1198 Clutch Understanding

Hi fellas,

I have taken a look at my OEM (non slipper) clutch while fitting an EVR pressure plate & have some questions if I may (I'm not having any problems with it; touch wood).

Stack Height
Is this measurement a total of all steel plates & friction plates combined? Yes

What should the stack height be for a 2009 1198s? Dunno

I cannot see it in the manual but searches indicated 38.5mm +/- 2mm. Mine measures 42mm. It is the original , having covered 11k miles. I have the correct number of plates, in the correct order (as per the manual). I wouldn't worry too much if it's been working fine & doesn't extend too close to the end of the drum

Should this measurement increase or decrease with wear? Decrease

Clutch Springs
The online version of the manual >> http://a20.net/~bert/files/ducati/1198-manual-2009/wsm/en/home.html << indicates they should not be less than 41mm, but the downloaded version states 36.5mm (Image attached).

Which is correct? Dunno, not hyper critical but too short and the clutch will slip, too long and they'll bind and you could snap a post if overtightened

Pin
I have attached an image; a clutch parts overview. Number 19 (Pin); what is this for? My clutch doesn't have this part. Probably does but you can't see it, the pin sits between the top hat spacer (under the drum nut) and the drum, I think its to prevent the top hat from spinning

Tang Gap
The manual says I should be aiming for a gap not exceeding 0.6mm; mine are approx 1.1mm. Should this be getting attention sooner rather than later (new friction plates & basket), or is this not so important? I've ran mine with gaps that size & slightly bigger no problem as long as the tangs & hub aren't battered and notchy, overall yours doesn't sound too bad at all if there's plenty of friction material left and tangs/drum & hub aren't badly worn I'd clean her up and put her back together. Check carefully the EVR plate is the same dimensionally as the stock one ( spring pocket depth, their position relative to friction face and it's correct positioning relative to the drum )

I know it probably makes for a noisy rattle; I may try the quite mod whilst I'm at it. I like it rattly

Any input is much appreciated.

 

It's a measurement across all plates. Stack height is far more relevant when using a slipper clutch. For the stock clutch, there is a wear limit on the friction plate thickness. Pack thickness will decrease as wear takes place. If it's working fine, then no worries. When the wear limit on the friction plates is reached then it's time to swap out.
Many of the manuals online are of a "draft" copy that got leaked. They're riddled with errors. Again, unless you're getting problems, I wouldn't worry. My manuals give free length at 41mm minimum.
The pin is for locating part no. 20 to prevent it spinning. If it's missing or been damaged, it's worth getting sorted as if the spacer (20) spins, so does the lock nut.
Tang gap is what makes the clutch rattle. The bigger the gap the louder it gets. The factory wear limit is tight and if you replaced once it was reached, you'd be getting thru a lot of clutches. I've seen clutches with close on 5mm of gap! They're noisy and take up is a bit grabby but still work, ie don't slip. If you can live with the noise and it's working then it's fine. The bigger the gap though, the more accelerated the wear on the plates and basket becomes. Use a bit of common sense when to change out is my advice.

 

As Nelly says, the wear accelerates with wear but if you do carry out the quiet clutch mod, the wear becomes unimportant because the stack no longer oscillates. As you release the clutch lever, the tangs move against the driving side of the basket slots and stay there. It doesn't matter if there is a large gap behind them because they remain in contact with the drum. In fact, it actually helps to have more clearance with a notched drum because if you put new plates in a badly notched drum, you will get horrendous drag because the new sharp-edged, full-size tangs will catch in the notches, stopping the clutch from clearing properly. I did exactly that and the drag made the bike almost unrideable. I cured it by putting some old plates back in at the top of the stack and it's been perfect ever since.
On the way though, I tried reducing the stack height to stop the drag. It didn't. However, what it did do was give a really light lever action - two-finger light. This is due to reduced pre-load on the clutch springs
Theoretically, this should make the clutch more prone to slipping but I've left it like that and get no slip at all.
So I then ended up with a clutch with a fairly badly notched basket, new friction plates in the bottom half or two thirds and old ones in the top half or two thirds and a much reduced stack height.
It works perfectly. I get no drag and no slip whatsoever and the lever is still 2-finger light. Not only that but I no longer hear the clutch trying to bash itself to bits and it probably never will. Derek on here has been running the quiet clutch mod for some years and got 36000 miles out of a set of friction plates before they wore out. When he dismantled the clutch, he found that wear to tangs and basket was negligible.

Btw, the other side to the coin of a low stack height giving reduced pre-load, so a lighter lever is that a high stack-height will give increased pre-load, so a heavier lever.

 

The first advocates of the quiet clutch mod reckoned to put two old friction plates in first but most people found that two wouldn't fit, so put in just the one.
A mate of mine didn't bother with that and simply re-ordered his existing plates and it works beautifully. I started off with an extra plate but when I was trying to reduce the stack height in an attempt to solve the clutch drag issue, I wound up with the normal number of friction plates but with the first one at the bottom and alternate plain and friction with a plain at the top - no doubled-up plain plates.

Your clutch sounds remarkably rattle-free on that video. when you removed the first plain plate, did that leave you with a friction plate at the bottom?? If so, that's the quiet clutch mod.

 

Sounds perfectly normal.