Since installation of a Bucci Slipper Clutch in my SPS about 500miles ago, I have always found it to be a bit grabby/graunchy on pulling away. Once on the move it is absolutely fine. I intend to strip it out at the weekend to check the plate stack height, grease the balls n' ramps etc. I know this has been asked many times before but... - What is the optimum stack height? - How is this measured - plates installed or "on the bench"? - I seem to remember seeing a picture of plates installed in the drum with a measurement being taken of the amount of protusion of the plate stack against the drum - what is that and how is it measured? Any useful info would be much appreciated. Thanks, R
the Search engine works very well since update R - top thread is quite good if controversial in parts :- http://ducatiforum.co.uk/google.php...arch.php?searchid=148&ref=&ss=3926j1539616j12
If it has a tight biting point (not able to feed it in progressively) then it's usually down to the dished plates being not dished any more, or non-existent. These act like springs to make feeding the clutch in/out a little more progressive than being like an on/off switch. You may want to check your plates to make sure that you have the steel dished plates, that they are fitted the right way round (dot-punched on the concave side - although that's not as important) and that they're still dished. According to the BUCCI fitting instructions I have (on the website if you don't have them) you need: "Race" pack: 9 sintered drive plates (should be >= 22mm stack height), 4 convex (dished) driven plates, 5 flat driven plates Note: There's also an additional spacer that you need to fit behind the centre nut if you're using the "race" pack. "Road" pack: 7 drive plates (@ 3mm), 1 convex driven plate (@ 1.5mm), 7 flat driven plates (@ 2mm), and should be >= 36.5mm stack height
Yep, 36.5mm as Ant says. I find new plates always need to bed in and can whine a bit when new. I also give them a light skim with fine emery when fitting.
Antony/Boots, What exactly is the 36.5mm measured against? Is it the full pack - steels and frictions? Antony, I have the BUCCI instructions from your site - thanks. Not sure right now whether I have Race or Road stack. As far as I remember, I agree that the race instructions include a spacer but I think it's just a tab washer to lock the centre nut. It doesn't effect the plates etc, just stops the nut falling off.
I always build slippers up with 4-5mm of drum protruding past the last steel plate. 4.5mm is ideal The problem with getting tied up with pack thicknesses is that different brands of slipper have differing depths to the drum. STM for instance run a thin "wearing" plate against the back, other place the first friction right onto the drum backing itself.
It does seem a bit weird as the instructions give the full stack height (all plates) of 36.5mm for the Road pack, but only the measurement of 22mm for the sintered plates in the Race pack!! I would have thought it easier to give the full stack heights for both, but that's Italians for you! As far as I can see, if you have 9 sintered plates then you have the Race pack. If you have 7 sintered plates you have the Road pack. Are they all new plates or is this a second-hand unit? Any kind of grabby-ness and screeching is usually down to the release of the clutch plates and that is mostly down to those dished plates, so I'd check your stack height first and then make sure your dished plates are ok.
I had the same issues for ages. I tried cleaning the plates, scuffing both the friction and steel plates with 400 paper, changing stack heights by 0.5mm at a time etc. In the end it was down to the clutch only having one dished plate in, I now run my clutches with 3 dished plates and they are all silky smooth with no grabbing or graunchiness.
Looks like I have installed the "racing" pack with 9 sintered plates. what thickness should these plates be - the Bucci instructions don't give the dimension of these.
I have a Bucci slipper in my tweeked 996SPS, I always keep it between 36/37mm and it's as sweet and smooth as you like. It's not with me right now to be able to tell you how many plates in what sequence i've got but Antonye seems to have the info. Oh, and don't throw any plates away, I mix and match a bunch of used plates I've got to keep the right thickness.
I have the same problem with one of my slipper clutches and I might try the extra dished plates. Am I right in saying they are thinner from memory, is it 1mm for them?
it doesn't matter how many plates you put in the important factors are 1)that you start with the correct plate for your given clutch type as a general rule slippers start with a sintered ordinary clutches start with a steel 2)you put the plates in alternating after the first plate 3) forget a stack height away from the bike just measure with a vernier that the final plate is 4-5mm below the edge of the inner drum you can adjust or optimise this using the 1.5 or 2mm steels
Once you get the stack height perfect I have found all ducati slipper clutches work better with brembo/accosato/magura etc radial clutch master cylinders. My old DP slipper was a bitch for pulling away from stationary but I found the STM slipper much better so sticking with this brand from now on.I running bronze racing sintered plates in mine which are perfect performance but wear the alloy clutch basket quicker.
Swapped a 1.5mm for 2mm and now have the optimum measurement of 4.6mm below the inner drum edge. Hopefully that will sort it. Thanks for all your help! R
of course we could confuse it all with the dished plates…how many, which way around, and so on…..:wink:
