Oberon clutch slave

[Brendan S4]

Hi,
thinking of fitting one of these to my S4, what's everyone's thoughts? are they worth the outlay or not much better than standard. My clutch can be a bit snatchy and heavy, looking at reviews etc these seem to help the problem.
Cheers, Brendan.

[jerry]

I have an Oberon on both my S4 and M750 , much nicer pull than standard about 25% less effort

[Brendan S4]

Thanks Jerry,
the more I read about them I think it would be a worthwhile upgrade.

[Flip]

Made little to no difference to the feel of my '97 900's clutch. They do look nice though.

https://s20.postimg.cc/rt9vf9i4d/Slave_Cylinder.jpg (https://postimages.org/)

Obviously my original slave cylinder was of the earlier design to the S4's and it was so long ago when I had one of those that I can't remember if there was a difference between that and the 900's.

Here's a good little read about pull force and movement distance from Avanti:

http://www.avantiraceparts.co.uk/page.php?id=12

[Luddite]

I've had an upgraded slave cylinder on both my S2R 1000 and 1100 Evo; Ducati Performance on the former and Oberon for the latter. They made the clutch pull lighter on both bikes but I think I noticed it more on the S2R as that had a heavier clutch to start with.

I can certainly vouch for the quality of the Oberon, lovely billet construction, a perfect fit and faultless performance over the last seven years. The larger size cylinder means a longer pull on the lever is needed to fully disengage the plates. I've got aftermarket ASV levers with a wider span adjustment than standard so that's not a problem.

If you do change, just to satisfy my curiosity, try using a spring balance/luggage scales on the lever with the standard cylinder to see how many kilograms pull you need to disengage the clutch then do the same again with the new cylinder. Let us know what the difference is.

I think the Oberon model you need is the same as mine - CLU-0116. Don't worry about spares - Oberon offer a lifetime guarantee and will repair/refurbish the cylinder as necessary.

[Brendan S4]

Thanks for the input. Reading what you posted from Avanti gives another perspective regarding clutch lever span etc and longer release, suppose I won't really know unless I bite the bullet and buy one.

[Mr Gazza]

You could fit a pinned clutch pushrod at the same time, which will prevent the pushrod from spinning. That should in turn prevent the slave piston from revolving, which might improve seal life.

Pushrod Part No. is 11721122A

The journey to discovering this is chronicled here.. http://www.ukmonster.co.uk/monster/showthread.php?t=56050&highlight=oberon+slave+leaking

[Chriswilly]

Fitted an Oberon to my 907ie and found no differance at all.

[Dukedesmo]

I have an Oberon slave on my Monster but it also has an RCS master cylinder (16mm) which probably skews the results? as the clutch is lighter than that on my 916 which has an 'Evoluzione' slave cylinder that I believe is a larger bore than the Oberon?

Anyway, in the interest of science I recently did a clutch pull (weight) test to compare them, results were;

M900 with Oberon slave and RCS master = 6.7kg
916 with Evoluzione slave and standard master = 7.6kg

I'm not sure what standard clutch pulls are but somewhat heavier than the above.

Oh, and just for fun my Moto Guzzi Le Mans with standard cable operated clutch = 10kg. :eyepopping:

[Flip]

I have an Oberon slave on my Monster but it also has an RCS master cylinder (16mm) which probably skews the results? as the clutch is lighter than that on my 916 which has an 'Evoluzione' slave cylinder that I believe is a larger bore than the Oberon?

Anyway, in the interest of science I recently did a clutch pull (weight) test to compare them, results were;

M900 with Oberon slave and RCS master = 6.7kg
916 with Evoluzione slave and standard master = 7.6kg

I'm not sure what standard clutch pulls are but somewhat heavier than the above.

Oh, and just for fun my Moto Guzzi Le Mans with standard cable operated clutch = 10kg. :eyepopping:

Not sure how they measure up- according to Avanti the Evoluzione slaves come in 27.0, 27.5, 28.5 and 30.5mm presumably depending on model and year while Oberon state theirs is 29.0mm diameter for all Ducati models and years.

I measured my 900 with the same balance scales I use to set my timing belt tension and got a similar figure to you (which I know is not much good without a standard set up to compare it with) while my little race bike was easily up to 10Kg before the lever started to move, which was possibly partly down to a bit of an awkward angle so I'll pull the bike out and have another go at the weekend as I'm intrigued now but it is a little clutch with strong springs- but it sure don't slip though :biggrin:

[alan s4]

Doesn't need to be Oberon, I bought a "factory racing" billet aluminium from ebay for £35.00 delivered. Someone on here posted a link (can't find it!) and a few of us purchased. Improvement over original for a 1/3 of the price for Oberon.

I'm not far from you in Glasgow, if you want to pop over for a pull of mine (no smart ass comments please:mand:) then feel free..........

[Murray Mint]

Thanks guys, just orderd one of these, http://www.factory-racing.uk/index.php?route=product/product&path=25&product_id=50 Ill let you know how I get on.

[Darkness]

Thanks guys, just orderd one of these, http://www.factory-racing.uk/index.php?route=product/product&path=25&product_id=50 Ill let you know how I get on.

Pretty.

So you won’t be going for anti-rotation with that one, but it’s quite a bit cheaper than the Oberon.

[Mark64]

Made little to no difference to the feel of my '97 900's clutch. They do look nice though.

https://s20.postimg.cc/rt9vf9i4d/Slave_Cylinder.jpg (https://postimages.org/)

Obviously my original slave cylinder was of the earlier design to the S4's and it was so long ago when I had one of those that I can't remember if there was a difference between that and the 900's.

Here's a good little read about pull force and movement distance from Avanti:

http://www.avantiraceparts.co.uk/page.php?id=12

Lovely bit of lockwiring there, the devil's in the detail 👍

[Mr Gazza]

I have an Oberon slave on my Monster but it also has an RCS master cylinder (16mm) which probably skews the results? as the clutch is lighter than that on my 916 which has an 'Evoluzione' slave cylinder that I believe is a larger bore than the Oberon?

Anyway, in the interest of science I recently did a clutch pull (weight) test to compare them, results were;

M900 with Oberon slave and RCS master = 6.7kg
916 with Evoluzione slave and standard master = 7.6kg

I'm not sure what standard clutch pulls are but somewhat heavier than the above.

Oh, and just for fun my Moto Guzzi Le Mans with standard cable operated clutch = 10kg. :eyepopping:


I remembered this post and was determined to measure my bikes when I could find a spring balance.

So I found one in good old lbs.

M900Sie with Oberon slave and Goldline master.. 10lbs. Or 4.53kg.

Commando with cable, but not routed under the tank, just sweeping in one big arc from lever to gearbox... 22lbs. Or 9.97kg.

If the cable is pulled into any sort of shape other than the smooth sweeping arc, (as it would be when properly installed) the effort rises dramatically!

The Goldline master is 13mm. Oberon slave piston is 29mm, which I think gives a mechanical advantage of 6 (from memory.. I'm not going to work it out again!).
FactoryRacing slaves are 31mm btw.

I suggest that your RCS master @16mm, is producing less mechanical advantage (but more clutch lift). Hence the slightly heavier pull than mine.

Interested to see what a standard slave and master weigh in at....

[Dukedesmo]

I suggest that your RCS master @16mm, is producing less mechanical advantage (but more clutch lift). Hence the slightly heavier pull than mine.



Interesting, there are 2 settings on the RCS: The cylinder is 16mm bore but there are both 16 and 18mm pivot/lever settings. On the other (lighter) setting it pulls around 5kg but you do need to pull it all the way in to get a good plate separation.

Also I'm finding it difficult to get a consistent reading with the digital gauge that I'm using and it could well read differently with another (yours?) so, like dyno readings they may not be directly comparable but there is a noticeable difference between the two settings which I suppose is one selling point of the RCS masters.

[Mr Gazza]

That is interesting. since the leverage that the handlebar lever exerts upon the piston, has it's own mechanical advantage, which should be taken into account when calculating the overall Mech adv.
So by applying more leverage to your larger piston, a similar mech adv. to that of my 13/29 set up is achieved. A higher mech adv will always produce less lift by it's nature.

The mechanical advantage of most cable systems will always be fairly similar to hydraulic systems in terms of lever travel to clutch lift. Unfortunately cables suffer from huge amounts of friction within, which is compounded by curves and poor lubrication. This is why they need more effort to pull, not because of poor mechanical advantage.

BTW I used an old brass spring balance with a sliding scale. I simply pulled the lever to about half it's travel with the balance and then held to take a steady reading.

The Commando uses a somewhat unique (in motorcycles) steel diaphragm spring, cut into central "fingers". This has the bizarre property of exerting a varying pressure at different points of it's deflection. It creates an "S" shaped graph of it's pressure as it goes beyond the "flat and pops the other way.
The trick of setting them up for a light clutch operation is to get the sweet spot of the spring by tuning the stack height..... Different strokes eh?

[Dukedesmo]

Sometimes 'old school' is better, I have an old brass engineering spring balance but it only goes to 5lb. The electronic one (designed for airline luggage weighing) sets and stores the weight after a couple of seconds but it's difficult to get a true reading that quickly due to the bars being in the way etc.

One useful way of reducing clutch pull though is to remove 2 (or even 3) springs from the clutch.

I ran my 916 with 4 springs only for several years and combined with the larger slave it was so light a small child could have operated it, never slipped either.