Registered Forum User
Mille
Posts: 150
Join Date: Jun 2002
Location: Edinburgh, Scotland
Mood: Pensive
Ducati Corse Slipper Clutch - Anyone else had experience?
Dear All
I've recently changed my racing Mille for a 998S, just like my road bike. The last time I raced a Ducati, it was a 916BP (wouldn't pull the skin off a rice pudding) and I fitted a Casoli Slipper Clutch, which I believe is a copy of the Ducati Corse one. The unit fitted and worked perfectly from the off (with standard springs and plates) and slipped beautifully.
This time around, I managed to get my hands on a genuine DP Slipper, complete with ceramic plates and harder (red-painted) springs.
My problems started when I fitted it. After getting instructions directly from Ducati UK, I found that the clutch lever would only move about 1/3 of its full travel. I realised this was because the slave cylinder was reaching the full extent of it's travel (i.e. the pressure plate wasn't pushing back sufficiently against the actuation rod.
A call to the previous owner led him to sharing his theories:
1. My assertion regarding the actuation rod was true
2. He believed that the springs were getting coil bound (the spring materials were pushing against themselves).
His suggestions were (based on past experience):
1. Place a 1.5mm washer between the control pin and the bearing, in order to push-back against the push rod.
2. Place two 1mm washers between the posts on the drum and the spring collets, in order to reduce the preload on the springs.
I took these steps on at a time. With the former, the lever movement improved, but there was still about 1/3 of unused travel at the end of the stroke. On the latter, I decided to go with one 1mm washer for the latter, in order to reduce the prospect of clutch slip.
When I tried out this setup at Croft on Friday, I found the following symptoms:
1. There is a nasty "graunching" sound when first pulling away, that begins when the clutch starts to bite and stops when it fully engages
2. Whilst the clutch does slip on downchanges, it feels positively agricultural compared to the Casoli "replica" I used to have
3. The clutch lever is still stopping around 3mm away from the bar, suggesting that the slave cylinder is still reaching its full extent
4. The sound from the clutch changes between being off and on the power
All in all, I'm feeling a little bit uneasy about this lot. How come a genuine Ducati article seems to need so much more setup than a copy, and why is it necessary to do all this shimming with washers?
I'm aware that a key difference this time is ceramic plates and harder springs, but if anyone would be good enough to share their own experiences with this unit, or their thougts on the above symptoms, I'd be very grateful.