I bought thie following item on Ebay last night:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 918&rd=1,1

The button is unobtanium and I will have my engineering dept take it apart and measure the button and draw it up in Autocad so that you can have it made locally.

Do we need a piston drawing too?

Hi Jon,

that`s great !
A piston drawing may be fine for guys who have access to a machine shop.
For curiosity is the "button" on the same height than the outter edge of the piston ?
I`m wondering as the edge of the piston looks a little beaten up so I would assume the "Button" and also the edge touched the clutch causing also the piston to rotate and maybe ruin the slave piston gasket.

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 lower so this risk seems smaller.

Gerhard

Wher's the o-ring?

check part catalogue TAV.10 (nr.45)
http://www.box.net/public/jzivbxrhv9

Received the piston today. The Bottun is the same height as the outer pistin. There is a coating on the outside of the piston which has chipped off arounf the outer top edge. The piston surface is perfect. Getting it all apart for drawings might be tricky.

getting the bearing out can be very tricky. I had tried, my mechanic had tried. At last we tried to drill it out and failed again. That was when we tested if there were pistons from any other Duc that fitted. Luckily that search was over after 10min

I would need to remove my clutch cover to check but is the "button" the only surface that touches the pressure plate, is that granted ?! If that isn`t so I honestly don`t understand why the piston walls are at exact the same height as the "button" (what`s the bearing for then ?)

G.

I've changed the bearing in my clutch piston recently and I've been quite surprised, watching the piston you took!
Where's the o-ring seat? I mean: my piston has a machined channel due to be a seat for the o-ring, and I can't see it in your!
The button sholud be designed in the way to push the bearing only in the inner ring (a sort of step) so to save the bearing's gasket.
To extract it you can: find an 8mm screw and sold it inside the inner ring an use it as an extractor (with a complete set of washres and spacers) or (if you have drilled and destroyed the bearing) use a "microdrill" (such as dremel multi) to grind the external ring of the bearing.
Both works requires a great tool handling and skilled workers to save the piston!!!
Have a nice work, Nicola
Dukess 751582
red Paso 753549

I'm trying to recall and see if I can help you Nicola. I was thinking the oring mounted in the cover. Mine went bad early on-maybe in the first 2 years. I think there was moisture in the factory fluid that caused corrosion in the cover. I was able to replace the piston (throw out bearing had gone bad) and hone the cover and it sealed up fine for the time since then. I'll go out and see if I can find the old piston.

The piston I have does NOT have a groove in it for an o-ring. I have not taken my clutch cover apart to see if the groove in in the housing or the piston. I looked at the parts drawing (I'll post picture later) and it does look like there should be a groove in the piston.

I really bought the part for the button and the piston was a bonus.

The mystery will be solved!

I did not find my old piston. It may still be up in the attic in a box of other parts. If I don't eventually find it, I'll have to assume I tossed it and kick myself in the rear end. Sorry.

hey guys i repaired my clutch piston you cann see my work on this site at this link with photo and description :thumbup: :thumbup: :thumbup:


http://desmodromico.com/sito/index2.htm

Piero

You have a direct link??

My Italian is very rusty!!

On the top of the page there are many title ....you have to click on OFICINA then you have to click on MOTORE and then you have to find the clutch piston repairing..... :thumbup:

Click link below:



i hope this helps
Piero