Use a set screw or low profile screw/bolt with some Loc-Tite to seal up the whole again. It makes it serviceable, and you can add grease easily.

Cheers,

After the 907, neither of these piston types were used. ... The 900, 888/916 motors had the cylinder on the left side of the engine and is completely different.

disagree. Yes , the other bikes had the cylinder on the left side, but as you see from the links posted above the "type A" piston was used also on 996, monster 900S ie etc.
I`m actually using one of those in my P750. Only difference the piston came with no O-ring but a V shaped seal which I think is even better.

I have an idea to get the pin out of the piston without the o-ring groove...

what difference is there if the piston is with or w/o groove ? Regarding the pin there`s none.

I recomend drilling a hole in the back of the piston (outboard side) and tap the hole. Then you can use a bolt or a drift to drive the pin out. Use a set screw or low profile screw/bolt with some Loc-Tite to seal up the whole again. It makes it serviceable, and you can add grease easily.

wouldn`t recommend that. If you need to remove the pin that way you`ll probably have to scrap the piston after that. The piston is moved by the hydraulic fluid and its pressure is so high that I doubt that resealing the drilled hole would withstand very long.
I never heard of an unremovable pin, but I guess I would try to open the sealed sides of the bearing to spray some WD-40 inside so it can get also to the backside of the pin. I`m sure that after some time it will become removable again.

As soon as I have enough parts I am taking it out and cleaning the whole system. Inspecting it for defects is a given. I am trying to locate an extra cover from a Sport for a "backup plan" too. If anyone wants to sell me their extra cover I am willing. The other thing is finding someone who knows how to modify these to multiple seals, or maybe even modifying it for use with the many 28mm aftermarket piston setups or whatever have you parts????