C: Clutch Twin clutch . centralizing plunger.

john998

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In a drawing of the twin clutch posted on this forum it appears that the centralizing plungers C11/1 are shown in contact with the both C14 pins. Is this correct?
In my experience there is always some clearance that allows C13 a few degrees of rotation either way before any contact.
John Stainton.
 

stu spalding

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Hi John, the plungers should be just touching the pins. If the pins are worn they can be swapped around in the plate carrier C13. If you've still got clearance the collar on the end of the plunger can be undercut providing the plunger isn't hardened. (some are). Cheers, Stu.
 

john998

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Thanks for that Bill, have already made up some longer plungers and have used your single spring. Now all we need is to see the back of winter. Keep safe.
John.
 

stu spalding

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An alternative idea on why the primary plates C21 & C23 are slightly dished is that they flatten under spring pressure and thus do not need to be ground flat, in fact this may even be detrimental. None of the clutches that I've rebuilt have required this step and have worked fine. Cheers, Stu.
 

john998

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In 55 years of Vincent clutches (50 heaven, 5 years hell) the problem has never been the primary clutch. The servo clutch has worked for me for touring, road racing, hill climbing and sprinting and pulling side cars on occasions with a trailer.
As far as I can remember all the ones I have worked on had several degrees of movement between the plungers C11/1 and the pin C14. On looking through my used clutch bits I found one C11 that was a tenth of an inch longer than all the others. Have made up some of this length plungers that now are in contact with C14.
As soon as the weather improves I will find out if this is an improvement.
Having said all that if you clutch is working reasonably don't fiddle with it they seem to take a long time to settle back in. John
 

Cyborg

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An alternative idea on why the primary plates C21 & C23 are slightly dished is that they flatten under spring pressure and thus do not need to be ground flat, in fact this may even be detrimental. None of the clutches that I've rebuilt have required this step and have worked fine. Cheers, Stu.
I’m just in the middle of sorting out all the pieces to assemble a clutch. The C23 is very slightly dished and don’t really see that being an issue. In the long run, I’m not sure how much taper would be taken up by the springs (but just guessing). I figure the C24 friction plate would eventually just bed in to the taper. At this point I have only eyeballed it with a straight edge, but the taper doesn’t seem to be consistent all the way around which could be a problem. Will have a better idea once it’s checked with a dial indicator. What is a problem.... I chucked the C21 in the lathe just to clean the crud off and noticed it has way too much runout. Didn’t bother measuring it... just tossed it in the yard art bin.

John. I had added C11/1 to the list of things to buy. For some reason it never dawned on me to make them. What material did you use? Thinking I could use stainless because that’s what I have on hand?? Any advice would be appreciated.

Did I read somewhere about leaving the PD27 springs out and just using the OP11?

Now I’ll go search for that clutch drawing.
 

john998

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Hello, I used stainless as it should work harden. As for the springs see Stu Spauldings recent contributions.
Hope you have a good Christmas. John.
 

Cyborg

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Thanks Stu,
I had a look on the spares site, but don’t see them listed. Do you have Derek Sayer’s contact info? Although.... it would be nice to be able to get them from the spares co though. Have to order some stuff from there anyway.

While I’m here... what was the reason that they changed the shape of the C10 toggles. The new ones have a square end. Was that just to simplify manufacturing? Is there a reason I shouldn’t use these. I picked out the best two.
3EF49014-737C-4492-8CDF-5D810DD82454.jpeg
 
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