While watching the GP yesterday, my friends and I started talking about slipper clutches. We're all 2 stroke riders, so we're not really up on the subject. I thought Suzuki did the first development of them, on their superbikes, and then they caught on in the new MotoGP machines. My friends were saying that they'd been around in WSB for a longer time than that, but I don't remember hearing about it if they were. Can someone give a little history lesson on these things? Also, what WSB machines are now using them, and which are not?
I know honda went to it after they fried the clutch on the big V4 1000 that they built to win daytona.. Duct also started them on the 888...
I wonder if they had a bunch of problems and went back to the drawing board for a while, because an RC30 doesn't have one. Or so I thought anyway.
clutch Isnt it that it allows you to downshift at high speeds and avoid the wheel hopping that we all get? thats also why they said you can only get about 4 good starts outof them before they are toast. They were talking about them on speedvision during the multiple restarts at the VIR races when everyone and their brother were wrecking at the last race.
Kawasaki ZX7 has their version which they call a back torque limiter, I'm not sure if this is considered a true slipper clutch but it acts like one. I'm not sure when Kaw introduced it but my '94 ZX7 had it. When I got my current bike, '01 GSX-R600, I had some trouble (rear tire hopping) on downshifts before going into corners. I think I'm over it now.
Honda used it on one of their cruisers (shadow) back in the late 80's. I'm sure they worked the technology out w/ their superbike program before that.
In 1983 Honda debuted the FWS1000, the Water Buffalo, at Daytona. Their biggest pure motorcycle racing engine ever it was a four-stroke V four prototype designed purely to win Daytona. It failed because the trick new idea to eliminate rear heel hop wore out the clutch, an inauspicious start, but the anti hop 'slipper' clutch was born. The FWS did not come back but it had brought with it ideas that would not go away. The same year these clutches were also used on Honda's 750 Interceptor factory Superbikes. Rob Muzzy had several different versions to get his Kawasaki Superbikes into corners easily and at one time during his US racing period it's said that Muzzy supplied a drawing of such a clutch to Yamaha to keep them in the game (This one is a little difficult to verify though). It became apparent that while a slipper clutch was handy on a four-cylinder bike it was absolutely crucial to have one on a big twin. Development has continued and now no self-respecting four stroke race bike, be it superbike or MotoGP bike would attempt to race without something to stop the engine pulsing forces being fed into the rear suspension. There are several types of slipper clutch but the Ducati version is one of the simplest. The Ducati clutch is a purely mechanical device, when the throttle is closed and the rear wheel starts to turn over the engine a simple system of 45 degree ramps (with or without ball bearings, depending on budget and manufacturer) inside the central drum forces the drum up against the outer pressure plate, so forcing the clutch plates apart. As soon as the clutch starts to slip the forces holding the clutch apart are controlled and the clutch is held in a perfect slipping situation, just as you would achieve if you held your car stopped at the lights on a hill just by riding the clutch. In a normal driving situation the clutch operates just like any other. The point at which, the clutch releases (and the violence with which it does it) and the level of drag designed into the clutch make a real difference to the way the engine braking affects handling and the suspension set-up required as a result. It can be no coincidence that every racer developing a new racebike (especially the ex two stroke guys getting used to their new GP four strokes) is quoted as saying that the initial set-up depends on the correct adjustment of the slipper clutch. The need to tailor the machine set-up to the riders in MotoGP is leading to new heights of sophistication with Yamaha rumoured to be trying out a new electronically controlled slipper clutch on the M1. I am sure Honda is not far behind.
So it sounds like Ducati had it on there back during Foggy's championships? Did it just never get mentioned back then because it wasn't causing problems? Seems like it's often a topic of conversation these days, and if someone's slipper clutch isn't working properly, their chances of doing well are severely diminished. I guess it's more than just a nice-to-have item from here on...
I have a slipper clutch on my new bike and it has to be redone after each run. My bike probably has more hp than the others referred to in this thread and would hole shot all of them. It’s does 0 to 100 mph in 1.1 seconds, 150 mph at the 1/8 mile and 190 in the ¼. It’s also a heavy drinker of Nitromethane. One thing though. It doesn’t turn very well. Maybe it’s the 12 inch wide slick? You point, shoot and hold on or
The aprilia 1000cc twins have a slipper clutch. I rode one for more than 10,000 miles and never had a launching problem. I could downshift with no fear of locking up or hopping the back wheel. It was a big adjustment going to a SV that doesn't have one...
Yep, that pretty much clears up your turning problems..... that and even trying to turn at those speeds
The Aprilia's use a hydraulic/vacum actuated clutch, or so it has been explained to me. It is not a true slipper clutch but does act like one.
