How to lighten clutch effort on S4R

[Lukey]

Someone wants to buy my 2004 S4R but she had wrist surgery and says the clutch is too heavy. I told her I'd research options for her. I didn't find a whole lot on the board.

It looks like her options are to remove a couple clutch springs (how much lighter will this make the clutch and are there any drawbacks for normal street riding?) or perhaps to retrofit a newer, lighter setup...(how hard is this and how much does it cost?)

Anything else I'm missing? Thanks all!

[TreyRiser]

I here installing a new slave cylinder should decrease the clutch pull by 20-30% depending on which one you get, but this mod cost a couple hundred bucks... i have also heard removing two springs on the pressure plate can ease the pull, its really easy takes a 4mm an 5mm socket and about 15 minutes...

[stopintime]

From what I read about it, the removal of two opposite springs won't cause any issues. Let her try it this way first. If she likes the way things are going, but still needs more - buy aftermarket slave. Combined, these two mods might lighten the pull by 40-50%.

Both mods have been discussed by people who have done them. Try another search? (lighter clutch pull)

[alexisonfire]

It is true that an aftermarket slave cylinder will reduce lever effort, however, keep in mind that replacing a slave cylinder unit for one with a larger piston typically requires a longer lever pull.  This usually isn't a problem as ducati has provided adjustable levers, but it can be a problem to those with smaller hands (the woman interested in your bike).  I cannot attest to the fact that removing pressure plate springs is safe but if a problem has never been reported I might assume it is.  I purchased an Evoluzione slave cylinder a few months ago.  As advertised, the lever pull was reduced by 20-30%, but I did have to distance the lever from the bar to get a pull long enough to disengage the clutch.

[Slide Panda]

*Edit - gah Alex got the slave info out while I was being long winded.

Yep, your two options are listed above - but here's a couple more details.

Replacing the clutch slave is the more expensive/invasive option and the reduction of pressure needed to pull the lever means you need to pull the lever further to move the slave piston X mm.  One positive side effect of this, is it increases the friction zone in the levers pull, making modulation easier.  The end reduction in effort is dependent on the size of the piston in the slave - I know Evo makes a 28mm and 30mm piston slave.  The bigger the piston, the easier the pull, but the less the piston moves.  usually not an issue, but if air is working into the fluid you'll notice the effects sooner the larger that pistons bore.

Re springs:  It's not uncommon for folks to pull two opposed springs out of the clutch.  It's quick, easy, cheap and should reduce the pull needed by 33%.  The one drawback I can think of is that with a more powerful bike there's a possibility that you'll get some slipping.

Also one thing to consider is the spring weight.  If you've got stainless springs, they require more effort at the lever than the mild steel stock springs.  Some folks who didn't want the increased effort of stainless springs but wanted an open clutch painted the stick springs for some bling and rust protection.  

[vwboomer]

I've got stainless springs. When I removed opposite springs it was fine under moderate acceleration but when whacking the throttle it slipped.
I picked up an Oberon slave cylinder this winter that I have yet to install, but it was only $120 shipped from the factory.
Hopefully I get it on soon. I beat my hand with a hammer a couple weeks ago and it makes holding the clutch quite painful! doh!

[Shazaam!]

New Slipper Clutch

If you're in the market for a new clutch, you might want to consider the new Adler Power Torque Plate Clutch (APTC) that Ducati is now installing on the Monster 620 at the factory. It's a slipper clutch which is suposed to work better than the present ramp and ball slipper clutches but with a 40% reduction in clutch lever pull.

It's offered with steel friction plates for (2001 and earlier model) Ducatis or with aluminum plates for (2002 and later) models that use an aluminum clutch basket. About 1079 Euros.

[Spidey]

Aftermarket slave cylinder.

Take out a coupla springs.

Radial or aftermarket master cylinder  Those brembo billet one are really nice, but a billion $.  See if you can get a cast one rather than a forged one, though IIRC the clutch side is one forged.  Even a stock 999 or 1098 will work well.  Depending on how you ebay, this solution can run $100-$500, probably around $200-$250.

More important -- lots of folks think it's too much at first.  She'll get used to it, even if she's had wrist surgery,.

 

[Shazaam!]

Aftermarket master Cylinders

Sorry, but changing to the aftermarket master cylinders will make it worse.

On the clutch side, the Brembo radial lever increases the master cylinder diameter to 16mm from the stock Ducati 13mm. As the diameter of the master increases, the distance the piston has to move to engage/disengage the clutch decreases, which decreases the distance the lever needs to be pulled.

There are two models of the Brembo radial lever, 16x16 and 16x18. The different last number refers to the 16mm and 18mm pivot-to-piston distance. The stock unit is 20mm.

Both have a 16mm MC that reduces the lever pull distance at the expense of a higher force need to pull the lever. So you get faster shifts, great for a race bike but hard on the left hand on the street. That's the trade-off.

The 16x16 unit has a 4mm shorter (16 vs. 20) than stock pivot-to-piston distance that has the effect of reducing pull distance 17% over the stock 916 unit. It's 21% harder to pull than the stock 13x20 lever.

The 16x18 unit has a 2mm shorter pivot-to-piston distance that reduces pull 27% over the stock unit. But it has a 36% harder pull than the stock unit. It requires the most lever force but has the shortest pull.

If you combine one of these radial master cylinders with a larger diameter aftermarket slave cylinder you'll be able to negate some of this effect but if you use too large a slave cylinder you have difficulty with the clutch plates not moving far enough to fully disengage, so clutch drag and elusive nuetrals can be a problem.

[Spidey]

Interesting.  My seat-of-the-pants experience has been the opposite.  I've found a radial clutch MC easy than a stock non-radial MC, but ya can't argue with math.  Maybe it's because of the shorter distance for pull rather than the effort involved. 

[Lukey]

Well, she bought the bike anyway  (she slept on it talked to her Ducati-riding buddies who told her it was too awesome of a bike to pass up), but I will pass on this info. Thanks, everyone!

[Slide Panda]

Just point her to the DMF.. she can ask questions until she's blue in the face... we've got nothing better to do than answer 'em   

[red baron]

You could alway follow this advice.

Sexual Tyrannosaurus

[DucHead]

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