Heavy Clutch

Many find that an Oberon slave cylinder helps: http://www.oberon-performance.co.uk/acatalog/Ducati_Clutch_Slave_Cylinders_DCSC.html

You might consider fitting a Venhill clutch hose: https://www.venhill.co.uk/partfinder/search/vehicle/id/1838

 

If you use an after market slave cylinder you will lose some travel of the push rod which does not disengage the plates fully.
Some gents in the US take off 2 opposing springs out of the six. They have not reported any slippage.
I took a 3rd root and went to a local shop, and ordered 6 springs of same material, same length and number of spirals, but smaller wire diameter.
It has worked fine for the last 3 years I am running this set up.

 

I think Stelbo's scheme of fitting lighter springs is a better idea than simply leaving out two; uneven force on the clutch plates seems a bad idea in principle. My worry would be increased likelihood of clutch slip, not only under hard acceleration but through slower locking-up after normal gear changes.

The point about less push-rod travel is of course true, although I have to say that it didn't lead to any problems when I fitted an Oberon to my ST2. As far as my experience goes, failure to disengage properly is more likely to be a problem if the splines on the clutch basket are shot (see picture).

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I ran my 916 with only 4 springs for years with no slippage problems. I have a larger slave cylinder fitted to both of my bikes which are fine and reduce the pull (a little) but removing 2 springs makes it much lighter and is obviously cheaper than a new cylinder.

 

even a strip to investigate and clean might help, could be a binding or bent/damaged pushrod even.

 

was the action lighter with the old plates? if so, then more than likely it's the new tangs on replaced plates that are snagging more on the wear ridges on the cage (as mentioned) and drum. Do you think there's a chance you have aftermarket clutch springs? originals will be dull and matt in appearance. Many of the aftermarket springs in stainless were a higher spring rate than standard but this rarely got mentioned. It's worth trying the "4 spring" mod as works most times without slipping.

 

Reducing the stack height will reduce the preload on the springs and give you a lighter lever

 

Do not do such a thing.
The clutch pack thickness from factory is 38.5mm. Service limit is (if I am not mistaken 38mm)
Measure the total thickness just to be sure.
Your initial post refers to heavy clutch and no drugging.

 

Before you do too much clutch plate juggling, or go and buy a new slave cylinder, remove the existing slave cylinder and carefully pull out the rod that passes through the heart of the engine to the other side.. After more than 20 years of clutching, there's almost guaranteed a build-up of clutch powder, grease and clag stopping the rod from actuating smoothly and without resistance. Clean the rod and scrape/blast/wash out the 'tunnel'.. then evaluate the clutch pull before searching for other remedies

 

Stack height and plate order are not as arbitrary as some would have you believe.
After replacing my friction plates, I had severe clutch drag and was told that my stack height must be too high. I therefore kept reducing the stack height but without success.
I discovered for myself that the drag was caused by the new plates binding in the basket slots and cured it by putting some of the old friction plates back at the top of the stack in place of those new plates.
However, during this process, I discovered that my crazy-low stack height gave me a very light lever. I fully expected the clutch to slip but it didn’t and still doesn’t.
It is important though not to exceed the recommended stack height, as this can lead to the top plate jumping out of the basket.

 

Good luck

 

I sell them, if you want to try one and pay later after you fit it, let me know.
https://www.rsrmoto-europe.com/collections/kupplungzylinder

 

If I would have seen this on Monday I wouldn't have fitted an Oberon this morning! Aaarrrrggggghhhhhh!