Broken clutch control disk.
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
Broken clutch control disk.
He guys (and girls?),
I need some help again with the clutch. In July my clutch gave up. After examening the clutch it self looked to have no problem and the slave cylinder wasn't leaking so it had to be a worn out master clutch cylinder. After a revision kit (thanks to paso750 and Nicola's tips) the hydraulics work again. However no clutch function.
Time to remove the control disk, springs and disks to see what is the problem. I soon found out. In the photo in the following link you see the clutch control disk and the press pin which should push it
http://www.box.net/shared/eycefyjafh
For you're info the control disk (part nr. 066516690 in the parts cataloque) sits on the pressure plates and holds the springs in place via 6 bolts. See picture.
http://www.box.net/shared/7l40777gp3
It looks like a part of the push pin is broken of (disk shape?). When looking at the following pics you see the brittle break area's were something was and the cavity/socket in the control disk were I think that part is falling in to.
http://www.box.net/shared/t5nzal1uff
http://www.box.net/shared/nqcp4co2gc
Because the press pin now goes through the pressure plate there is no decoupling and a small metal rim on the plate is completely pushed backwards see pic.
http://www.box.net/shared/g1q65y4x9q
Having explained the problem I'm now trying to find out how the parts looked before they were damaged. Are it two seperate parts or are they connected and which part is missing. Although I have an original workshop manual I can't get a clear picture (also not on the web). Could someone provide me with some pictures or a sketch how the part has to look, preverably with dimensions so I can rebuild, make or order new parts.
I guess this is the charme of an almost classic bike.
greetz,
Remko Spenkelink (Paso144).
I need some help again with the clutch. In July my clutch gave up. After examening the clutch it self looked to have no problem and the slave cylinder wasn't leaking so it had to be a worn out master clutch cylinder. After a revision kit (thanks to paso750 and Nicola's tips) the hydraulics work again. However no clutch function.
Time to remove the control disk, springs and disks to see what is the problem. I soon found out. In the photo in the following link you see the clutch control disk and the press pin which should push it
http://www.box.net/shared/eycefyjafh
For you're info the control disk (part nr. 066516690 in the parts cataloque) sits on the pressure plates and holds the springs in place via 6 bolts. See picture.
http://www.box.net/shared/7l40777gp3
It looks like a part of the push pin is broken of (disk shape?). When looking at the following pics you see the brittle break area's were something was and the cavity/socket in the control disk were I think that part is falling in to.
http://www.box.net/shared/t5nzal1uff
http://www.box.net/shared/nqcp4co2gc
Because the press pin now goes through the pressure plate there is no decoupling and a small metal rim on the plate is completely pushed backwards see pic.
http://www.box.net/shared/g1q65y4x9q
Having explained the problem I'm now trying to find out how the parts looked before they were damaged. Are it two seperate parts or are they connected and which part is missing. Although I have an original workshop manual I can't get a clear picture (also not on the web). Could someone provide me with some pictures or a sketch how the part has to look, preverably with dimensions so I can rebuild, make or order new parts.
I guess this is the charme of an almost classic bike.
greetz,
Remko Spenkelink (Paso144).
- paso750
- paso grand pooh-bah
- Posts: 5558
- Joined: Sun Jul 18, 2004 12:00 am
- model: 750 Paso
- year: 1987
- Location: southern Germany
Hi,
I`m trying to understand the pictures and what happened.
I`d say there`s nothing missing.
The pin belongs in the bearing/clutch piston in the clutch cover.
The part infront of it actually is the center part of the clutch control disc which broke out. Is that part and the pin welded together ?!
I`ll try to make a picture tomorrow if I find the time.
G.
I`m trying to understand the pictures and what happened.
I`d say there`s nothing missing.
The pin belongs in the bearing/clutch piston in the clutch cover.
The part infront of it actually is the center part of the clutch control disc which broke out. Is that part and the pin welded together ?!
I`ll try to make a picture tomorrow if I find the time.
G.
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
Thanks for the reaktion. Actually the part in the piston looks about the same but is still there in the cover. It indeed looks like the pin on the photo was connected to the disk by a weld.
A second inspection showed that the cavity on the disk could also be a worn out piece.
A picture of the original lay-out would be great. I don't know if it was original before I opened the clutch. Maybe the previous owner did some faulty assembly/welding.
greetz Remko
A second inspection showed that the cavity on the disk could also be a worn out piece.
A picture of the original lay-out would be great. I don't know if it was original before I opened the clutch. Maybe the previous owner did some faulty assembly/welding.
greetz Remko
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
He Jon,
I've checked the pin in the slave piston. It is turning smoothly and couldn't be the cause for the excessive wear / break down.
By the way I get the impression that you guys think the pin in the pictures is the one that goes in the slave piston. It isn't, that pin is still there. The pin in the picture is another one and was probably attached to the clutch control plate in some way.
It however has as simular shiney surface at the end as the pin in the slave piston. These surfaces form the contact between the slave piston (clutch cover) and the control disk (clutch package).
But I'm still unknown about the cause of the excessive wear/break. As I mentioned I have the feeling that I miss a piece of the control disk but I didn't see debris when opening the clutch. It has possibly completely powedered and sits as a residue (together with the worn of friction material) on the inside of the clutch cover.
Hopefully you'll have some good pictures for me. Also blue prints or other technical drawings would be great. Do you by the way have such technical info on the paso?
regards,
Remko
I've checked the pin in the slave piston. It is turning smoothly and couldn't be the cause for the excessive wear / break down.
By the way I get the impression that you guys think the pin in the pictures is the one that goes in the slave piston. It isn't, that pin is still there. The pin in the picture is another one and was probably attached to the clutch control plate in some way.
It however has as simular shiney surface at the end as the pin in the slave piston. These surfaces form the contact between the slave piston (clutch cover) and the control disk (clutch package).
But I'm still unknown about the cause of the excessive wear/break. As I mentioned I have the feeling that I miss a piece of the control disk but I didn't see debris when opening the clutch. It has possibly completely powedered and sits as a residue (together with the worn of friction material) on the inside of the clutch cover.
Hopefully you'll have some good pictures for me. Also blue prints or other technical drawings would be great. Do you by the way have such technical info on the paso?
regards,
Remko
- jcslocum
- paso grand pooh-bah
- Posts: 1714
- Joined: Mon Jul 19, 2004 12:00 am
- model: 750 Paso
- year: 1988
- Location: Eastern Shore, MD
- Contact:
Remko,
I have only the parts list drawing that you have posted in your first post.
I don't see the pin you are saying comes from the disc. I was thinking that you were referring to the pin/button in the slave.
Some more info here: http://desmodromico.com/sito2/attuatore%20integrato.htm
I don't have my clutch or a picture handy. Maybe Gerhard has one??
I have only the parts list drawing that you have posted in your first post.
I don't see the pin you are saying comes from the disc. I was thinking that you were referring to the pin/button in the slave.
Some more info here: http://desmodromico.com/sito2/attuatore%20integrato.htm
I don't have my clutch or a picture handy. Maybe Gerhard has one??
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
He Jon,
I checked my workplace manual and there the pin is visible but not a way I can work from the picture. I'll take a picture of it. The part manual I took from the site.
Maybe it's different between the old 750 paso's and the newer ones. Mine is nr. 144 from the line so it is probably produced in '86. I saw in you're mail you also own quite an old version '87. I don't know if they made changed through the 750 series or that they saved that for the 906's.
Newer Ducati's have a more common clutch approach with an hollow axle and the engagement from the other side of the motor iso the slave cylinder in the clutch cover, hence all those nice open cover which give the typical ratling sound.
greetz Remko
By the way could you give me a short description on how to paste pictures in the postings (the guideline on the site isn't very clear).
I checked my workplace manual and there the pin is visible but not a way I can work from the picture. I'll take a picture of it. The part manual I took from the site.
Maybe it's different between the old 750 paso's and the newer ones. Mine is nr. 144 from the line so it is probably produced in '86. I saw in you're mail you also own quite an old version '87. I don't know if they made changed through the 750 series or that they saved that for the 906's.
Newer Ducati's have a more common clutch approach with an hollow axle and the engagement from the other side of the motor iso the slave cylinder in the clutch cover, hence all those nice open cover which give the typical ratling sound.
greetz Remko
By the way could you give me a short description on how to paste pictures in the postings (the guideline on the site isn't very clear).
I have two clutch plates and they both have the same problem. We welded the pin to the plate on the back side of one plate, ie the motor side of the plate. It is not perfectly centered, which troubles me.
I would say welding is not a good alternative unless you can control the heat so that the pin stays "on center" while welding. Distortion while welding caused the pin to move off of center each time. Machining a larger one from something that can be chucked in a lathe then turned true was the most simple method that I could think of. In other words welding a slightly larger diameter pin to the plate, then turning the transmission side down on a lathe to the right size, thus keeping it on center relative to the plate and inside of the transmission shaft.
Maybe someone has a proven method of repair that works?
I would say welding is not a good alternative unless you can control the heat so that the pin stays "on center" while welding. Distortion while welding caused the pin to move off of center each time. Machining a larger one from something that can be chucked in a lathe then turned true was the most simple method that I could think of. In other words welding a slightly larger diameter pin to the plate, then turning the transmission side down on a lathe to the right size, thus keeping it on center relative to the plate and inside of the transmission shaft.
Maybe someone has a proven method of repair that works?
Last edited by PascoPaso on Tue Oct 16, 2007 3:10 pm, edited 1 time in total.
- ducapaso
- paso grand pooh-bah
- Posts: 1097
- Joined: Sun Aug 01, 2004 12:00 am
- model: 750 Paso
- year: 1988
- Location: siena, italy
- Contact:
It looks like your plate is broken in 2 pieces: the plate itself and the pin welded on it.
The other pin inside the bearing is very different, I'm not sure it'll be easy to replace the disc or repair it, anyway, you shouls replace the bearing and the seal before reinstalling the cover on.
The desmodromico.com page says that elder monsters had a similar piston on the wet clutch. Maybe the control plate is the same!
The other pin inside the bearing is very different, I'm not sure it'll be easy to replace the disc or repair it, anyway, you shouls replace the bearing and the seal before reinstalling the cover on.
The desmodromico.com page says that elder monsters had a similar piston on the wet clutch. Maybe the control plate is the same!
have a nice ride, Nicola
Black "DUKE" 751582
ex...Red "smooth" 753349
Black "DUKE" 751582
ex...Red "smooth" 753349
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
He guys,
Thanks for all the info. I added a picture from my own work shop manual in which you can see a clear difference between my control plate with the pin and the plate from the parts manual with only a hole (picture in Jon's reply).
Can anyone of you guys tell me what the distance between the front face of the pin and the front face of the rest of the plate must be so I can do some welding. The welding could be done by a mate of mine who is a highly skilled professional welder that welds wafestepper equipment, so he should be able to fix it needly.
For you're interest I added a photo of the inside of the clutch cover and a work in progress picture. When I still have the plates out of the clutch it's worth checking them on wear.
http://www.box.net/shared/dj44pyt3bv
http://www.box.net/shared/6o3re0b4o4
regards,
Remko
[/list]
Thanks for all the info. I added a picture from my own work shop manual in which you can see a clear difference between my control plate with the pin and the plate from the parts manual with only a hole (picture in Jon's reply).
Can anyone of you guys tell me what the distance between the front face of the pin and the front face of the rest of the plate must be so I can do some welding. The welding could be done by a mate of mine who is a highly skilled professional welder that welds wafestepper equipment, so he should be able to fix it needly.
For you're interest I added a photo of the inside of the clutch cover and a work in progress picture. When I still have the plates out of the clutch it's worth checking them on wear.
http://www.box.net/shared/dj44pyt3bv
http://www.box.net/shared/6o3re0b4o4
regards,
Remko
[/list]
Last edited by paso144 on Wed Sep 26, 2007 9:34 am, edited 3 times in total.
- jcslocum
- paso grand pooh-bah
- Posts: 1714
- Joined: Mon Jul 19, 2004 12:00 am
- model: 750 Paso
- year: 1988
- Location: Eastern Shore, MD
- Contact:
You probably want it about 1mm away from the slave cylinder button, although I don't know this for a fact!
I would block off the hole in the plate with a sheet of metal taped into place and then reassemble the clutch. Place some stiff putty on the sheet metal attached to the plate and mount the clutch cover. Then measure the thickness of the putty when you remove the cover. This will give you the total clearance and will allow you to place the welded pin at the right spot.
I don't think we have gotten to the root cause of the failure though. What caused this pin to wear thru?? If the clutch slave pin is loose and rotating in the slave (this must be checked carefully) and this pin is firmly attached to the plate. What caused the failure??
I would block off the hole in the plate with a sheet of metal taped into place and then reassemble the clutch. Place some stiff putty on the sheet metal attached to the plate and mount the clutch cover. Then measure the thickness of the putty when you remove the cover. This will give you the total clearance and will allow you to place the welded pin at the right spot.
I don't think we have gotten to the root cause of the failure though. What caused this pin to wear thru?? If the clutch slave pin is loose and rotating in the slave (this must be checked carefully) and this pin is firmly attached to the plate. What caused the failure??
- paso750
- paso grand pooh-bah
- Posts: 5558
- Joined: Sun Jul 18, 2004 12:00 am
- model: 750 Paso
- year: 1987
- Location: southern Germany
Hi,
sorry, couldn't make pictures yet. I needed to go to Italy on saturday, but had some problems with my car I had to take care of. Sunday I decided to take my Gilera for a spin and at a crossing the Audi convertible behind me decided he wanted to take off before me and knocked me from the bike, so I was busy the past days :rant:
Will only be able to take pics by end of next week.
G.
sorry, couldn't make pictures yet. I needed to go to Italy on saturday, but had some problems with my car I had to take care of. Sunday I decided to take my Gilera for a spin and at a crossing the Audi convertible behind me decided he wanted to take off before me and knocked me from the bike, so I was busy the past days :rant:
Will only be able to take pics by end of next week.
G.
- paso144
- Posts: 27
- Joined: Wed Jul 28, 2004 12:00 am
- model: 750 Paso
- year: 1986
- Location: Nijverdal, The Netherlands.
Hey Gerhard,
Hopefully no injuries accept to the bike. If you could take some pictures that would be great. When you still have the cover open could you also measure the distance between the front of the pin and the front of the control disk?
In the meanwhile I visited a ducati store nearby but no pantah enigines there. I also discussed the problem with my mate (the welder) and he recons the plate is originally also build up out of the hardened pin and the pressed formed disk part out of standard steel. There probably also joined via welding in the original situation.
regards Remko
Hopefully no injuries accept to the bike. If you could take some pictures that would be great. When you still have the cover open could you also measure the distance between the front of the pin and the front of the control disk?
In the meanwhile I visited a ducati store nearby but no pantah enigines there. I also discussed the problem with my mate (the welder) and he recons the plate is originally also build up out of the hardened pin and the pressed formed disk part out of standard steel. There probably also joined via welding in the original situation.
regards Remko
- paso750
- paso grand pooh-bah
- Posts: 5558
- Joined: Sun Jul 18, 2004 12:00 am
- model: 750 Paso
- year: 1987
- Location: southern Germany
luckily everything is ok.
So I`m back 2 days now and finally had the time to open the clutch to make some pictures:
http://www.box.net/shared/yz5173fq6m
http://www.box.net/shared/ofvsxy6v3u
the height of the pin, measured from its end to disc is 25,5mm
http://www.box.net/shared/bgh8310fvb
the height of the middle section to the disc is 3-3,5mm
http://www.box.net/shared/259bgfai5j
Hope this helps.
G.
So I`m back 2 days now and finally had the time to open the clutch to make some pictures:
http://www.box.net/shared/yz5173fq6m
http://www.box.net/shared/ofvsxy6v3u
the height of the pin, measured from its end to disc is 25,5mm
http://www.box.net/shared/bgh8310fvb
the height of the middle section to the disc is 3-3,5mm
http://www.box.net/shared/259bgfai5j
Hope this helps.
G.
Not sure where you guys have gone with this so far I've just come in on the topic. I happened to pull my clutch apart the other day to see how it works compared to the later bikes and to give it a good clean out.
On my 89 900SS the pin has been welded in from behind the plate but I can't tell if it was originally done by the factory or a subsequent repair through the years. My welds do look a bit larger than yours so maybe it's been repaired also.
It's possible that the welds failed which then allows the pin to flog back and forth a little and also spin just a little bit everytime the slave engages until the slave pin and bearing take over the turning function. Even though the slave pin and bearing is supposed to spin I would expect that the pin in the plate can spin for the briefest of moments before the load transfers back to the slave pin. Think about that plate spinning very fast, I doubt the stationary slave pin would spin up instantly. So without the weld to stop the pin in the plate it can spin ever so slightly. Do this several hundred/thousand times and it could eventually wear the plate thin enough to one day punch through. Hence the torn and flared look from the behind.
Maybe if we are looking at making a new replacement item then the front surface of that pin going through the plate could be as large a diameter as allows in the space to spread the load. Then again that one has lasted this long. But a larger diameter face might allow the pin to spot welded to the plate which would reduce the possibility of heat distortion greatly and the spot welds would be outside the wearing face.
Maybe a new plate made from high tensile aluminium then annodised gold or red would be the way to go and a 2 piece pin that is threaded and locked into place like a bolt. Then we mill some nice holes in the cover and we get as close as we can to the flashy late model clutch set ups. :lick: :laugh:
Or maybe it's time to work out how to drill out the transmission shaft without splitting the motor so we can run the later clutch altogether.
On my 89 900SS the pin has been welded in from behind the plate but I can't tell if it was originally done by the factory or a subsequent repair through the years. My welds do look a bit larger than yours so maybe it's been repaired also.
It's possible that the welds failed which then allows the pin to flog back and forth a little and also spin just a little bit everytime the slave engages until the slave pin and bearing take over the turning function. Even though the slave pin and bearing is supposed to spin I would expect that the pin in the plate can spin for the briefest of moments before the load transfers back to the slave pin. Think about that plate spinning very fast, I doubt the stationary slave pin would spin up instantly. So without the weld to stop the pin in the plate it can spin ever so slightly. Do this several hundred/thousand times and it could eventually wear the plate thin enough to one day punch through. Hence the torn and flared look from the behind.
Maybe if we are looking at making a new replacement item then the front surface of that pin going through the plate could be as large a diameter as allows in the space to spread the load. Then again that one has lasted this long. But a larger diameter face might allow the pin to spot welded to the plate which would reduce the possibility of heat distortion greatly and the spot welds would be outside the wearing face.
Maybe a new plate made from high tensile aluminium then annodised gold or red would be the way to go and a 2 piece pin that is threaded and locked into place like a bolt. Then we mill some nice holes in the cover and we get as close as we can to the flashy late model clutch set ups. :lick: :laugh:
Or maybe it's time to work out how to drill out the transmission shaft without splitting the motor so we can run the later clutch altogether.