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My first slipper clutch, Ducabike - 1098S. Have questions

16K views 14 replies 6 participants last post by  Agr0 
1. After the first friction plate I had to install the 2mm convex plate. I put this plate on my glass table and on both sides I cannot tell for the life of me any difference in sides. The 1.5mm plate, absolutely. So I installed as usual. Any concerns with this?
Ball bearing slippers are not standard clutches, you can't use the convex plate with them as it will fall between the crack which is generated when the hub moves out to release the pressure plate.

Standard ball-bearing slippers like the Ducabike one, starts with a friction disk and then goes metal/friction all the way to the outside with the last disk being metal. The convex plate is designed for standard clutches without a metal plate on the back of the hub.

2. It came with RED, BLUE and YELLOW springs. I put the race red springs as my bike is a track bike. But it is my first slipper so I have no idea what the difference would be with the blue or yellow springs. Anyone know?
The springs keep tension on the pressure plate. They are all that keeps the pressure plate from slipping. Different spring stiffnesses (the colors) are designed to increase or decrease the slipping of the clutch. Most people do this adjustment through stack height, but having the ability to adjust spring stiffness as well is good. 4 spring clutches are not good at dealing with the power output of a 1098/1198 however, this is one reason Ducati moved back to a 6 pin clutch on their race bikes in recent years.

3. I rode it down the street got up to 4th, then slammed down to 3rd and tried 4th to 2nd. It was so different! It felt like about 1.0 to 1.25 seconds it would not jump, but just sort of hum there and smoothly be in the gear I selected. I guess this is the idea right? I used to go from 4th to 2nd at the track and not sync my RPM's perfectly and get huge wheel hop. Scared me many times. I think this is gonna help
A well setup slipper should act like that. You should be able to down shift at any speed and it should slip until the RPM's and rear wheel speed match.

4. Life span. I have to imagine that a slipper wears quicker than a regular clutch, right? When it slips, it must be wearing more?
Dry slippers have substantially greater wear then wet slippers OR on-slippers. You'll have one friction disk smack in the middle which will fail on you. So have spares at the ready on the track, so when you need it, you've got it.

5. The pull on my clutch lever is totally different. I guess this comes with any clutch right? new plates, thickness is different, etc. So where it was before, if I pulled in, I couldnt even switch gears. I had to adjust so the ASV lever was out much further. Then when I pull it in, the clutch doesnt disengage until right before max. I dont think I prefer it this drastic. I have a STM slave clylinder. Not sure of the size, 28 29 30mm? No idea the previous owner had it on the bike. I know how it is though and I would get used to it. For now it's just *different*.
Its probably the stack height which is a problem. Re-check the instructions on that convex plate, thats gonna screw things up stack height wise. The Barnett instructions are wrong, a lot of people ship those with their slippers, not realizing they're wrong.

The clutch lever will feel different, but not too different. Your slave is probably a 28-30 or something that range.
 
I see the confusion… they put the convex plate at the end of the stack where the pressure plate is. Thats a very interesting idea. But I don't know of a single slipper that comes with a convex plate. I think they're using it simply because they refuse to ship a special set of clutch plates for a slipper vs standard clutch. So they simply give instructions on where to put the plates on a slipper and a standard clutch. It won't hurt anything, but its just very strange.
 
I've learned to slowly release clutch lever, but it is something I have to do consciously.
Actually the trick is to rev-match when downshifting. Basically blipping the throttle as you downshift, to match the revs based on the output gear ratio. It takes a bit of time to learn the trick, but back before slippers were invented, thats what people were using. You see a lot of older superbike riders still use that technique today.

So I have to think about it. Im guessing with more track days I will be able to do that automatically coming into a corner... That or spend the money on a wet-slipper
Yea a well setup slipper is bloody magical. I personally think slippers should be required on race bikes, it can be too dangerous to not have one due to the rear completely locking up in certain circumstances.
 
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