Thanks for finding that Andy. It appears he reduced his stack height to 39mm by playing around with the thickness of the drive plates. As my old friction plates were down to the 2.6mm minimum and there are 8 of them, when replacing them with the new* I've increased the overall height by 3.2mm. I've 40.5mm arithmetically, 41.1mm as measured with the callipers (see photo above). Therefore before the swap I must have had 37.3mm and all was fine (albeit it was very rattly but that's due to the worn clutch basket and worn tangs on the old friction plates - it's now very quiet). Thus, if I were to remove one drive plate of 1.5mm that may cure the issue @andyb can I put 2 frictions together as that's what will happen if I remove a drive plate? ps @Chris the plates came from Newfren.
identify one of the steel plates with a dimple or dot on it ....you can check it to see its dished on a flat surface/ put two 2mm first then alternate friction ,steel, friction, steel, friction, dished plate, friction, ... and so on up to 36.5 finishing on a steel ... build that in to the hub two seems in first. see where its at then...
if you need more room to get an other friction and steel in you can change one of the bottom 2mm for a 1.5.. if you need to increase a bit more then after finishing on a steel place another thin steel on top of that then the pressure plate... just to confirm your pressure plate has teeth on it.....
no i wouldn't put two frictions against one another and there is no need! Start with the two steel .... and finish with a steel or if needs be add a second steel before the pressure plate.
So the stack height on a std clutch isnt as critical as a slipper....there is a bigger ball park for it to work in...
If no joy after Andy's suggestion then as long as you are still getting adequate pushrod travel, and you've ruled out that even by replicating low stack height (when at least it worked ok), then could just be bedding-in needed with initially "sticky" plates (and even possibly well-fitting tangs in new drum). You reminded me that a Ducati mate rang scratching his head with same dilemma on a 996 and this was also with new Newfren friction plates, and his bedded in after 40-odd traffic related miles - i.e. good clutch "exercise". To save gearbox from cold (with this problem) i always select a gear and with clutch pulled in, walk the bike about and hopefully the dragging improves enough to then start bike without the sickening noise and forward lurch as you select a gear "conventionally".
All good now . Thank you very much @andyb and everyone else who contributed, very much appreciated. Yes, AndyB, the pressure plate has teeth. I stripped all the plates out again and carefully checked each of the 1.5mm plates to see if one is dished. It’s not obvious, it’s not marked with a dot or anything, it’s not mentioned in the workshop manual, but one is very slightly different in as much as the teeth have a bronze coloured edge to them (see below). Using the other drive plates as the flat surface and placing this one plate on top it’s barely noticeable that when one way up the outer circumference sits flush with the plate below but when flipped over the outer circumference sits a fraction of a mm proud of the plate below. Having checked the other thin plates non of the others exhibited this slight dishing. I replaced the plates as per AndyB’s suggestion above and placed the dished one in the middle of the stack with the concave side facing outwards; it’s 50/50 as to which way I placed and I’ve no idea if it matters but perhaps I guessed luckily. I put the pressure plate back on, started her up and all’s good. No more clunky gear selection, no clutch drag at all (at least no rear wheel movement when in gear, on the paddock stand, and clutch disengaged) and it’s easy to select neutral again. I’m a happy chap now, thanks fellas.
Yeah, just done it. Getting the plates out is the fiddly bit even with my ridiculously expensive Ducati Special Tool . Oh, and writing the post above on here takes time.
You could use a "magnet on a telescopic stick" next time Paul maybe?, although above method is therapeutic/fun - were you any good at hooking them ducks at the fairground?
Think I missed something along the way.... What was different about your ok plates stack compared with the first incarnation?
I really don’t know. I was careful when disassembling to keep them all in the same order. The only thing I can think is that when I was reassembling originally, the other week, I know I dropped a couple of the drive plates, perhaps I picked them up and put them back in the wrong order. Perhaps one of them was the dished plate
Did you measure stack height....not that its too critical 36-38 as the teeth on the pressure plate engage on the inner hub so spin around same as the outer steels so in theory if you could fit them in you could put 10 in there..... Once you have the stack built up to around the 36-38 then you can ply with the thickness of that steel against the pressure plate for feel and grip. the dished plate ... consider this as an extra spring to help with the clutch engaging.... you can have 2 even 4.....both my slippers have 4..
When I reassembled it all I thought Id start with all plates and the full stack height ie 40.5mm (I presume I could measure 41.1mm due to the dishing of that one plate which wouldn’t be discernible when that plate’s thickness is measured alone). My logic was, that’s what came out, ie what went in at the factory (I don’t believe any of the clutch had been replaced before; the bike’s done 30,000km) and it all fitted and worked before; if it doesn’t work I’ll start removing plates to reduce the stack until it does work. As it happened it worked, so all’s good. We are talking fractions of a mm difference here though. I checked how far the plates moved out when the clutch lever was pulled before I re-jigged the plates and then checked after wards, albeit this was a purely visual check as to where the friction plate tang sits against the clutch basket. Easy enough to see as the clutch basket was new and riding it the other day for the first time had caused the red anodising to be removed where the tangs move. The pictures below show the minimal difference in movement. Minimal yet enough to stop it dragging. Once again thanks for your help ps I had heard/read about some clutch packs having a concave disk but as there a) was not an obvious one in my pack and b) the Ducati workshop manual makes no mention of it, I assumed there wasn’t one in my bike.
