Clutch Issues -- Lazy question Help needed

[englishstiv]

Hi folks okay so my clutch issues persist.

I have tried various configurations but not done a site search yet (the lazy part I know!).

Also tried the touch of oil on the plates as suggested in another post and from other site searches.


My problem is I have a very noisy clutch .... very, very noisy and it also is very snatchy at slow speeds through the gears. It also makes a proper racket on deceleration or throttled back at slow speeds.

The lever and slave cylinder work perfect so issue is not there.

I have not swapped the cage yet but would like to put the Q out there and see if anyone could suggest a remedy / cause or maybe an enlightened view as to where I might be going wrong.

How many Friction and Steel plates should there be in the housing, could there be a bearing issue, is it likely to be the Cage ?

Any measurements would be appreciated to work with

Could it be something wrong elsewhere and the clutch is getting the noisy feedback ?

I am away all week working so won't see this post till at least Friday 7th so you have plenty of time to offer your thoughts

[MarkST]

Also tried the touch of oil on the plates as suggested in another post and from other site searches.

Lithium Spray Grease. I don't recall anybody ever suggesting oil on any of the forums.

My problem is I have a very noisy clutch .... very, very noisy

Sounds to me like the tangs on the plates and grooves in the basket are very worn. If this is the case, then they do make a right proper racket at this point.

and it also is very snatchy at slow speeds through the gears.

I'll guess then that you have a 'closed' cover on it ? You tend to get a build up of friction material off the friction plates in there with a closed cover (very fine dust) and this is what makes for the graunching. An open cover, or jacking your standard cover out with washers between the cover and the main engine casing will allow all the shit to escape, and hopefully see an end to the graunching.

I have not swapped the cage yet

Is this a fancy name for the basket, or is this some other mysterious part that I've never heard of before now ?

How many Friction and Steel plates should there be in the housing

Assuming it's the same as the later bikes, there will be 8 x 2mm steels, 1 x 1.5mm dished steel, and 7 frictions.

The stacking order from the back of the basket is . . .

2mm steel
1.5mm dished steel with the punched dot facing outwards.
Friction
2mm steel
Friction
2mm steel
Friction
2mm steel
Friction
2mm steel
Friction
2mm steel
Friction
2mm steel
Friction
2mm steel

The stack height should be 38mm +/- 2mm

There is such a modification as 'The Quiet Clutch Mod' which involves starting the pack with an old friction plate at the back, and then removing either/and/or steel(s)/Friction(s) at your own discretion to get the correct stack height.
This is how I have my ST4 and my ST4S clutches set up, but they're a reet bastad to get set up right, and can involve disassembling and reassembling the clutch pack many times to get it just right.

I hope that this is of some help.

[higgy]

+1 quiet clutch takes some time but it does the job

[Derek]

+ 2 on the quiet clutch. My ST4s did 39,000 miles on the original clutch with it done. I've also done the 907.
What is the state of the basket and the tabs on your plates Stiv? Sounds to me like they could be very worn.

[MarkST]

The quiet clutch mod with lots of reading (not my words - copied and saved some years ago)

A quiet Ducati clutch, the easy way!


The following modification is based on my experiences with a ‘99 ST4 clutch, initially using an OEM basket and centre/hub plus an aftermarket plate pack, and subsequently an OEM centre and Charlie Smith/Procutting clutch basket with matched Barnett plate pack.
Other members of the Yahoo LiST have tried it with success, but we have not researched into whether it can be applied to every possible combination of OEM and aftermarket components. It is important, therefore, that you understand the principles before starting work. As with any modification, there are always pros and cons, so you do it at your own risk!



Ducati’s dry clutch has good ‘feel’ and works well, its one main advantage over the wet clutches of other manufacturers being that dust from the friction linings does not contaminate the oil. Theoretically, the absence of friction-reducing oil might also make it possible to use lighter clutch springs, but no Ducati rider has ever seen evidence of that! Given there is no need to keep oil inside the unit, it can be run open to cool it and give it a racier look, but that is when its major attribute becomes really evident. It is loud!!

Not a problem when the engine is actually driving the rear wheel, a heavy knocking noise is apparent when idling in neutral, and is sufficient to be quite offensive to those of a sensitive nature. (We shall ignore riders who proclaim that ‘loud clutches save lives’, as they are confused souls…) Whether the noise is objectionable or not, that mechanical mayhem does no good to the clutch itself, such that some owners prefer to ride the bike gently as it warms up, rather than let the clutch hammer itself apart.

The noise is directly related to the dry status of the Ducati clutch, as there is no oil film to cushion necessary play in the unit. The infrequent and uneven power pulses from the beloved vee-twin also make it worse than would be the case with a four-cylinder engine, plus the Ducati is sports-orientated and does not carry a massive flywheel that would damp the pulses better.

The knocking actually comes from the clutch plate-pack rocking to and fro in the slots of the clutch basket. The closer the clearances, as with the fabled Charlie/Barnett set-up, the quieter the unit, and having alloy tabs running in alloy slots is less resonant than with the original steel on steel. However, sooner or later, the clearances will open up with normal wear, and the knocking starts…

Several commercial suppliers have hit on a method of preventing the to-and-fro fretting of the plate-pack in the basket, and the method outlined below is based on personal experience of one of them, which utilised a special plate pack mated to the OEM ST4 basket and centre. The difference with the quietening mod that follows is that it requires nothing more than the addition of a couple of junk plates, and no machining or special components at all.

Basically, it consists of incorporating the equivalent of a rotary friction damper to bind the entire clutch unit together, (centre, plate-pack and basket) when the clutch is fully engaged. It has no effect on clutch action, but there are some theoretical mechanical/wear disadvantages that probably explain why Ducati themselves have not adopted it. (There is some evidence that Ducati did utilise it at one stage of 900 production, perhaps also with the Paso, but they seem to have abandoned it subsequently).

I’ll outline the theoretical disadvantages later but, rest assured, clutches modified in this way have given many thousands of miles of trouble-free silent service.

_____________________________



So, a step by step procedure that can produce a quiet clutch in minutes is as follows. I assume that all home Ducati mechanics are able to gain access to the clutch and remove and replace the plate-pack correctly. For this job, there is no need to remove either the clutch centre or the basket, both of which require special tools.

Before you start, you will need to find two old friction plates, preferably of the OEM ST2/ST4 steel type, as they are stiffer than the alloy friction plates of the OEM ST4s.



1: Remove the pressure plate and springs, and take all the loose plates out, keeping them in the order of removal. Inspect the edges of the tabs on the friction plates, and the sides of the basket slots. There, you will likely see the wear caused by the tabs slamming to-and-fro in the slots. If the slots have deep notches in them, a new basket may be needed in the near future, or smooth engagement could be compromised by the tabs sticking in the grooves. I think there is little to be gained by filing the burrs off the tab sides, as this just reduces the contact surface-area again.


2: Drop one of the old junk friction plates into the basket first, pushing it right down into the slots. As the tabs on the plate reach the radiussed ends of the slots, they will lock into the curve while pressure is applied, and cannot rattle to-and-fro. This is the first significant aspect of the mod.


3: Then add the second old tabbed friction plate.


4: Now slide the first plain steel plate onto the clutch centre and push it as far in as it will go. For the quietening mod to work, that steel plate has to contact the face of the previous friction plate before it hits the bottoms of the splines/slots on the centre. The amount by which the friction face protrudes needs only to be around 0.020”/0.5mm, and more will not be better. This dimension will likely be different with the various options of OEM and aftermarket components you might be using, and is also influenced by any wear on the front face of the clutch centre. Checking the amount of overhang will require a short straight-edge that can be laid across the friction faces adjacent to the roots of the slots in the centre.


5: Replace all the other plates as they came out, including the cone-shaped spring-plate, whose exact position and orientation does not seem to be critical. (Note that the wave-profiled spring plate in the Barnett plate-pack gives more resilience, and may be a factor in abolishing the famous ‘groan’ on take-up. Refacing your stock plates can apparently work too).


6: Disregarding the extra two plates in the bottom of the basket, your effective plate-pack thickness should only have increased by that 0.020”/0.5mm mentioned in 4 above. This should mean there will be no issues with plates coming out of the basket slots or off the centre when the clutch is disengaged, especially if your plates have seen some use. However, you should check this before running the bike. The specified max thickness of the pack is 38.5mm, but a mm or so less is permissible.

If you have to juggle with plates, remember that different brands vary in thickness and number, and I see no problem with mixing-and-matching plates to get the right total thickness. If you find it difficult to get down to the 0.020”/0.5mm overhang, you could always reduce the thickness of the friction material on the two additional plates, but do it evenly on a flat surface to keep the outer surface square to the rest of the components. Finally, make sure that the very last plate you put in is a plain steel one for the pressure plate to contact.


7: With the clutch back together, and the springs seated and tightened carefully, test the action without the engine running:-

A: Pull the clutch lever right in with one hand, and then gently rock the pressure plate with the finger-tips of your other hand. You should see that all items (pressure-plate/centre, plain plates, friction plates and basket) are free to move independently, within their limits of play.

B: Now start releasing the lever while still rocking to-and-fro. You will see the pressure-plate and all the plain and friction plates start to bind and move as one, but that unit will still rock within the slots of the basket.

C: As you let the lever out finally, you should see that the whole unit goes solid, such that the tabs will no longer rock within the basket slots. Any remaining movement is now inside the gearbox.


8: Replace the clutch cover and start the engine in neutral. Silence!!

Now test-ride the bike with caution to check that you can find neutral as easily as before. The dimensional change with this mod should be compensated by the hydraulic actuation, but there will be slightly more lost motion as the plates bed and flex a little. If you have a problem, either abandon the mod or check ways of increasing clutch lever travel by incremental adjustment of the lever screw (Caution!), bleeding the hydraulic line or bending the lever blade out.




Now to the theoretical drawbacks of this mod.


A proportion of the clutch spring end-loading is now being transferred to the basket, which means that the bearing in the back of the clutch basket mount is seeing an unfamiliar endload.

In addition, action and reaction results in loading of the alloy clutch centre against its steel retaining washer, which interface is dry. The clutch centre incorporates the cush-drive rubbers that smooth the power pulses, especially at low speed, and this loading could reduce the effectiveness of the cush mechanism and accelerate wear at this point. Personally, I can detect no difference in the feel of the power pulses before and after the mod, but there will be more wear as the centre and retainer fret against each other. Perhaps a PTFE shim at this point might be a good idea…

I feel the wear issues are genuine, but I choose to believe that they are not significant. Many Ducati riders have covered substantial mileages using one form or another of this modification without problems, and I’m sure all would agree that the silence and reduced wear on the clutch tabs and slots are well worth the risk. In any case, it will take only minutes to revert to standard, should you come to decide otherwise.

[Mc tool]

Lemmme tell ya sommat
1/ I put new basket and plates in my SS ( same clutch as the 907 ) and it didn't make a shit of difference noise wise ( well maybe a mouse sized turd of difference but that's it ) , and my basket and plates were as rooted as any I have seen , but quiet as after the clutch mod
2/If you put the extra plate in correctly stack height wont be affected .
3/ the 906 clutch has axial loading on the clutch support bearings all the time ...... no problem

Check the pic and you can see I have bent the tangs on the xtra plate. What I did to get correct "adjustment " was to fit this plate 1st ( tangs facing bottom of basket ) , this leaves the plate way more than the .5mm mentioned above , assemble the rest of the clutch as usual and then ( plastic hammer )hit around the circumference of the pressure plate .... this will tend to straighten out the over bent tangs until the 1st steel plate is now resting against the flange at the back of the clutch centre as normal , there is however enough spring in the xtra plate to provide the friction required to stop the backlash that is the rattle . The only tricky bit is that the tangs need to be bent reasonably evenly.
To those of you that have worn plate tangs / basket slots , do the mod before buying new parts ........it will be so quiet you probly wont bother with new bits . If the clutch still rattles the tangs aren't bent enough , if the clutch drags and feels weird the tangs are bent to much , and the difference between to much and not enough is probly around .5mm so take care not to "overshoot" while adjusting.
Done properly it works #$%king brilliantly

[MarkST]

Very interesting Mc tool, I've not heard of that before. Where did that idea come from?
Is that a steel plate or an alloy plate with the bent tangs ?

Also, to clarify, do you just have the one extra friction in the back of the pack, and not two ?

[Mc tool]

steel plate MarkST , it has more spring than the ally ones , tho if I only had an ally one Id give it a go . Reading others experience I saw some peeps used 1 xtra plate and some used 2 , in my instance the correct thickness needed was part way between 1 and 2 plates ( the basket shown is the new one I un-installed when it was no quieter than the old one . the old one had square bottoms in the basket grooves rather than the round ones in the pic )so using one plate only I started bending the tabs back and forth , trying to get the right tweek ..........before I hit on the idea of beating it with a hammer ( actually , its not the 1st time Ive had that idea about uncooperative inanimate objects )and you only have to hit it hard enough to bend the tang a wee bit at a time . Whoever said about venting the dust out of the clutch housing was bang on the money. Once I had my clutch quietened and decontaminated , sureflex sintered plates in there it was as good a clutch as any I have used , even behaved in traffic and handled a hard launch easily

[angelix]

mmm... I would get worried the day my dukes stop making noise and spitting oil...

[MarkST]

Check the pic and you can see I have bent the tangs on the xtra plate. What I did to get correct "adjustment " was to fit this plate 1st ( tangs facing bottom of basket )

More clarification required please - so you're saying that you put the plate in the other way round to how it is in the pic, with the bent tangs facing inward/towards the back of the basket ?

and then ( plastic hammer )hit around the circumference of the pressure plate .... this will tend to straighten out the over bent tangs until the 1st steel plate is now resting against the flange at the back of the clutch centre as normal

and then once all the rest of the plates including the pressure plate are installed, you twat the whole kit and kaboodle with a (plastic) hammer, thus bending the tabs back to where they were in the first place before you bent them ?

Only asking, because I always have difficulty selecting neutral with the mod, and will try pretty much anything to get around it.

[Mc tool]

Yes ( sorry ) other way to whats in the pic . . The tangs were still bent but not as much as shown in the pic , probly less than 1/2 the bend you see , but I think each bike may be a bit "individual " . The only reason my plate tangs are bent is coz 1 plate wasn't thick enough to do the trick and 2 plates was to much . I would think that if your having trouble getting neutral then the extra plate(s) is to thick , but maybe by only .25-.5 mm. I would disassemble clutch , put in your extra plate(s) then fit the 1st steel plate and see how far from the flange on the back of the hub that steel plate is . Ideally the extra plate(s) should be holding that 1st steel plate clear of the hub flange by .25 - .5mm ..... not sure what the exact measurement should be but you need less than what you have ( faaaark ! how scientific is that ? )

[blazing928]

cant comment on the noisy clutch, though I thought common folklore is that a jingly clutch is caused by a worn basket & plates.

I fitted a MPL slipper, very nice it is, thank you, with Barnett plates. They did start to slip, so a clean with brake clean & 2000 grit sand to remove the glazing soon fixed it, been fine ever since.
I didn't know whether to clean off the coating they come with or not, so initially I had only wiped them clean.

I have read that an open basket can allow stones/grit to enter & catch or jam up the clutch. Anyone ever actually found this to happen?
In Victoria some cops have pulled up bikes & issued an un-roadworthy certificate as they say its dangerous; some kid or imbecile might put their finger, or other digit, into the spinning basket!!!
This has been challenged as its not part of the ADR rules or part of a roadworthy [MOT]
As I mostly tour on my bike Ive kept it locked up to keep the stones, rain, olio, kangaroos & digits out.

[higgy]

Only issue I have ever had with an open clutch is from water and then only if the bike is put away wet with Barnett type clutches which tend to glue themselves together if you don't dry them well before putting the bike away

[englishstiv]

"MANY MANY THANKS FOLKS"

This is gonna take some digesting and really appreciate your input with this issue.

Re a few Q's just for the record.

Yep the Cage = Basket it's force of habit due to a former employment working term ----- I knew what I meant

Oil = yep the lithium grease.

I have a light aluminium and very open clutch cover in fact you could compare it to a G-String against underpants so I know I will obviously have a lot of noise due to that.

So looks like I will be busy in the Garage this weekend but not until I have enjoyed this lovely Sunny warm UK weather today.

[MarkST]

Take a look in the parts list in the document section - that will show you the clutch parts.

In terms of discs, according to the parts manual there are . . .

1 x 19110141A Driving (Friction) Disc
7 x 19110151A Driving (Friction) Discs
7 x 19010011A Driven (Steel) Discs
1 x 067516530 Disc (non-specified) - On my 750 the clutch is quite different, and one of the discs is steel on one side and friction on the other. This may be like that.

The 907 appears to work the same way as the later bikes I mentioned, with the slave on the left of the motor pushing a rod through the motor to the other side and disengaging the clutch - so you should be able to do the quiet clutch mod. I'm not quite sure how it would pan out on the 750, and I have no idea yet about the 906, simply because I have not yet viewed the parts list for that model.

Yes the weather's great, and I'll be out on the ST4S later : )

Good luck and keep us up to speed.