Slipper Clutches, enlighten me.

[LAW]

Apparently my '91 ZXR750 Tracky has an adjustible "ramp-type" slipper clutch. I know this means that some engine braking is limited by clutch slip but how does it work,what are it's limits and how do I "use" it?

Cheers guys :ayyy:


LAW

[Turtle]

Right when your wheel is about to lock up, it doesn't ........is that enough for you ?

[SLAC]

I believe its called your left index finger.. I think LOL.. You tube doohan he did it

[Cedric]

You have to put thinner clutch plates in it to actuate the slipper clutch mechanism. Download the 7R racing manual for more info - I used to think my 7R would work the slipper clutch screaming into T2 but apparently it requires some work to function properly and doesn't come from the factory in slipper clutch spec..

Though I am talking about 7R spec.. Not entirely sure about ZXR7s

[sbutler]

Less rear brake & wash off more speed before smashing it down gears, will always work better than a slipper clutch. Smooth out corner approch & entry eg: braking & downshifting, will negate the need for a slipper.IMO

[LAW]

Yeah, I've lived this long without it but it sounds kind of cool. I'm sort of more intrigued as to how they get it to slip without a "ratcheting" sound than actually relying on it.

I found an article specific to my bike and I have to buy a combination of plates that add up to .5mm slimmer than stock (or thereabouts) to take the slack out of the pressure springs. I don't think my riding is up to that level yet and I won't bother but if someone has a "howstuffworks" or something that explains it better than "Because it does."

[Cedric]

I found an article specific to my bike and I have to buy a combination of plates that add up to .5mm slimmer than stock (or thereabouts) to take the slack out of the pressure springs.

Yeah that's the one. Never had any probs with the rear hopping on the 7R but that's probably due to my lack of skill than anything else.. Top bike, the ZXR750.

[Johnny]

Blip between down shifts to match rpm and you wont even need one. Only time you will need one is if you knock down from 5th to 1st or 2nd ina hurry, in which case they momentarily lock up till it kicks in and slips anyway, so.
K6 had one, R1 has one, have never trusted them and old habits (blipping throttle on downshift) die hard..

[Kat00]

Yeah, they are unreal, Ive been on the stop in 5th at the 100mtr maker at the creek and banged it into 4th because of traffic, not an issue.......Think about that......around 10000RPM at pace and bang it down a gear.....lock the back wheel up because of compression at that speed and it ends in tears......It limits the torque so reduces the likelyhood of rear wheel lock up, sure, blipping assists but the slipper saves a bit of time.

[LAW]

Yeah, my neighbours know I like to 'blip' too :D

[Big Lunt]

Last weekends ride day I am now using the clutch to control the rear wheel lock up and actually make it slide a little - mainly T2 and T9.

I am wondering if I am going to cook the clutch now by doing that - any thoughts from anyone????

Slipper clutch are great - my zx10r has it and i luv it - almost thinking of getting it for the R1 tracky

Sorry all the blipping in the world wont help if you are coming in hard and brake late

[*Oggy*]

Law

Your thinking of the ramps as a ratchet which isnt correct.

Clutch plates are held "locked together" by virtue of (normally 6 large compression springs) clamping them together. When you pull in your clutch lever, all you are doing is using mechanical advantage to push against the force of the springs to let the plates slip against each other (ie dis-engage the clutch).

Slipper clutches with the ramp style work by replacing the single inner basket with a two piece design that are located on a set of ramps (normally some ball bearings in there to aid the effect).

Now if you go along and (for instance) go down two gears..... as the back wheel tries to slow down quicker then the engine can cope, the reverse load is transmitted to the inner basket and the two piece inner basket moves on the ramps and thus becomes longer..... which has the same effect as pushing against the 6 springs force and thus cluth will slip...

Tried to put this in lay-mans terms... hope you can visualise it.....

[Irish]

I set my (now Stetto's) 7R cluch up as a slipper and it is good!! As Cedric says get the race kit manual and it has part numbers for steel plate thicknesses.
You also need race kit springs to compensate for the smaller clutch pack. This gives extra clearance for the clutch pack so it can ride up the ramps...... my clutch was f#cked so needed replacement anyway and probaly only cost $80 extra? for race kit parts which were in stock Syd.

http://homepage.ntlworld.com/webzxr/zxr750r/Features/slipperclutch.html

[Cedric]

Last weekends ride day I am now using the clutch to control the rear wheel lock up and actually make it slide a little - mainly T2 and T9.

I am wondering if I am going to cook the clutch now by doing that - any thoughts from anyone????

Slipper clutch are great - my zx10r has it and i luv it - almost thinking of getting it for the R1 tracky

Sorry all the blipping in the world wont help if you are coming in hard and brake late

Big Lunt, you're a faster rider than I'll ever be and I reckon you'll cook the clutch that way..

[Cedric]

I set my (now Stetto's) 7R cluch up as a slipper and it is good!! As Cedric says get the race kit manual and it has part numbers for steel plate thicknesses.
You also need race kit springs to compensate for the smaller clutch pack. This gives extra clearance for the clutch pack so it can ride up the ramps...... my clutch was f#cked so needed replacement anyway and probaly only cost $80 extra? for race kit parts which were in stock Syd.

http://homepage.ntlworld.com/webzxr/zxr750r/Features/slipperclutch.html

So you noticed an improvement on the 7R then Irish? I was to-ing and fro-ing about replacing my clutch (which is definitely slipping anyway)

[Big Lunt]

Yeah I thought that may be the case Cedric thanks for confirming - all that ass end hopping into the turn does throw me off a little!!!

But will it really cook it that much for only 2 corners per lap?

[Cedric]

Clutches are a pretty hardy item though so if you can modulate the clutch to stop the hop and still get a little slide into 2 and 9 then more power to you mate! Only 2 turns out of 12 so I wouldn't worry about it too much. I still think you'll be burning the clutch up faster than normal but surely that's the cost of fast laps of the creek...

Having said that, the slipper clutch would make things easier for you I reckon

[Big Lunt]

Might scope out comparison of sets of clutch plates vs slipper clutch installation

Big Dog got it for his gixxer and it was pretty $$$$

Well she has done about 7500kms worth of track days in the past 5 years and clutch is still good - never really adjusted it either

[Cedric]

On the ZX it was a pretty easy finance decision as it cost relatively the same to do it to activate the slipper clutch as to re-do the clutch plates normally. If it's going to cost you a fair bit more to do the same and you're doing ok on your own plates though I reckon you should keep doing as you are with the same lap times until just before something fails..

My 2 bob anyway

[Irish]

So you noticed an improvement on the 7R then Irish? I was to-ing and fro-ing about replacing my clutch (which is definitely slipping anyway)

Yeah mine was slipping down the straight at EC before replecement. New clutch gave nice positive drive plus slipper worked well. First day out was Wakefield Pk and I really noticed the slipper working there. I'm slow compared to you so I reckon you would find big benefits. I went with the white coded clutch spring combo...

Clutch replacement is not hard. Just get your hands on a tourque wrench to tension everything up right again and don't forget to buy an new gasket for the clutch cover.

I can dig out the link to a free factory manual if you don't have already. Need to fiind that for stetto anyway.

[Turtle]

I think the worst place at the Creek was coming down into turn 9.....i used to "Lock Up" all the time...with the slipper clutch it never locks up anymore.....

[stetto]

I think the worst place at the Creek was coming down into turn 9.....i used to "Lock Up" all the time...with the slipper clutch it never locks up anymore.....

I found that too under hard late breaking into 9, less weight on the rear too cause its downhill probs doesnt help. I'll see how the 7r goes with its slipper

[Cedric]

Yeah mine was slipping down the straight at EC before replecement. New clutch gave nice positive drive plus slipper worked well. First day out was Wakefield Pk and I really noticed the slipper working there. I'm slow compared to you so I reckon you would find big benefits. I went with the white coded clutch spring combo...

Clutch replacement is not hard. Just get your hands on a tourque wrench to tension everything up right again and don't forget to buy an new gasket for the clutch cover.

I can dig out the link to a free factory manual if you don't have already. Need to fiind that for stetto anyway.

Cheers Irish - I have downloaded the racing kit manual and have the service manual so it's all good. I'm sinking my coin into suspension on the new 636R so I'd look at doing it to that rather than ol faithful..

[Turtle]

I found that too under hard late breaking into 9, less weight on the rear too cause its downhill probs doesnt help. I'll see how the 7r goes with its slipper

Mate it will be a different bike.........no more lock-ups

[Cedric]

I found that too under hard late breaking into 9, less weight on the rear too cause its downhill probs doesnt help. I'll see how the 7r goes with its slipper

Going to be better heading into the corner, but still a difficult turn, you got to stop the thing before you can turn it because it's too damn heavy.. Def my worst corner at EC on the 7R...