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Old 05-Jul-2012, 08:06 AM
JAS749 JAS749 is offline
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Exclamation Dp Slipper Clutch

Morning all,ive fitted one of the above clutches with brand new clutch plates which where put in order for by the guys at jhp.
Took it out for a spin and found out that once it warms up,it makes a screeching/growning noise when pulling away from standstill any thoughts what this could be!!!

I've bled the clutch again and even added an extra plate but the noise is still there.

thanks in advance
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Old 05-Jul-2012, 08:55 AM
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Stealth Stealth is offline
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welcome to the world of the dry slipper clutch.

I had had four different slipper clutches (Bucci, Fast by Feracci, DP and JHP) on two different bikes (996 and 998) and they all do it.

Getting the stack height right is critical to lessen the likelihood of this happening.I seem to recall the clearance at the end of the stack should be 4mm - 4.5mm but there will be experts on this site who will give you chapter and verse.

Bleeding the clutch line does make a difference too.

In short, the first step is to set the clutch right at the beginning so this means getting the stack height right (as described above - don't rely on the plates you have as giving you the right stack height is lesson one).

You could also consider putting in more than one concave steel plate to create more tension in the clutch which lessens the symptom you describe.

slipper clutch plates do wear faster than conventional clutch plates as they get at least a double dose of partial friction activity (i.e. coming apart and together). So a fact of life of a slipper clutch is to check your tolerances every 1000 miles or so.

This constant attention can be a real pain and I am sure there will be those who say that they had slipper clutches that never had this problem. However, I have done over 50 000 miles with Ducati slipper clutches of different sorts and they all do it. The STM design may be better but I have no experience of it.

My initial advice if JHP fitted it is to go back to JHP. Rick is excellent at setting the plate height and will show you what to be done for the future.

If I am honest with myself, the slipper clutch for road use is bit of personal folly given that I only do a small number of track days a year. I have benefited from its use on fast Alpine tours where you are hammering between hairpins but this is hardly everyday!

I am sure I will get to the point that a lightweight clutch will be less of a pain and more of a gain than the slipper. Just my personal view though!

Last edited by Stealth : 05-Jul-2012 at 09:32 AM.
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Old 05-Jul-2012, 09:15 AM
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DSC Region Organiser skidlids skidlids is offline
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Quote:
Originally Posted by Stealth
You could also consider putting in more than one concave steel plate to create more tension in the clutch which lessens the symptom you describe.

There is some great advice for you, I've always found them better with more than one dished plate fitted. That and blowing out the clutch dust with a Air-Line on a regular basis
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Old 05-Jul-2012, 09:20 AM
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DSC Member antonye antonye is offline
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I have the STM Evoluzione 48t slipper in the 748 and it doesn't screech at all.

The previous ramp & bearing slipper that was in it did - it drove me nuts, hence going to the STM!!


I'd rather die peacefully in my sleep like my Grandfather,
than screaming in terror like his passengers.- Jim Harkins

Ducati 748S | Ducati Hypermotard 1100S | 600-620SS DesmoDue Racebike #111 <-- Sold!! | Avanti Race Parts
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Old 05-Jul-2012, 09:30 AM
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Quote:
Originally Posted by antonye
I have the STM Evoluzione 48t slipper in the 748 and it doesn't screech at all.

The previous ramp & bearing slipper that was in it did - it drove me nuts, hence going to the STM!!


Anthony

You may well have convinced me to go for the STM!
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Old 05-Jul-2012, 11:11 AM
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Originally Posted by Stealth
You may well have convinced me to go for the STM!

To compare the two, the ramp & bearing type I had was very harsh - it used to pulse through the clutch lever and also had a definite "click" when you engaged the clutch through the lever. Maybe the basket was a bit worn (and that click was the plates breaking free of notches in the basket) but I did dress the basket to get rid of the worst of the notches and it didn't go away.

We fiddled with the clutch pack, stack height and the dished plate to try and get rid of this but with no luck. It also used to screech as well and we tried to get rid of this as well but the screeching would only go for a couple of days at most and then it would come back.

The STM I have now came up cheap on the site so I bought that and swapped it over, and the difference was amazing! You hardly notice that there is a slipper clutch in and if anything it makes the clutch action lighter than standard.
The action is a lot smoother than the ramp and bearing type.
I've done plenty of trackdays on the 748 (which is all it gets used for now) and it gets plenty of abuse and hasn't missed a beat.

When looking for a slipper for the Hyper I wouldn't consider anything other than the STM Evo 48t model. They are expensive, but they work and work well.


I'd rather die peacefully in my sleep like my Grandfather,
than screaming in terror like his passengers.- Jim Harkins

Ducati 748S | Ducati Hypermotard 1100S | 600-620SS DesmoDue Racebike #111 <-- Sold!! | Avanti Race Parts
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Old 06-Jul-2012, 04:06 AM
gsxr7111000 gsxr7111000 is offline
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I have a slipper in my 999, Just done the plates and set them at 38.5mm.

I never new my bike had a slipper till i took it apart due to slipping. So

The question is how do i test this so i know its working or is that a dumb question
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Old 06-Jul-2012, 05:37 PM
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Jasper Jasper is offline
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Quote:
Originally Posted by antonye
I have the STM Evoluzione 48t slipper in the 748 and it doesn't screech at all.

The previous ramp & bearing slipper that was in it did - it drove me nuts, hence going to the STM!!


+1 from me too.No screeching ever from my STM 48T.
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