C: Clutch Refreshing Vincent Twin Clutch seals and pieces

greg brillus

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There are definitely some area's of the clutch that should have the slightest amount of lubrication, especially anti-seize, the bushes and so on should not be set up so as to have minimal clearances, or else the clutch can give trouble. Interesting point about the twisting action of the plate carrier acting on the C20 nut, but there are equal loads either side from two shoes, and the bush in its center should be very lightly lubricated at assembly. I have worked on and rebuilt many of these clutches now (by far the best clutch for a Vincent twin) and I feel that generally the C20 nut comes loose because it is not done up tight enough, this may be because owners see the need to align the slots in the mainshaft with one on the nut, and simply nip it up like they would a front wheel bearing on an older type of car/trailer wheel hub. And also that the factory gave little in the way of torque figures for any of these nuts, not unlike the ESA nut. Most folk these days have no "Feel" as to how tight something should be tightened to, as these trades/skills slowly disappear.......... Some people on this forum including myself will be the last of that generation.
 

Chris Launders

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Should the C3 be flat on the inner end, I came across a spare today a friend gave me and it has a chamfer on the outside almost 1/2 the thickness.
 

greg brillus

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Chris, It is generally just a flat recess machined in the center end of the C3, the flat inner face of the C20 nut actually sits inside this recess or a bit less if the Dowty type seal is in there. I take Vic's point about any back and forth play in the spline of the C3 when placed on the mainshaft spline. Not unlike a loose sprocket on the G4 output shaft that loosens the sprocket nut. That is why I mentioned that generally if this happened to be the case, the outer smooth area that the chainwheel bushes and seal run on, is generally worn as well, and a replacement of the G3 is really the best option. Spline repair is generally difficult and expensive, more so than the cost of a new G3, remembering some of these parts are very old and may have suffered issues for a long time that only adds to the problem. If you have a reoccurring problem, sometimes the only cure is to replace the offending parts..........We are lucky that they are available to us...........For now.
 

Chris Launders

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Greg, the INNER end, where it goes up against PD21. This is an unused spare and I got it because mine is worn on the outside and want to replace it sometime.
Chris.
 

greg brillus

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Sorry Chris I was looking at the wrong end of the stick ....... Yes they do have a small chamfer so it does not destroy the seal within the chainwheel bushes, perhaps the one you have has been "got at" by someone. It may not matter so long as the face is flat, you may need to try it and see if it protrudes through the chainwheel with a bit of end float.
 

Chris Launders

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I was wondering about fitting an O ring in the end but there's not much metal left, I'll wait until I do have it apart and go through it all then.
Thanks Chris.
 

litnman

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I've just checked 3 C20s that were threaded onto a g3 shaft which was set
between centers. Using a dial indicator, one oscillated / wobbled .035, one .020 and the last one .005. With that much run out of the first two, you can imagine how this would cause the C13 to wobble.
 
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craig

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I am refreshing old pieces in my Rapide clutch. I ordered new C14 and find the old 406 screws will not engage fully as they should.
Is this a common problem?
should I return these for correct pieces?
should I just cut off my old 406 screws?

25860
 

vibrac

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Have you spoken to the supplier?
That action is just as important as asking what is to done on here, The supplier may be in blissful ignorance and even now continuing to sell items that may (or may not) be wrong, and in some cases making it even harder for his own recompense from his supplier
We are blessed with a good supply of parts but it is important to keep the suppliers informed of errors that slip through, too often moans about the same parts not fitting by many people could have been avoided if the person to suffer first contacted the supplier rather than bodging the problem.
Put it this way you may be smart enough to sort it the next guy may not be
 
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A_HRD

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Craig,
Just for reference, the Spares Part List shows 406 screw as 7/8" overall length. Also there is a note alongside saying that 3/4" long is OK too. If your 406s meet this requirement then there is a problem with the new C14s.
Peter B
 
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