Pukka Slipper Clutch

[blow_away]

Once again I turn to the PB massive for light in my tunnel of darkness.

Who is running a pukka slipper clutch? How effective are they? Worth the extra money over the standard slipper?

The bike is a 2007 4C8 Yamaha R1 being used for racing. The clutch was getting grabby, so I whipped it out yesterday (steady now) and the outer basket is quite notchy. So I'm going to file down the notches and keep it as a spare. So the questions are;

1. Is it worth getting the ally outer basket hard anodised to minimise wear, or is this a waste of time? Bear in mind that the big drive gear is rivetted onto this basket, so I'll have to dismantle all this, get some new rivets made up and possibly need a grown up help me reassemble it all. I haven't priced up a new basket from Yamaha yet, but I don't expect it will be cheap.

2. A Sigma clutch is £565 + VAT = £678

http://www.sigmaperformance.com/slipperclutchrange.html

3. A STM clutch is "the world's finest clutch" according to their website. £848.82.

http://www.smr-performance.co.uk/shop/index.php?route=product/product&manufacturer_id=32&product_id=139

I realise I need a new plate pack as well, so this is going to be £800 ~ £1000 or so I guess by the time I've bought those. I believe genuine Yam plates are the best option in this case?

http://parts.yamaha-motor.co.uk/ypec_b2c/

Note parts 12 (plate seat), 13 (spring, clutch boss) and 23 in the above link. When I dismantled the clutch parts 12 and 13 were missing completely, and I only have 2 of the three slipper springs part 23. Now I think that a previous owner may have deliberately left out part 23 in order to get the slipper clutch slip more easily? Is this right and/or a recognised modification for these? I can't see why 12 and 13 would be missing though.

This is going to be a big hit in the race budget for us, whichever way it goes. So any useful advice will be gratefully received.

[Gmanb1h]

I have a sigma slipper on my zx6r. Can't go back to normal clutch after sliding it in with no chatter or upsetting the bike

[2moto]

I wouldn't bother anodising the reconditioned basket. Anodising doesn't really help with the hammering of the plate tongs against the basket. Hard anodising mostly helps reducing wear on sliding joints.

[lorenzo]

While I agree in principle with what you're saying Mike, isn't it the case that one less thing to do will help the rider concentrate on other things a bit better? For all the bullshit around Keith Code, his $10 of concentration theory is pretty valid; why spend $3 on clutch control mid corner when you could be spending a bit more on throttle, hitting apexes, giving your rival evil glances etc.

[MonkeyJim]

<diatribe snipped>

I'm sure that mike makes a valid point in there somewhere. and if you're a great rider / racer you can feather the clutch as necessary, as you back it in to the apex on the perfect line.

ahem.

but for me, on a trackday (just a mere mortal, not a Racing God) having to feather the clutch would be one more thing for me to think about / do.

whereas with a slipper clutch it's all done for you, automatically. For me, that's a no-brainer (and I hate that expression)

I had a sigma one in my R1. it was utterly superb and I couldn't fault it in any way. first time I'd tried one and for fast road or track use I wouldn't be without one.

it fitted straight into the OEM clutch basket and used the standard frictions, steels, spring etc. worked perfectly out of the box.

can't comment on the other makes as I haven't tried them. But one of my reasons for buying the k6 was it came with a slipper clutch.

the OE suzuki one isn't quite as nice as the sigma one, but it's good enough and better than not having one. or feathering the clutch.

[Barry]

Last year I had a stock blade clutch and as milemilee points out, I did try and slip it 'by hand' when going into a corner, but I found I was concentrating too much on this and not enough on getting a good entry into the conrner, and going in a lot slow than I should/could! And I was losing a lot of places braking into corners because of it.

I fitted a Sigma over the winter and although I've only managed 2 'half' races so far this season, the difference is unbelievable. Mainly in that I no longer need to worry about getting the slip right as I approach and enter a corner and I can no concentrate more on getting in quicker and hitting the apex. So the slipper for me just eliminates the need to worry about what the back is going to do as I turn in, I now 'know' what its going to do. And for someone who has only been racing just over a year, it's a massive benefit.

Now I just need to get the bastard to stop running wide on exit when I'm on the power!

[blur1]

Had an STM slipper in my R1 longer than anyone i know.

Brilliant in all aspects.

[Superdunc]

I've used the method Mille described, and it soon becomes programmed into the Cerebellum, and doesn't take any concious effort. I do find you can shift down the gears a little more quickly with a slipper, though it's not really an advantage.

Al, is corner entry an area where Andy is struggling particularly? I personally think your money would be better spent on a new clutch basket, tyres, and cider.

[porter_jamie]

you have to use the method described with the mono, or you find the lower fairing fills with oil quite quickly. closely followed by bits of conrod.

after racing a stroker where you just bash the lever down loads at the end of the straight it does take a bit of concentration. a couple of lads fitted them to monos and said they prefered it and allowed them to just slam down the box and concentrate on something else. never tried one myself. i think the 690 motor we have has one so we will find out.

[blow_away]

Andy is a demon on the brakes, as most of you know

Whilst I accept MM points above, I would prefer to just put a slipper clutch in and give Andy one less thing to think about. A good workman with a better tool will become a better workman IMO. We are racing with Hottrax, you are talking about 8 lap sprint races rather than long hauls, so there simply isn't much time to stalk, plan and pass, it needs to be stick it up the inside and FO into the distance sharpish.

The thought was prompted by the second hand availability of these units. Kit Parts recently sold an STM slipper assembly (albeit for an earlier model) complete with plates for £300, which would cost me less than buying new Yamaha parts. Thus the cider budget would remain relatively unmolested.

[theo]

Having been used to inline 4s, I found the severity of engine breaking on the twin/single to be quite marked.

I would prefer a slipper clutch so I could just bang it down a couple of gears and release the clutch as fast as possible. One less thing to be concentrating/thinking about when my little brain already has enough to think about with breaking points/lines/posing for photos.

Luckily for my budget, the class doesnt allow them so stuck with a normal clutch I am.

[Superdunc]

Al. slippers do need a lot of servicing. I would be warry of second hand units, no matter what the provenance, to get them working as intended, they will probably need a few quid spending on them.

They are also harsh on plates. Pro teams will have the stack out nearly every session to check wear, and replace the plates frequently. If you don't maintain the stack height within very close tolerances, the point and amount the clutch slips will change, making the bike less predictable.

[2moto]

@millemille - tongs. LOL!

[Superdunc]

Is that true of all types? I knew it was the case with the basic jobbies in ZXRs, but I was of the understanding that modern jobbies weren't susceptible to changes plate/stack thickness (within reason).

Rich

Certainly the case with the Suter on my SXV, and the ex Crescent BSB bikes I know people who have run. Not so much of an issue if you only use the bike for a run to the seaside on sunny sundays. But if you're using the bike hard on a track and working the slipper then you need to be on top of them.

[MonkeyJim]

Is that true of all types? I knew it was the case with the basic jobbies in ZXRs, but I was of the understanding that modern jobbies weren't susceptible to changes plate/stack thickness (within reason).

Rich

wasn't the case with the Sigma one in my R1.

did god knows how many trackdays and countless thousand hard road miles including laps of the Ring.

it never required any adjustment and I can't say I noticed any wear to the clutch plates above what you'd normally expect

the current owner of the R1 is a mate and he's not had any issues with it either, though he takes it a bit easier than me.

PS and I bought the unit second hand off ebay, albeit I had dealt with the guy a couple of times before and knew him to be genuine and he only sells quality bits. Paid £300 IIRC, though that was some years ago

[blur1]

Yep. Same here. No plate wear issues after numerous track days etc etc etc.

[thefatman]

Are you guys not suffering wear dropping straight down 3 or 4 gears and letting the clutch straight out again? I wonder if this makes a difference to wear.

[Farmfab01]

MM is of course right in theory, & slipper clutch does seem an expensive item, but compared to a major engine blow up or a couple of big crashes while learning the correct clutch control technique, a slipper clutch may seem cheap comparatively, (& hurts less too) its nice to have a safety net when the unexpected happens to us hobbyists.

[blow_away]

I think SuperDunc is right. We are noticing a significant amount of clutch wear, the friction plates were on maximum wear limit before three days at Cartagena (well five really as we shared the bike, but I'm a lot less harsh on the clutch than Andy). Now after one track day and two races at Oulton (so about fifty laps or so) the plates are below minimum unit.

My opinion is that the race starts really hurt the clutch. Apparently the guys running BMW are getting three race starts per clutch Still, I suppose its the price you pay for the big power those things put out.

Blur, got any info on the missing slipper spring?

[theo]

I think SuperDunc is right. We are noticing a significant amount of clutch wear, the friction plates were on maximum wear limit before three days at Cartagena

Have you tried media blasting the metallic plates? This may or may not accelerate the wear.....

[blur1]

I think SuperDunc is right. We are noticing a significant amount of clutch wear, the friction plates were on maximum wear limit before three days at Cartagena (well five really as we shared the bike, but I'm a lot less harsh on the clutch than Andy). Now after one track day and two races at Oulton (so about fifty laps or so) the plates are below minimum unit.

My opinion is that the race starts really hurt the clutch. Apparently the guys running BMW are getting three race starts per clutch Still, I suppose its the price you pay for the big power those things put out.

Blur, got any info on the missing slipper spring?

Missing slipper spring?

[Farmfab01]

if you're revving the enngine rhard enough on the overrun to be near the limiter you're chaning down waaaaaay too early.....

Accelerating up through the gears my old jelly mould CBR 600 had a nasty habit of jumping back down a gear (they were known for having a weak gear box when raced) A slipper clutch would have I presume worked instantly, where whipping in the clutch by hand left the motor screaming for a fraction of a second - just my opinion though as I’ve never actually used a slipper clutch & I always did it the old fashioned way

[MonkeyJim]

Accelerating up through the gears my old jelly mould CBR 600 had a nasty habit of jumping back down a gear (they were known for having a weak gear box when raced) A slipper clutch would have I presume worked instantly, where whipping in the clutch by hand left the motor screaming for a fraction of a second - just my opinion though as I’ve never actually used a slipper clutch & I always did it the old fashioned way

Mike's correct.

that's what the rev limiter is for. but a rev limiter only works when the engine is driving the wheel.

on the over-run the rev-limiter doesn't work, another reason why a slipper clutch is a good thing.

[Farmfab01]

Nope. Slipper clutch only works when the rear wheel is trying to driving the engine

Mike's correct.

that's what the rev limiter is for. but a rev limiter only works when the engine is driving the wheel.

on the over-run the rev-limiter doesn't work, another reason why a slipper clutch is a good thing.

That was exactly my point, it used to jump (for example) from 4th to 3rd & take the engine past max revs in 3rd as it had gained a certain amount of road speed in 4th before it jumped down, & the extra speed drove the rear wheel & over revved the motor, which I believe in theory a slipper would have protected against, I tried various things like switching from a road shift to a reverse/race shift lever which helped a little but didn't fix it, I seem to remember I was told the best way to sort it was to cut the dogs on the gears

[blow_away]

Missing slipper spring?

Sorry B, not making myself clear, this bit of post #1

http://parts.yamaha-...co.uk/ypec_b2c/

Note parts 12 (plate seat), 13 (spring, clutch boss) and 23 in the above link. When I dismantled the clutch parts 12 and 13 were missing completely, and I only have 2 of the three slipper springs part 23. Now I think that a previous owner may have deliberately left out part 23 in order to get the slipper clutch slip more easily? Is this right and/or a recognised modification for these? I can't see why 12 and 13 would be missing though.

[blow_away]

OK, sorry Blur I posted an invalid link. Trying to correct it now.

[blow_away]

Can't make the link work, arse

If you can be bothered Blur, go to the link below and pick out 2007 R1 from the options shown, hopefully then you will be able to see what I'm on about, cheers.

http://www.yamaha-motor.eu/uk/information/parts-catalogue.aspx

[blur1]

I tried looking at the site but it's a maze of getting lost trying to find the slipper clutch.

From what i understand about your year 2007, they can adjust slip tension with the springs or lack thereof.

Mine is a 1998 R1 and uses a totally different spring setup.

Infact the 1998 R1 STM slipper clutch uses only one diaphragm spring.

[blow_away]

Thanks Blur.

Just had the quote back from Fowlers, it's £778 for everything (OEM parts). Not as bad as I was fearing and I'm pretty sure I can make some savings on the bill.

[blur1]

Thanks Blur.

Just had the quote back from Fowlers, it's £778 for everything (OEM parts). Not as bad as I was fearing and I'm pretty sure I can make some savings on the bill.

Try Ronayres or Mrcycles in America for pretty cheap o.e.m prices.

Also, consider an aftermarket stm slipper.

They really are the best out there.