Clutch Grabs Violently on Fresh Engine

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herbg
Diana
Posts: 50
Joined: Thu Nov 10, 2011 4:56 pm

Clutch Grabs Violently on Fresh Engine

Post by herbg » Sun May 05, 2019 4:56 pm

Rolled the bike out today for the 1st time after a fresh engine rebuild (thanks to Guy Martin of MBP). Once I got it started, I put it in 1st gear and slowly let out the clutch lever while rolling on the throttle.

However, once the clutch handlebar lever was almost fully out, the clutch engaged violently with the bike lurching forward.
A bit startling so I tried it again in my attempt to ride up the driveway. Unfortunately, it grabbed again - this time stalling the engine.

I realize a new clutch might need to be broken in but I didn't expect the "on/off switch" engagement I'm getting now. There is no ability to ease out the clutch while rolling on the throttle - making it impossible to slowly ride the bike.

Clearly something is off. So, before I begin to fiddle around with the clutch adjustments, I'm looking for tips on where to begin and what might be going on. Looking for some guidance on setting up the clutch engagement correctly.

The clutch is a S1425 SURFLEX competition ALLOY clutch kit including springs, alloy friction and steel plates. I'm also using a Brancato extended clutch lever.

Any idea on what might be going on?
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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Craig in France
Cagiva Gran Canyon
Posts: 872
Joined: Tue Mar 23, 2004 3:58 pm
Location: Montpellier, France

Re: Clutch Grabs Violently on Fresh Engine

Post by Craig in France » Sun May 05, 2019 11:32 pm

Well, it's basically the springs that control the clutch engagement, so that's where I'd look.

Also, you say you've fitted a competition clutch (why?), and that probably explains things a bit too. If you gave it more revs, it probably wouldn't stall. But it will send you down your driveway like a bullet. Which is kinda the idea ...

herbg
Diana
Posts: 50
Joined: Thu Nov 10, 2011 4:56 pm

Re: Clutch Grabs Violently on Fresh Engine

Post by herbg » Mon May 06, 2019 7:53 am

This is normal behaviour for a competition clutch? There's nothing on Steve's site that says this is "Not for Street Use":

https://store.bevelheaven.com/Engine-Re ... quarecase/

I assumed the "competition" part refers to the "alloy" - thus lighter and less centrifugal force.

I'm thinking it has something to do with the setup of the clutch (adjustments, etc) BUT, not having any experience with this clutch, I am prepared to replace it. UGGHH !!
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

ducadini
750 Sport [BEVEL]
Posts: 247
Joined: Sat Jul 31, 2004 9:54 am
Location: Antwerpen

Re: Clutch Grabs Violently on Fresh Engine

Post by ducadini » Mon May 06, 2019 1:24 pm

I think We can find the reason in the first sentence :
Rolled the bike out today for the 1st time after a fresh engine rebuild
With new clutchplates and springs and a new setup (extented lever) it was SURE to get exciting :-D :-D

Give the plates some time to oil up and VERY probably it will become softer to control.

I don't recall anyone saying that using a Ducati for daily use with some "competition" parts in it was easy.
Fitting some Blue/white cams just made it more exciting :-D :-D :-D :-D

Anyway : happy to see You're using the bike, hope You get used to using it's potential.

ciao
ducadini
Nego i ricordi peggiori
Richiamo i migliori pensieri

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geodoc
750 GT
Posts: 177
Joined: Thu Jul 18, 2013 3:57 pm

Re: Clutch Grabs Violently on Fresh Engine

Post by geodoc » Mon May 06, 2019 10:45 pm

Not saying that my clutch problem cure would also cure yours, but. After I got my GT engine back from a complete re-bop by Guy, the clutch stuck & grabbed horribly. I tried all manner of things to rectify with no effect. Finally, in desperation I took one of the steel plates and even though it looked flat enough checking against a glass surface, I shot it with machinist blue and sanded it with 600 wet or dry emery paper on plate glass. It was pretty flat, but not quite perfect. I ended up taking all the plates and wet sanded them on both sides until they showed perfectly flat with the machinist blue, re-assembled and the clutch then worked perfectly. I had a stock clutch with Surflex plates.

I fall else fails ....................




.

jockduck
Mariana
Posts: 31
Joined: Sun Jan 17, 2010 3:21 am
Location: South Australia

Re: Clutch Grabs Violently on Fresh Engine

Post by jockduck » Tue May 07, 2019 4:51 am

Sorry to hear of your problem but I also have similar problems with the Surflex upgrade kit, I grabs badly when cold improves after a few kilometers and is normal once the engine is at normal working temp BUT then it slips when giving the motor a handful at 4000+ rpm, my other two bikes have stock clutches and behave well, I'm thinking of swapping back to stock if I have enough bits.
Jock

wdietz186
Cagiva Alazzura
Posts: 700
Joined: Sun Sep 10, 2006 5:40 pm

Re: Clutch Grabs Violently on Fresh Engine

Post by wdietz186 » Tue May 07, 2019 7:13 am

You might try soaking the plates in engine oil for a couple of hours, many clutch materials need to be fully saturated to work properly.

herbg
Diana
Posts: 50
Joined: Thu Nov 10, 2011 4:56 pm

Re: Clutch Grabs Violently on Fresh Engine

Post by herbg » Thu May 09, 2019 4:36 am

All very good suggestions. I spoke with Guy Martin on Monday and told me the clutch is probably sticking from sitting all winter. He did say that he test rode the bike extensively before it was shipped back to me and, while the clutch is a bit more aggressive, he had no difficulty negotiating stop-and-go traffic with the bike.

He gave me a few tips to try to "unstick it" so I'll give that a go when I get a chance to get back at it. Last resort, he also suggested taking the clutch cover and pressure plate off to inspect the plates. Hopefully, I don't have to resort to that.
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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