Triumphrat

Rayzor61

somebody give this old "know it all" what the hell a slipper clutch is and what it does>>>> :???:

B02S4

A slipper clutch allows a bit if give on the downshift so you don't need to match the revs exactly & increases control on the downshift by preventing the rear wheel from locking due to abrubt compression braking (by failing to manually match the revs to the gearbox selection). In other words, it can save your a** & reduce the probability of a highside. On the street it's not necessary IMO, but on the track, well sure, why not.

loco

My experience with slipper clutches is limited to when I used to race radio controlled cars.
The power to weight ratio of these things is impressive, but opening up the throttle quickly especially when cornering can see you drift and lose control. In the straights it reduces the wheeling whilst also allowing the (two-stroke) engine to reach it's power band quicker (think a race start where you hold the engine in the power band and slip the clutch, keeping the power on).
A slipper clutch essentially controls the amount of torque that your engine is allowed to put through your transmission. On a bike, I would assume it lowers the chance of a wheelie and I guess could also prevent lockups if you downshift too early. It would allow you to open up earlier around a corner on a track.

I'm no motorsport engineer, however, so take what I say with a pinch of salt!

__________________
<img src = "http://www.frenchgeek.com/images/955ism3.jpg">

tcb

loco: a slipper clutch on a motorcycle only affects decelleration engagement, not accelleration. :wink:

9264

Kawasaki called it a back-torque limiter. Maybe that's more helpful? The clutch can be set up to slip on the down change, so as not to lock the rear wheel. They were fitted as standard on ZX-7R and early ZX-9R Ninjas, but required kit plates and springs to make them active.

GeoffE

Hi,

I agree with B02S4's comments.

An important aspect to consider if thinking about using a slipper clutch on the road is that there is no engine braking. With a 4-stroke engine I think engine braking is an important aspect of balancing the bike up when riding on the road - turn the throttle off and the engine helps slow the bike down, and helps keeping some of the weight at the rear & allow the front suspension to handle the bumps better. A slipper clutch does not (and neither does a 2-stroke engine) enable engine braking, and so is perhaps more suitable to race track conditions and adopting the needed different riding style?

Ciao,
Geoff
:wink:

[ This message was edited by: GeoffE on 2007-01-01 11:31 ]

9264

No engine braking with a slipper clutch? That is not correct.

The amount of slip is adjustable by the number and thickness of the clutch plates, and by the strength of the springs.

As I said above Kawasaki ZX-7Rs and early 9Rs had them fitted as standard, on the road-going models. They are fitted with thick enough plates, and strong enough springs, so that they don't slip.

9264

http://homepage.ntlworld.com/webzxr/...perclutch.html

And here is a web page all about them.

GeoffE

Hi Martin,

Apologies as I missed the relevance of your earlier post - I agree, they can be adjustable.

That is an interesting link you posted. Thanks.

Another link that may be of interest is the Sigma site, and there is a brief write-up on the history: Sigma

Ciao,
Geoff
:wink: