C: Clutch Twin Primary Chain PD1

[oexing]

Yes, but the original design was wrong from the start - as with other ESAs from pre-war that got copied without thinking . That shallow cam profile may have been allright for 15 hp sidevalvers and maybe one fat spring, so the whole lot survived long enough. But really a lot more progressive action within the cam profile is required for a smoother damping effect. I still did not see a photo of the "new" reworked profile and I guess it was just corrected a bit to prevent chipped edges which was another defect due to poorly mating faces - a problem of complicated manufacture. But this does not help with the slamming onto full lock. I have no clue how they did it half a century ago, to achieve an acceptable shape somehow.

Vic

 

[BigEd]

there has been a revision (or perhaps just a new drawing) of the cam profile about a year or so ago by the VOC drawing committee (I guess thats who are referred to as 'Club Gods' above) I am not sure of the details but I think as normal policy it was to ensure it was exactly to Vincents original design, whether that implies some non drawing committee cams perhaps from outsiders previously available had strayed from the original I could not say

I think that Tim Kirker had the new profile shock absorber at an AGM a couple of years ago. Ian at the Spares Co. might be able to tell us more.

 

[stu spalding]

Vic's ESA cams look very similar to a BMW profile. My brother runs BMWs and never has any complaints about their ESAs. Cheers, Stu.

 

[timetraveller]

I saw the new 'works' one at the VOC SC a year or so ago. Without measuring it I cannot say too much but my impression was that it was a tidied up version of the original, nothing as different as Vic's. Some time ago I put a CAD drawing of the change in resistance for Vic's system on here.

 

[oexing]

Stu, you are quite right, I looked at my Earles fork BMW gear for inspiration . They had this design from mid-fifties till modern flat four K-types, maybe later . And I found a picture of the Kawasaki 1300 four gearbox, two of these ESAs inside , same design, for a reason. Recently a friend told me, Moto Guzzi has made same mistake like Vincent or other types in copying the olde cam shape for their V-Twins - and got same troubles with chipping edges due to poor fit. Chips in the gearbox are not what you´d like to have !

Vic

Kawasaki gearbox:

BMW R 100 ESA :

Kawasaki Z 1300 gearbox:

 

[greg brillus]

Its a difficult one, there are several ideas I have thought of, that if a revised or altered version of a part was made how much better that would be. A small example is look at the slop in the fit of the C5 pins and the 1/2" pivot hole in the standard clutch shoes...........If those C5/1 pins were available in a couple of over sizes, all you would need to do is true up the bore in the clutch shoe to remove all that sloppy play and return the shoe back to service. Of course there is nothing wrong with making small batches of these parts and making them available via MPH or on here, for those who are interested to decide for themselves. To the credit of the VOC Spares co, I guess there is a limit to what they can be expected to provide. There are an infinite amount of improvements we can make to these bikes, that's is one of the reasons it is great to have a forum like this to share these ideas even if the masses don't take notice. A perfect example of that is the new steering stem mod that Timetraveller has provided ........ probably the best single mod and safest you can carry out on any Vincent with Girdraulic forks ........ and that is far, far from ever being installed to all the bikes out there. It is a mandatory mod as far as I'm concerned.

 

[timetraveller]

I picked up another 20 steel and four ali ones three days ago. They are now pressed together and shipping will start in the new year. When those are fitted it will be getting on towards 150 new systems.

 

[BigEd]

........... There are an infinite amount of improvements we can make to these bikes, that's is one of the reasons it is great to have a forum like this to share these ideas even if the masses don't take notice. A perfect example of that is the new steering stem mod that Timetraveller has provided ........ probably the best single mod and safest you can carry out on any Vincent with Girdraulic forks ........ and that is far, far from ever being installed to all the bikes out there. It is a mandatory mod as far as I'm concerned.

The bikes with the fork mod are probably the ones that the owner is planning to ride rather than look at.