Issues with multi plate clutches

greg brillus

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One problem that many Vin owners are finding with their multiplate clutches is they seem to drag, or else crunch into 1st gear....So why does this happen to a modern design, that does not happen on the modern bikes they were designed to fit........On the original Vincent clutch the chainwheel and clutch drum tend to wobble somewhat due mostly to play in the PD 22 and PD 24 bushes, plus perhaps some ware in the C 3 carrier. This is common and does not seem to matter too much as the primary plate only consists of one friction plate and two driven plates........However, I do wonder.... If this condition exists with an aftermarket multiplate, that this may indeed be a symptom that the muti's design struggles with. On the newer clutches, there are very fine tolerences that the plates are working with.....that is, that the plates both driving and driven are a very snug fit on the center hub and the outer basket.....If this outer basket is "Wobbling around" if you like whilst running, would this not cause the plates some grief when trying to separate..?? I am not that familiar with modern bikes, but i would think that their clutch assemblies would have little or no play in their outer baskets.......On the Vincent clutch, if the bushes in the chainwheel/ clutch drum could be retro fitted with a sealed bearing/or bearings to remove this condition, I am sure that the clutch would function much better.....Any thoughts..?? I personally prefer the original clutch, but i can see how a badly worn one would cause most owners near complete hair loss to repair, so i can see why the multi's are a fairly common retrofit................Be interested to hear your thoughts......Cheers.....Greg.
 

Howard

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I wonder how a Vincent servo clutch would work on a modern Honda.

I think it comes down to mismatching parts from various "clutch systems" - it's no use blaming the multiplate clutch if you've only got levers intended for a single plate clutch!

I use a BSA A65 clutch, it runs dry instead of in oil, and it only lifts about half the distance it would on the donor bike. Obviously a useless piece of kit, nothing to do with the guy who fitted it. :)

The fact is, when it's set up to lift squarely, and the plates have a squirt of oil on them (thanks to whoever it was that told me to do that), it's a reasonable clutch and some changes into first are very quiet. It also helps that I've spent years getting the last thou of lift possible, changing lever ratios and shortening the cable spacer.

H
 

ClassicBiker

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I made mine from a Triumph 650/750 donor using kevlar friction plates designed to run wet or dry and new steel plates. The drag I intially experienced was from using a set of steel plates I had laying around. One of our local section members is a retired drive line engineer from GM who specialized in clutches on Corvettes, who upon hearing of my problem with drag pointed out that the amount of lift might not be the issue as once pressure is off if the plate is flat and everything is free it is unlikely to drag. Sure enough the plates I thought were flat were ever so slightly warped and there were minute divets in the hub and basket. At the time I didn't much of it but new steel plates and carefully filing out the divets cured the drag. As for lift to be safe a couple of flat washers between the cable abutment and the G50 and I've got plenty. I agree with Howard that it is probably about half of the donor bike. I did all this as no matter what I did to stop the ingress of oil into the original clutch I failed miserably. New bushes, new seals, what have you. In retrospect I believe wear, where the garter seals contact the shoe carrier and the chain wheel are to blame rather than the seals themselves. Now that little bit of oil leaking in helps rather than hurts. As far as crunching when engageing first goes, it isn't any worse than my '66 Triumph which is running a belt primary and dry clutch. Which is to say if the idle is reasonbly low it is near silent. What I find though is that both the Shadow and '66 Triumph are some what abrupt compared to my '95 Triumph. The Shadow and the '66 seem to engage almost at the end of the travel of their levers whereas the '95 is far more progressive and begins to bite as soon as you start to release the clutch lever.
If I were to do anything different I would incorporate the Triumph clutch shock absorber rather than rely solely on the Vincent ESA.
Steven
 

clevtrev

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They crunch into first gear, because you have not bothered to make sure you have enough lift. Also to ensure that is is lfting the full amount.
As for the Vincent ESA, it is far too slow to operate. There is probably ninety degrees of movement, before it affects anything.
 
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greg brillus

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Thanks so far for the reply's....Obviously a common thing is the amount of lift available. With the ratio of the original clutch designed to lift only one plate, then it is always going to be a challenge. Look at the simple system that Triumph used with the ramping of three ball bearings...but also the short length of the lever and the handlebar lever ratio. No wonder they had heavy clutches. Getting back to my original comment....one thing i found was to give the friction plates a bit more clearance in the outer basket by carefully removing a small amount off each ear on every friction plate....but not too much as to cause them to rattle. This definately helped to let the plates free off from one another. As an asside, has anyone felt the hydraulic clutches on some modern bikes....sensational............Greg.
 

Martyn Goodwin

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Thanks so far for the reply's....Obviously a common thing is the amount of lift available. With the ratio of the original clutch designed to lift only one plate, then it is always going to be a challenge. Look at the simple system that Triumph used with the ramping of three ball bearings...but also the short length of the lever and the handlebar lever ratio. No wonder they had heavy clutches. Getting back to my original comment....one thing i found was to give the friction plates a bit more clearance in the outer basket by carefully removing a small amount off each ear on every friction plate....but not too much as to cause them to rattle. This definately helped to let the plates free off from one another. As an asside, has anyone felt the hydraulic clutches on some modern bikes....sensational............Greg.


I have a 2013 Moto Guzzi V7 Classic with a cable operated clutch. The clutch operation is WAY heavier than the clutch in my 62 yo Comet!

And yes - about 50% of the time the Guzzi crunches moving into 1st.

Martyn
 

Howard

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Jap bikes are made for wimps Greg. My Honda stops on a sixpence (what was that again) with 2 fingers on the lever, and the clutch can also be operated with just 2 fingers - must be all the "working out" I've been doing over the years with drum brakes and heavy old British clutches. :)

H

I've just re-read this ..... the only working out I've ever done is in the margin!!
 
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greg brillus

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Just took a 51 Shadow with a V3 clutch installed for a test ride, and seemed to work fine. I put it into 2nd gear first, then back to 1st without any crunching. This particular bike had the early and very tall 1st gear ratio....takes a little slipping to get under way, but the torque of the engine combined with that ratio is quite something else...the lamp posts start gathering together rather quickly. I note on some of your comments about the multiplate clutch causing the handlebar lever to release the clutch with the lever almost at the end of the travel. This can only be caused by the long length of the G 91 lever in the kickstart cover being so long.....which again is a ratio issue. I think it could be made to work better, but would require some other form of opperating mechanism, perhaps from another make of bike. Need to keep it tidy and functional without destroying original parts. It may be something i will look at when building up our twin racer with a Newby belt/ clutch kit............Greg.
 

BigEd

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The standard clutch, on a twin, is delightfully light so talk of heavy clutches might be attributed to non standard clutches with heavier springs, poor cable run, poor cable lubrication, non standard clutch lever with too large a pivot to cable nipple centre dimension, etc.

If you have drag because you are having difficulty getting a plate clutch to lift evenly it may be due to springs of different strength or wear or warping in the plates.
More lift will help in situations like this and this can be increased by using a clutch lever with a larger pivot to cable nipple centre, e.g. 1.125".
If we are working on a twin the Vincent Spares Company do an ET27/2 adjuster that gives slightly more lift. (The gear cover change cover has to be removed to fit this.)
Don't forget that the1.125" clutch lever and ET27/2 give more lift by altering the leverage ratio. You never get something for nothing, a little more lift is traded for a slightly heavier pull.
 
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