C: Clutch Refreshing Vincent Twin Clutch seals and pieces

Hugo Myatt

Well Known and Active Forum User
VOC Member
Just a word of warning. About thirty years ago Tony Maughan produced a different seal in place of the C19. This comprised of a thick alloy outer ring with an O ring internally. These necessitated a much shorter C20. Whilst these Maughan seals are long unavailable there are a number of these shortened C20s still out there leading to confusion and frustration. If the clutch won't go together without locking up the shoe carrier C13 check the length of the C20.
 

vibrac

Well Known and Active Forum User
VOC Member
Just a word of warning. About thirty years ago Tony Maughan produced a different seal in place of the C19. This comprised of a thick alloy outer ring with an O ring internally. These necessitated a much shorter C20. Whilst these Maughan seals are long unavailable there are a number of these shortened C20s still out there leading to confusion and frustration. If the clutch won't go together without locking up the shoe carrier C13 check the length of the C20.
That sounds like the little 'item' that foxed me all those years ago (see above)the alloy of the seal looked for all the world like part of the component it finally it revealed itself at the point of a scriber:oops:
 

Peter Holmes

Well Known and Active Forum User
VOC Member
I am not sure that you are correct Hugo, I also had the same clutch seal mod done on one of my engines by Tony Maughan, the alloy outer ring may be a little thicker than the bonded seal C18/1 that it replaces, the internal O ring is simply compressed to the same thickness as the alloy outer ring when the C20 is tightened up, the C19 is in fact a shim washer, not a seal, the variance in between the thickness of the alloy outer ring and the C18/1 can easily be accounted for by the use of a different thickness of C19 shim, if the C20 was much shorter it would simply lock up the the C17 clutch centre bush. I think Maughan and Sons can still supply the two part clutch seal mod if asked. The real culprit can be the lip on the C17 clutch centre bush, if that lip is too thick you might have to use the very thinest C19 shim to avoid locking the clutch centre up, and that thinest shim is far to thin to be used by itself and can be a recipe for disaster if it breaks up, then the C45 spring tang has a tendency to snap off, the C20 unscrews itself and before you know it you have lost all effective use of your clutch lever, as happened to me in the middle of Dartmoor this summer, I managed to limp back to Gulworthy in 2nd gear, and then of course visited Marcus Bowden, problem solved.
 
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Hugo Myatt

Well Known and Active Forum User
VOC Member
Pete,
I bow to your greater knowlege but when I reverted to the original type seal I found that in no way would the Maughan C20 fit without locking up the shoe carrier. It was definitely shorter than standard. I had to purchase a standard C20. I still have it Maughan C20 somewhere but I put it in a 'safe' place so that I would never get them confused again.
 

craig

Well Known and Active Forum User
VOC Member
I am pretty sure I replaced my G3 clutch shaft assembly with a new G3/1. I would like to know the specific difference please. It appears all you need is a spacer? to convert a G3 to a G3/1?

MO16details1.jpg
 

stumpy lord

Well Known and Active Forum User
Non-VOC Member
for a picture off
I am pretty sure I replaced my G3 clutch shaft assembly with a new G3/1. I would like to know the specific difference please. It appears all you need is a spacer? to convert a G3 to a G3/1?

View attachment 25284
for a picture of G3/1 see page 136 off Into the millennium or M.P.H. 742. it also gives details. of the part C3 C3/2
For alternative methods of sealing the clutch nut see know thy beast page 118.
stumpy
 

craig

Well Known and Active Forum User
VOC Member
Thanks stumpy, I went and found my 742 and was amazed to find pictures of the shaft end. I had never seen a G3/1 and it's clutch end modification. Now I see how a G3 coiuld be made into a G3/1 with a spacer.
I hope it is okay to share the page 11 & 12 of MPH.
Craig

I am disappointed that C20 and C20/1 are not shown and discussed, and that a photo or better yet cross sectional drawing of the assembled G3/1 and C3/1 are not shown.


MPH742Pg11&12.jpg
 

craig

Well Known and Active Forum User
VOC Member
My KTB, forth edition VOC 2003, has the C18/1 and C18/2 combination seal discussed on page 129.
Thank you.
A seal combo for me to consider.
 
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vibrac

Well Known and Active Forum User
VOC Member
There is a problem associated with different versions of the C20 nut I tried to search on the forum but C20 is not a long enough search term.
Hasnt one got a recess and the other not?or one is shorter than the other I seem to remember I had the wrong nut on a new bike and a deeply embeded oil seal that looked like part of the assembly it took a lot of pondering before I realised what was up .
It was a long time ago and pre forums it could be lonely in the workshop back then....
Thank you all for helping me remember
 
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