My quick and dirty method of an extra clutch plate solved the immediate slippage problem and allowed me to try and start it, but obviously I needed to find a more practical solution, one that didn't involve making the bike harder to handle on track. There's no point making a bike faster with a great engine if you lose time on every corner entry.
They say "every day is a school day", with regards to learning. I can't truthfully say it's been a fun learning project, more like a Ducati-dissident re-education program where they break you down and then rebuild you with a different mindset. So it is with the clutch.
You need to forget about the Japanese (normal?) mindset where the clutch is something out of sight, out of hearing, out of mind. The only time you think about the clutch on your HonYaKaSuki1000RR is when there is an issue, right?
Contrast that with any dry clutch Ducati and the clutch is LOUD and proud, front and centre of the riding experience. It is part of the bikes signature, writ flamboyantly large. And it is a cranky piece of kit: the clutch pack thickness must measure 38mm (+/- an expletive), the slipper "spider" springs break with monotonous regularity, the slipper's require constant maintenance, during which you find yourself chasing those bloody ball bearings to the farthest reaches of your garage floor, they sound like a Salvation Army collectors convention after a few too many red cordial's etc etc. And yet many Ducati owners love 'em, as if you needed any more proof of their mechanical masochism.
All of which begs the question: why? It comes back to the same philosophy as those RS oil lines I mentioned a while back, yes it's all of the things above but it is also instantly accessible and easy/fast to work on, making it perfect for a race bike. No draining the oil, no big engine covers to remove, when kneeling beside the bike it is literally just sitting in your lap. Mechanical sympathy comes second to getting the holeshot when the clutch is this easy to work on: just remove the 4 x M4 screws to release the spring collars and access/replace the plates in a few minutes, or adjust the slipping action in a few seconds by replacing the 4 x coil springs:
All of which is well and good if you are operating at a certain level. Obviously I'm not at that level....but the engine is. What is the main point of difference between a Ducati Corse WSB clutch which would normally be fitted to this engine and an OEM or common aftermarket clutch? The answer lies in the colloquial name for a Corse racing clutch, which is termed "4 spring" vs the OEM "6 spring", for pretty obvious reasons. This is a partially disassembled Corse 4 spring clutch:
The large spider spring, bottom left, is the normal clutch spring that forces the plates together (and is almost considered a consumable, as it fatigues/breaks fairly regularly). The 4 x coil springs control the slipping action by forcing the inner hub, below:
Against the backing plate/flange:
Note the one way ramps on both the hub and flange, which are greased in normal operation (part of that maintenance regime I mentioned). So the bike drives forward as per a "normal" clutch, but on deceleration the rear wheel exerts a reverse rotational force on the clutch, so the ramps slide against each other, wedging the clutch plates apart and allowing the clutch to slip. Want more or less slip? Just fit stronger or weaker coil springs, making it harder or easier for the ramps to slide.
The above is the simple and most "bullet proof" version which required regular greasing of the ramps; later units utilised ball bearings between the ramps for less wear/maintenance, and later versions again replace the spider spring with another set of coil springs with a few more moving parts, it's added complication but eliminates the spring breakage issue.
My apologies, you are probably wondering wtf is with this deep dive into such a basic component of the bike? Check out the parts diagram below, in particular item #39, on the middle left edge and you'll see what is scratching my mechanical itch (ignore the highlighted components):
....it's a locking pin: it inserts through the front pressure plate, through the hub, into the orifice in the flange, to lock the slipping mechanism on start up. Once started you pull the clutch in, stomp on the rear brake to stop the rear wheel and therefore the clutch, pull out the pin, and away you go with a perfectly functional slipper clutch again.
In the video I posted earlier you can see one of the guys bending down at about the 50sec mark, he leans on the rear brake and then removes the pin:
Seen here in situ:
So the answer to my prayers is out there, with the Corse 4 spring clutches reasonably available. Unfortunately, even several years later, the images above are as close as I've ever got to the official locking pin, an experience mirrored by everyone else I've ever spoken to.
So my perfectly good Fast by Ferracci 6 spring slipper had to come out and be consigned to paper-weight duties. Another $1000AUD later (sigh) and a near new Corse 4 spring unit went in in it's place. This is my actual clutch, a later version (as fitted to 1098RS) without the failure prone spider spring which is replaced by the blue spring/collar arrangement at top left:
FYI, the stock road setup has a steel clutch basket and steel friction plates, but the performance/racing upgrade substitutes these with an ergal basket and aluminium plates for a nice reduction in rotating mass.
With the pin only available at the Hogwarts Ducati dealership, situated adjacent to Kings Cross Station platform 9 3/4's, I had little option but to make my own. After a bit of measuring and head scratching this is what my trusty lil' lathe turned up:
Some online discussion informed me the lower o-rings aren't really necessary but the idea of the thing self ejecting at a few thousand RPM didn't hold much appeal!
Obviously this meant cutting the centre out of my clutch cover. I could have gone for one of the vestigial carbon covers as seen above but preferred a bit more protection in the case of a crash, and realistically this cost nothing but some sweat equity and the courage to hack into a nice billet component.
With that, my not so quick and rather dirty 999RS conversion is technically complete...I think:
