Snatchy clutch or Kangaroo petrol?

nkt267

Well Known and Active Forum User
VOC Member
Hi folks,,the fun starts here..
I now have a '48 Rapide to go with the Comet.
Left the factory in December 47 and was registered February 48.
I new about the few things I had to work on when I got it and most are not a problem,BUT---- the clutch takes up very fiercely to the extent that if the wife was on the back she would most likely disappear when i pull away.
Lots of reading but all I can find is that snatch is caused by the shoes not being chamfered enough..I DON'T BELIEVE IT..
I stripped the clutch and found that C13 does not have a shim between it and the nut, about 35thou endfloat.
The plate carrier can rock a lot on the nut so it looks like the bush is worn.The C10 links are oval and have about 10thou slop on the C14 clutch plate pins.The pin clip is boken in 3 places and a couple of the pins are now floating and chipped at the edges.
C7 has a badly worn plunger hole and the plunger moves about a 16th inch at the end but the pressure seems ok the C7/1 plunger is stiffer but its housing is ok.the springs are all different lenght and need replacing.
now,how worn out does a twin clutch need to be before it ends up not being unusable.I am getting the feeling that it would almost be better from the cost point of view to fit a multiplate clutch,,,any views on this?
Yesterday I road Sprot's Rapide--very nice standard clutch--for the first time and also his Swedish Shadow,Geeze that thing goes. So I know that the clutch on mine is BAD..
Any more ideas to get me on the right track please..John
 

Simon Dinsdale

VOC Machine Registrar
VOC Member
VOC Forum Moderator
Stu Spalding has been sorting a badly worn clutch one step at a time to see what particular part was causing the greatest problem with pulling away. He said getting the plunger in the bore to operate smoothly was the greatest improvement. This was done by opening the plunger bore and reclining with a thin wall bush. Then replacing the two plunger springs for a single spring of equal strength to remove the spring coils rubbing. This created a smooth plunger operation and thus eliminated the kangaroo effect. If there is the slightest sticking or jamming or tipping over of the plungers in their bores the clutch can be like a on-off switch.
 

nkt267

Well Known and Active Forum User
VOC Member
I have seen on Peter Sprot's twin that too much pressure on the plungers can cause the clutch to slip,so I do suspect that the plunger operation may be the primary problem..John
 

Bill Thomas

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VOC Member
Hello John, You do know that the shoe plungers Should Not be the same strength, I can't find it in my books, But the info is there somewhere, Best tip I have had is to make sure the shoes don't touch the drum if you spin the shoes by hand, I think it should be 20-25 thou gap, Lots of people have had the same trouble with the Multi plate clutches !! So I would stick with what you have for now, Good Luck, Bill.
 

Bill Thomas

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VOC Member
John, have a read at www.thevincent.com at the top of the page press on Clutch, Just a few points, The plungers should be touching the pins at rest, Mine were worn out and I fitted small sleves over the pins, If the pivot hole in the shoes are worn, I think you can drill it out and fit a camshaft bush, Not sure but I think thats what I did, Cheers Bill.
 

Michael Vane-Hunt

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VOC Member
I struggled with my bike not shifting properly. I endlessly fiddled with the shift mechanism under the kick start cover. Finally after listening to some people at a recent rally I changed my focus to the clutch. Took it all apart then ordered new relined shoes, new c14 pins, new c15 sleeves, new c9 link pins and new c16 spacers from the VOCS. All the parts I replaced were probably with the bike since new. The clutch shoes come complete with plungers. I put this pile of bits back together, paying attention to get the correct end float and I also put a single flat washer on the c14 pins behind the c21 inner clutch plate. This transformed my shifting, making first and neutral easy to find, no grunching when putting into first and good shifting up and down. This is the first time in 30,000 miles that my bike has shifted well, and for some reason seems to start more easily. Mike
 

nkt267

Well Known and Active Forum User
VOC Member
[QUOTE Remove entire engine and gearbox, replace with Comet units. Problem solved. :)][/QUOTE]
Couldn't get 2 in there John:p..John
 

nkt267

Well Known and Active Forum User
VOC Member
paying attention to get the correct end float
I still can't find any reference in either Stevens or Richardsons as to the amount of clearance between the clutch nut and C13( I assume near zero clearance but free to rotate).I would like to find out how much clearance there should be between the plungers and C14 in the freed position..John
 
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