Adding a lock washer to a Comet PD7

craig

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VOC Member
I wanted to add the lock washer system from a series D Vincent (MO93) to my daily rider Comet.....so I bought all the pieces
PD7/2
PD35
PD5/2
PD6 and 27
PD3/3
And then found that this system will not fit into a Comet primary cover....too large.
So after considering what might work, I decided I could fit the lock washer PD35 into the existing Comet ESA with a little modification.
So I cut a slot in PD8
Removed a tab on PD5
and everything fit.
However after fitting all together it was apparent that the new tab washer tang, using a slot on PD4 for lock, was going to prevent the ESA from sliding and working.
PD7LockWasher3.jpg
 

craig

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VOC Member
Since all my lock pieces had moved on to a twin, I did not have any parts to examine anymore. So I pulled out my trusty spares catalog for B/C and D .
And simply reviewing the pages I find the PD3/3 , designed for lock washer, has all the splines recessed to clear the lock washer tang.
Has anyone been here before?
I think I should only reduced one spline on my existing PD3/2 for this system to work..............rather all splines .
Experience?
Thanks
Craig

PD3LockWasherRecess.jpg
 

craig

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VOC Member
So I reached in with a Dremel, using a thin cut off wheel, and removed about 0.250" of one long spline.
There would not be any clocking advantage by removing material from other splines.

20151219_CometESAMod1.jpg
 

craig

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VOC Member
pre assembly check shows all the pieces installed on an old drive shaft, and using some small tubing pieces to simulate the ESA springs.
The travel of this ESA is 0.228", about half way up the cam action.
I had shortened the lock tab about 0.090 , really did not need to.

20151219_CometESAMod2.jpg
 

timetraveller

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VOC Member
It looks a lot like most of the ones which I have seen BUT. I know someone who had access to a stroboscope and he checked the action of the 'C' ESA. His expression as far as I can remember was "it's like a switch". By that he meant that as soon as any pressure was put on it it moved as far is could up the ramp and stayed there. No moving up and down to compensate for varying torque coming from the engine. Dick Sherwin also fitted one of the beefed up Australian one and after a few thousand mile it was taken apart and found that it had hardly moved from the 'at rest' position as shown in the above photograph. So there seems to be the need for some careful tuning of the springs, the standard being too week and the Australian set up too strong. Perhaps a 'D' has it about right.
 

craig

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VOC Member
The ESA PD3/2 and sprocket ET60/1 cam profile is what you would expect to see if both were new. I think this set has 20,000 Comet miles on it.
Maybe more. Don't know about the 18 (18+18)springs, but this ESA is standard for any stock Vincent.
 

craig

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VOC Member
Here is what I used to get slot put in PD8.
Started with a small file to get width established, then followed with a 10" flat file , that has edge serrations, to quickly cut a deep slot.
20151219_CometESAMod4.jpg
 
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