Dry Clutch Clanking Noise - Where from???

Discussion in 'Technical Help' started by alanp, Apr 4, 2012.

  1. alanp

    alanp Active Member

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    Ok, your initial reaction is - from the plates hitting the clutch basket dummy! Well yes, when you pull in the clutch lever you get some higher frequency but lower noise level from there BUT I'm talking about when in neutral with the clutch lever left alone and the engine ticking over. Under these circumstances there is a different and heavier clanking noise which to many people (and a proportion of Ducatisti as well) is bordering on objectionable. If you stop your engine and rotate the clutch back and forth by hand you will hear the knocking noise coming from inside the engine casing and no way when doing this by hand are the clutch plates hitting the clutch basket since they are all clamped together by the springs. I've checked this on a couple of dry clutch Ducatis and the result is the same.
    So, if the main tick over clanking noise, which goes away when the clutch lever is pulled in, is inside the engine casing is it the primary gears rattling against each other and no amount of dosh spent on new plates/basket will get rid of this noise?
    Maybe, once these dry clutches have some miles on them the 2 bearings holding the larger of the primary gears and the clutch basket behind the clutch basket wears and increases the tooth/tooth clearance between the gears and this causes increased clanking noises? Or, is it gear/gear clearance clanking in the gearbox which goes away when the clutch lever is pulled in with the engine running by reducing the engine pulses transmitted into the gear box? Can the clanking noise be reduced by changing the bearing behind the clutch?
    I don't have hands-on knowledge of the recent Ducati wet clutches or a workshop manual for them to see how their design/construction has been changed but they are quieter, but it can't just be the oil on the clutch because on dry clutches the noise comes from inside the casing behind the clutch.
    Anyone any thoughts on this?
    P.S. This is a technical topic and is not intended to start the 'love or hate the clutch noise debate'
  2. Alan, firstly, what bike are we talking about ? Many older Ducatis had a steel clutch basket and steel plates......and they make an ALMIGHTY racket when they are worn, whatever the position of the clutch lever. There is a ring to the noise too. Secondly, if the plates are worn, then they will still be relatively loose in the the stack, and so the inertia of the engine is quite capable of whacking them against the basket. Look at the basket tangs too, just HOW deep are the grooves in the offending article you are talking about ? I'd suggest a new alloy basket and alloy friction plates would sort the issue, its HIGHLY unlikely to be gearbox related.......
  3. Mr.R

    Mr.R Well-Known Member

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    Hi Alan...Yes it's me!

    As Nog' has said it's the plates hammering into the basket,NO DOUBT about it 100% sure about this one!
    I've moved a 10 min' walk away from where I used to live, but if you Pm me we can arrange a domonstration.
    You'll need to be quick though as I'm waitng on some new Barnett plates to arrive before fitted a new V-Two hard anodised basket.

    Steve R
  4. neilma

    neilma New Member

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    Could it be a loose alternator nut? When I purchased my bike (996) a couple of years ago, the clutch made a right racket. I changed the basket /plates etc but still noticed it was noisy and the ears on the basket were starting to get notches after only a few hundred miles.

    Anyway to cut a long story short, I removed the engine cases over winter whilst servicing the bike and found the alternator nut loose. A new washer (£18!!), a new nut, bit of loctite and 280Nm later, the bike is silent (well, near enough :)

    Its never felt as smooth nor as quiet so I reckon the marks on the inside of the case and the noise was all to do with the nut coming loose.....

    Just a thought.
  5. Hello Steve, glad you found your way in !
  6. 470four

    470four Gone but not forgotten - RIP

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    Vid of my old steel basket getting "donged" :biggrin:

    [​IMG]

    Note incredible resonance with only one "dong"?? No wonder clutches are so noisy getting clobbered several times a second!... its now quieter with an MPL alloy basket.
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  7. Imola

    Imola Well-Known Member

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    Hello Ducati Steve,
    good to see you joined the forum, I'm meeting up with pablo next time i'm down to pick up his high level can's etc.
    Do you fancy a beer or two and talk ducati's all evening ?
    Steve
  8. nelly

    nelly Active Member

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    The lower frequency "knocking" at tickover is the primarys. Yes, the "traditional" rattle comes from the clutch but the primarys are stright cut gears, not helical like most Japs, and the uneven engine pulses cause the knock due to the back lash. Pulling the clutch in, eases the pressure in the gear train and reduces the clank a little. The later bikes use a split, spring loaded primary gear on the crank to absorb the backlash and as a result run much quieter to meet the newer noise regs.
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  9. Mr.R

    Mr.R Well-Known Member

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    Yeah I'll be up for that mate, I've just fitted Pablo's K-Tech Showa's to my 851/916.
    Better make it quick though the Coachmaker's is up for sale and they do the best pint of Doombar in town.

    Steve R
  10. lymo

    lymo New Member

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    Hello Alan P.
    I was searching for this matter, and your question appeared. Yes you are correct that the backlash is also producing noise. The comments you got from the other members are also right; that the friction plates are also hitting the outer drum at idle, even the plate stack is compressed by springs. Therfore it will be 2 sources making noise.
    My bike; a Monster 2006-S4RS, do have the same engine as the 999s, and the increased valve lift on these engines demands large valve clearances. On this engine the heads are pretty noisy too due to that. All of it adds up to a pretty high "music" at idle. It might be OK, but "unnessesay" noise could be reduced.

    I have done some work at the clutch and made devices in the bottom of each recess for the friction plates, so that the inner friction plate is just about resting to a fixed surface in the drum. This solution is giving a slight inward pressure to the drum, which is then trusting inwards on the bearings. This is "settling" the inner side of the visible notches on the inner friction plate towards the drum, so that they do not freely go back and forth at each firing pulse. I have like 0.1mm positive pressure on some special inserts. Going higher will disturb he contact point towards the plate stack as the frictionplate is resting to the fixed point will be distorted a little. I use an ADLER clutch with a DP outer drum.

    BUT, i wish to ask if anyone of you have ever tried to remedy the primary drive gear backlash. I have done some research, and what I find is that the Ducati engines with wet clutch do have a split primary front sprocket. There is a spring loaded section to take up the the dead clearance.
    On most of the Ducati models, this gear do have a conical fit to the crank, and a replacent gear from fixed to springloaded is easy to find, like the one on the GT1000.
    However, my S4RS do have a spline fit for this gear, and the only bike that seems to have the same spline, and spring damping is the Diavel. On this one, the primary gear ratio is the same too.
    2012_Diavel_DucatiOmaha
    ( note that the number of teeth on gears and many details is not correct on the drawings versus real)

    On this Diavel pars catalogue it is good illustrations that seems to show DWG 006, parts 7, 11, 12, 13, 15, as needed for the spline crankshaft versons to convert to "anti-backlash".

    As I now have got a fairly good dampning of the friction plate hammering, the backlash is very well audible, and I recon this would be the right step to go further.

    Any others messing around with something similar, or converted conical fit gears?.

    And I agree with you; leave the "love or hate the clutch noise debate" to a separete tread. This is a very interesting technical matter.

    Ride safely,
    lymo
  11. peter james

    peter james Senior Member

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    FOOKIN hell lads fair play to you, I just ride mine and get baffled when shims clearances and split primary stuff comes into it. ;.)
  12. 900streetfighter

    900streetfighter Well-Known Member Subscriber

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    Suggest louder exhaust reqd.
  13. mcr998

    mcr998 Active Member Subscriber

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    Absolutly :upyeah:

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