Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > The Difinitive clutch answer please?

[Bryan996]

I have spent most of this morning going over old threads in both message boards looking to get my head around the situation of clutch packs. The reason is that my 996sps is very rough pulling away, yesterday i sat on a 998bp for the first time and pulling away on it was no differant to a honda and very smooth.

I placed a post recently about the clutch slipping and gripping on take off and after removing the dished plates solved the problem. I am by the way running an aftermarket slipper clutch.

So my question to all you clever people is:
1) the friction plates look to have coppper based friction material. Are these god bad or normal, race or road plates.

2) the 998 runs 9 friction plates, the 996 8 friction plates, what is stopping me run a 998 clutch pack ( in the slipper clutch) and why the differance (engine output is about the same sps to 998bp).

and finally 3) a lot of people use ST4s alloy plates. are these a good idea, how many friction plates are used and what is the friction material/will it be smooth. Anyone using them in a slipper clutch.

I belive that there must be a definitve arrangement that will work for road use in most bikes as all dukes have the same crank cases. In one thread someone sugests cleaning the friction plates with wd40, surely thats like putting oil on your brakes.

Slipper clutches also have a bad name for bad pulling away but i don't belive there is any reason for this as torque is being apllied in the correct direction.

Any help with be greatly appreciated.

Many thanks
Bryan

[nelly]

I doubt you'll get a definitive answer There are several views on what is right or wrong, but here's my 2p worth.
Firstly, never clean the plates with WD40. Your suspicion is correct. I use brake cleaner.
1 - The copper based friction material you have sounds like that used on aftermarket "sintered" plates. This has a higher coefficient of friction than normal and could contribute to the grabiness you are experiencing. I guess you could class it a "race" mod, certainly a "peformance" one. I use these, and have seen many bikes with them, and wouldn't put them in the "bad" category. There are, as always, good and bad quality ones flying around. I've only used the DP ones, the Bucci or the STM packs.
2 - There's nothing stopping you running a 998 pack. The important thing to watch is the pack thickness. This is increased/decreased by using different thicknesses of plain plates and the thinner plates of the performance kits. These usually run 9 friction plates. Another alternative measurement to that of the pack thickness is to make sure the last friction plate is around 5mm from the edge of the basket. If you're running the pack too thick, you are in effect preloading the clutch springs too much. This could contribute to the grabiness also.
3 - The ST4S clutch pack uses alloy as the base metal of the friction plates. This makes them quieter. The OE friction material is the same as the other standard plates. It uses 7 plates, the same as the majority of the other bikes. It could be used in a slipper, but personally I wouldn't use this in the SPS, because of the power output.

I'm in agreement with you that a slipper should be no worse than a conventional clutch when pulling away, for the same reason you mention.

Make sure also that the basket is not grooved too badly. If it is, dress the ridges with a file to smooth them over.

Have you removed all the dished plates? I'd suggest running at least one. A second is sometimes fitted to reduce/eliminate snatchiness. I wouldn't have thought you'd need more than two though.

Finally, there are a couple of things that can affect the pick up, that are nothing to do with the plates.
First is gearing. Std. Ducati gearing is notoriously high in first. Have you dropped to a 14T front? This helps.
Secondly, make sure the slave cylinder is bled.........as close to perfection as you can get it. This will give more travel on the pushrod and more feel through the lever. If you have very little effective lever travel, then this may be an indication it could be better. Also check that the seal in the slave cylinder is not shot. Pull the slave cylinder off and look for fluid around the piston, even pull the clutch lever a small amount to see if fluid comes from the cylinder. If there is any sign, or doubt about it's integrity, swap it out. I replace them with Evoluzione ones that are far better sealing.

[Bj.O.rn]

The SPS has got sintered race clutch plates as standard.. WD40 or similar products are eften used on the 996RS racebikes I have been spannering on.. it does work on sintered clutches, and doesn't slip even with 170bhp on the wheel..

[Edited on 11-4-2004 by Bj.O.rn]

[Edited on 11-4-2004 by Bj.O.rn]