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 Post subject: Clutch woes (or, "what, already?")
PostPosted: Tue Apr 19, 2016 9:13 pm 
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paso grand pooh-bah
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Joined: Wed Jan 19, 2005 12:00 am
Posts: 676
Location: CNY, US
model: 750 Paso
year: 1988
Quick summary: my ~24k+ mile '88 750 started giving me clutch issues a couple seasons ago. Turned out the bearing in the slave piston disintegrated; while I was in there, I noticed the friction discs were exceptionally thin so I just replaced all of it. Naturally, the original part numbers for the discs were no longer available and I wound up with a replacement set - the Ducati P/N of which I'll provide later (don't have it on me).

I barely got a complete season before the replacement bearing grenaded, so I swapped that out again, no problem. Clutch looked & felt fine. I got through the rest of the season (last year), and I've barely gone 500 miles this season and I started getting clutch slip and a lot of juddering under even a slight load. Off-idle was ok, but I could very easily ask too much of it.

I pulled the clutch to check the state of affairs, and it seemed exceptionally mucky in there - and not just dust, so I'm of the opinion that the seals may have expired. However, upon inspecting the plates, they appear to have barely any friction material left. The clutch pack measures just under 33.5mm.

So I'm confused here, because I've found some indication that dry clutch Paso's should have a 33.5mm stack height, with 6 friction discs (versus 7 in my '97 Monster) bookended by 'warped' steel discs (mine aren't warped). However, I recall seeing reports of a stack height being 37-38mm. Unless, that was strictly for newer/higher out put engines?

Questions for those who'd know:
1. What's the proper clutch stack height? 33.5mm w/ 6 friction discs, or otherwise?
2. I haven't pulled the basket yet; is it just the big locknut at the bottom of the basket? What's the best practice - put the bike in 5th, hold the rear brake and crank it off?
3. How much friction material should be on the discs? Not much, I realize but - 'sheet of paper' thick, 'business card' thick, or something measurable?
4. Replacing oil seal(s). Nuisance? Figures it's brand new oil ...

Thanks in advance as always. What would I do with you lot, I dunno.

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1988 Paso 750 #753965
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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Wed Apr 20, 2016 8:38 am 
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paso grand pooh-bah
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Joined: Thu Nov 03, 2011 10:13 am
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Location: Scotland
model: 907 I.E.
year: 1994
:
fasterdammit wrote:
1. What's the proper clutch stack height? 33.5mm w/ 6 friction discs, or otherwise?

As far as I know, all the dry clutches are the same but the combination of plain and friction plates has varied over the years. The stack height should be 37-38mm

fasterdammit wrote:
2. I haven't pulled the basket yet; is it just the big locknut at the bottom of the basket? What's the best practice - put the bike in 5th, hold the rear brake and crank it off?

No way. Get yourself a clutch holding tool.
I find these very good http://www.ebay.co.uk/itm/Ducati-Clutch-look-Tool-drum-basket-748-749-851-888-916-996-998-999-SP-SPS-/321783547101?hash=item4aebcb44dd:g:9CwAAOSwpDdVfvo0
I've no experience of this one but it's cheaper and Laser tools are usually good http://www.ebay.co.uk/itm/Laser-Tools-Clutch-Hub-Drum-Tool-Ducati-5340-/161926200594?hash=item25b38dbd12:g:D1AAAOSwSHZWenYY

fasterdammit wrote:
3. How much friction material should be on the discs? Not much, I realize but - 'sheet of paper' thick, 'business card' thick, or something measurable?

Surprisingly little. The minimum thickness for the friction plates is 2.5mm. The minimum stack height is 36.5mm

fasterdammit wrote:
4. Replacing oil seal(s). Nuisance? Figures it's brand new oil ...

Not sure what you mean. Does it need replacing?

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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Wed Apr 20, 2016 11:51 am 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5000
Location: southern Germany
model: 750 Paso
year: 1987
Quote:
2. I haven't pulled the basket yet; is it just the big locknut at the bottom of the basket? What's the best practice - put the bike in 5th, hold the rear brake and crank it off?
I`ve got the same tool as Derek. Actually I`ve got three, all from Phil Thomas.
http://www.ebay.com/itm/Ducati-Clutch-T ... cw&vxp=mtr
There`s the large nut that bolts down the clutch core. If that is removed there are 8 small bolts to remove the basket.
Note that there`s a locking washer securing the nut. That`s one of those which are folded up after the nut was correctly torqued. Hence it should be replaced and not reused.


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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Wed Apr 20, 2016 6:51 pm 
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paso grand pooh-bah
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Joined: Wed Jan 19, 2005 12:00 am
Posts: 676
Location: CNY, US
model: 750 Paso
year: 1988
Derek wrote:
:
fasterdammit wrote:
4. Replacing oil seal(s). Nuisance? Figures it's brand new oil ...

Not sure what you mean. Does it need replacing?


I haven't looked under the basket itself yet, so I'm going on McTool's comment in the 3rd reply of this thread:
Mc Tool wrote:
A juddery clutch can be caused by oil contamination . If your clutch plates have sticky black stuff on them it is almost certainly leaking oil at one or both oil seals .It takes an almost imperceptable leak to cause problems . Hint :thumbup:If checking these seals, Dont blow out dust untill you have removed the clutch , then use compressed air and if the dust doesnt blow away .... its wet ... change the seals .


So I'm going on the assumption there's a seal on the clutch shaft, behind the basket, to keep the crankcase oil out of the clutch area? When I pulled the plates out, they were dusty, and gunky. I guess I'm also assuming it's oil and not ... well, I don't know what else it would be? Clutch fluid?

I'm half of a mind to let my local shop take care of it, but I'm pretty sure I've spent more time with my hands up my Paso's skirt then they have collectively, of any Paso. Nothing against them, but in the past they've called me to scrounge up my own parts, because they didn't have the resources.

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1988 Paso 750 #753965
1997 Monster 750


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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Wed Apr 20, 2016 7:55 pm 
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Joined: Mon Dec 15, 2014 11:05 am
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Location: Sleepy leafy South Birmingham UK
model: 750 Paso
year: 1987
fasterdammit wrote:
I'm half of a mind to let my local shop take care of it, but I'm pretty sure I've spent more time with my hands up my Paso's skirt then they have collectively, of any Paso.
You'll likely charge yourself a darn sight less than they'll likely charge you too.

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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Mon May 09, 2016 7:16 pm 
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paso grand pooh-bah
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Joined: Wed Jan 19, 2005 12:00 am
Posts: 676
Location: CNY, US
model: 750 Paso
year: 1988
Does anyone have a part number for that seal, or a parts diagram? I've got the recommended clutch tool on its way (thanks, G, as always!)

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1988 Paso 750 #753965
1997 Monster 750


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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Tue May 10, 2016 8:20 am 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5000
Location: southern Germany
model: 750 Paso
year: 1987
Quote:
...or a parts diagram?

https://app.box.com/s/jnbqq0149p83zybzu96sg812qbxpaa62


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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Wed May 11, 2016 6:57 pm 
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paso grand pooh-bah
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Joined: Wed Jan 19, 2005 12:00 am
Posts: 676
Location: CNY, US
model: 750 Paso
year: 1988
paso750 wrote:


You rock. :beer:

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1988 Paso 750 #753965
1997 Monster 750


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 Post subject: Re: Clutch woes (or, "what, already?")
PostPosted: Thu May 12, 2016 3:02 am 
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paso grand pooh-bah
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Joined: Wed Dec 05, 2007 12:35 am
Posts: 1502
Location: Newzealand
model: 906 Paso
year: 1990
The 2 clutch seals are a standard size available from a bearing shop , cant remember the size but the price was so good that I bought 2 sets . Size is probly written on the seal , however if ya want I can dig out my spares and get the size for you :)

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