S4RS Clutch 101

[roggie]

hello folks. I need some clarity on clutch wear and replacement.

I have a 2007 S4RS that now has about 9800 miles on it. I'm the 2nd owner, but when I purchased the bike in 2012 it only had 130 miles on the clock. So any premature wear would be due to my own bad habits. I thought I was pretty gentle on the clutch but this seems to be too early for the clutch to go. or does it?
I use the bike for commuting and weekend rides. Sometimes my commute can get bogged down with stop and go traffic.

I believe I am starting to experience some slipping (noticed during the heavy stop and go hot traffic) which I'll take the bike out again this weekend to try and confirm. I did pull the clutch apart a few days ago for a quick look and the friction pads were basically down to the metal and there are pronounced grooves worn into the clutch basket. I will also bring my digital calipers home from work and take a measurement of the plate stack. Can someone tell me what the in spec measurement is? I seem to read online anywhere from 38-40mm.

If my clutch is on its way out what replacement parts are recommended? I have ready many threads on this topic and some say Barnett are fine while others suggest sticking with OEM. I don't mind paying a bit more for OEM if it will hold up better in daily street riding. And do I just replace the plates and basket or is there reason to also change out the pressure plate and push rod?

I'll try to update the thread again later with pictures if that'll help.
thanks gang!
Matt

[Speeddog]

9800 miles is pretty early for a clutch replacement.
Generally they get horribly loud, grabby, shrieky, and unfriendly before they're worn out.

I've seen a couple cases where one friction plate loses all of the material on one side, and then the stack is so short that it'll slip.

Brand new stacks are ~38-39mm.

Minimum thickness spec on OEM plates is 2.8mm.
Clutch spring minimum free length is36.5mm.

If the throwout bearing turns smoothly, and still has a bit of drag from the seals, it's good.

No reason to change the pressure plate.

Check the pushrod for wear on the right hand end, it runs in a needle bearing in the end of the shaft.

Remove pushrod from the left side after cleaning the exposed end on the right side.
You do not want to drag any crap into the needle bearing.
If the pushrod is worn, replace it, the needle bearing, and the seal.
You may need a small pin punch to get the pushrod out of the fitting that's in the throwout bearing.

Put new o-rings on the pushrod while you've got it out.

I like the Barnett basket, as it's got the steel inserts and holds up well.

I've been universally unimpressed with Barnett plates for dry-clutch Ducatis, I've fitted several customer-provided sets.
I fitted one wet clutch pack from Barnett and will never do that again.

I've used OEM and Ferodo packs, both are good.
There are other aftermarket ones that are good.

[roggie]

thanks for the quick and detailed response Speeddog, much appreciated!

I'll pull the clutch apart again tomorrow evening or early Saturday and report back with pictures and measurements.  I do have a closed clutch cover but I am not noticing it being much louder than usual. I'll get the occasional groan, but its not too bad. Any chance the heat and stop and go traffic could have induced the slipping?

is that 2.8mm on both the friction plate and steel?

when i pulled the pressure plate off the push rod came with it. is that a bad sign?

So the OEM or Ferodo packs work with the Barnett basket?

if I am to clean the current plates and basket, is it safe to use brake cleaner? I'm guessing not on the friction plates though?

thanks again!

[roggie]

one other thing i forgot to mention is that i did install new CRG levers 2 years ago. Any chance something could have been off on the clutch lever that would have increased wear without me knowing it?

[Speeddog]

Dunno, depends how much stop n go you do, and how hard you are on the clutch.
I got 28k out of the OEM clutch on my S4, it was still above minimum thickness spec on the frictions, but the tabs and basket were so hammered that it was very loud, and had gotten grabby and shrieky.

2.8mm on the frictions.

The steels don't normally wear much at all.
The OEM steels seem to be flatter than the aftermarket steels.
I've had a couple sets of aftermarket steels make for a draggy clutch because they're not flat enough.

Normally the pushrod wants to stay in the fitting in the throwout bearing, so it wants to come with the pressure plate.

It's possible you could have done something on the lever install to set it up with no freeplay, and thus a closed system that pressurizes with heat and 'rides' the clutch.
I'll try to look at the lever setup on an S4Rs tomorrow and see.

I've done OEM and Ferodo packs with Barnett baskets.

You can use brake cleaner on the steels and the basket.
I wouldn't spray directly on the frictions, but I'll spray on a clean shop paper towel and wipe the frictions.

[roggie]

Again, thanks for the info Speeddog!

I'll report back with measurements and photos soon.

I think I've read there should be 1.5mm play in the clutch lever. Is that correct? If so I will check to see what I've got.

-Matt

[booger]

Hey Roggie where did you obtain your closed clutch cover?

[roggie]

Hey Roggie where did you obtain your closed clutch cover?

I actually bought it right after I got the bike because the stock cover had a nasty scratch down the middle. I think I got it from AMS Ducati. Look up Ducati performance carbon or full clutch cover. I think this may be the part number:

969A063AAA

Let me know if that works

[booger]

Part # is correct, AMS has it but a part search at Ducati Omaha returns no results which is surprising because it normally returns everything regardless of how old or obscure. It's a pricey cover though. Not sure what I'm going to do because I'm not super enamored with the dry clutch loudness that everyone else seems so in love with. Drowns out the exhaust.

[roggie]

yeah, I wasn't too wild about running an open clutch cover and felt this was the best looking closed cover. Pricey indeed, I forgot I paid that much!

[roggie]

Ok I pulled the clutch apart again this morning and took measurements and cleaned the pp and plate stack along with vacuuming/blowing out the clutch dust. then reassembled...

the good
- everything is within spec, albeit the low end, but still above the minimums.
- The pushrod seemed in good shape
- I also put the bike on the stand started it in 1st gear with the clutch lever pulled and no movement from the rear wheel so I think the lever position is good.
- felt no slipping on the ride

not so good
- took it out for a ride and taking off in 1st is more grabby and was groaning a bit more now. maybe everything need to resettle after being cleaned and pulled apart?

here are a few images:
springs ranged from 37.4 - 38.34


pp and pushrod cleaned up:


this is a bit concerning, the springs seem to have worn through the edge of the PP where they seat in a few areas. is this bad?



most friction plates looked like this:

and measured between 2.89 - 2.97mm


this was how most of the steels looked:


here is the stack measurement:


basket wear:



cleaned and reinstalled:

[ducpainter]

Take a scotchbrite 'cookie' on an angle grinder and deglaze the steel plates. If you have an extra curved steel, or can get one, add it to the pack in the reverse direction of the one that's in there. The curved one has the punch mark on it.

The groaning and grabbiness will be gone. The clutch won't be any quieter however.

[roggie]

Take a scotchbrite 'cookie' on an angle grinder and deglaze the steel plates. If you have an extra curved steel, or can get one, add it to the pack in the reverse direction of the one that's in there. The curved one has the punch mark on it.

The groaning and grabbiness will be gone. The clutch won't be any quieter however.

will do! thanks ducpainter!

[Howie]

I would be concerned about that pressure plate. 

[roggie]

I would be concerned about that pressure plate. 

thanks for chiming in Howie. yeah, whats going on there? there are 3 spots like that. I will admit I have a (bad?) habit of holding the clutch in at stop lights, because of the old theory its better to be in gear ready to move in case of a bad situation. But could that be causing other issues to the clutch? And I did forget to check that the throwout bearing was moving smooth. In fact how do I do that when I have everything opened up?
(never mind, i was thinking the throwout bearing was something other than that in the PP. it is fine)

Should I consider replacing the pressure plate? and if so, should I also change out the push rod seal and bearing in the pressure plate?

thanks again for all of the advice gang!