I have a vague memory of Maughans considering an ESA design with Belleville springs instead of the coils springs. If any new designs are looked at, that seems like a good way to go. I'll send an e-mail to the Technical Officer as recommended here.
ET: Engine (Twin) New ESA Design
- Thread starter bmetcalf
- Start date
What we really need is a new ATD design!!!!
I do NOT think any sort of springs should provide the limits in the ESA, instead the shape of the cams must be steep enough to grant a progressive action. That is why I used the idea from the BMW design modified for three cams for the Vincent engine. They had this type from the fifties in all bikes for a reason up till now so that could be called tested and approved. My contribution in the Robinson cam thread regarding ESA design should better have gone into a more suitable place like here, maybe the moderator could shift that as he likes.
Whoever responsible for machining, designing or modifying spare parts, I hope they read these pages occasionally to bump into ideas worthy of consideration. Sorry for not knowing whom to contact first, I just wanted to start some discussions and maybe later we might come up with more radical ideas for promising improvements . The factory design is now more than half a century old and to this day drivers are still faced with same old calamities from day one. Somehow most motorcycle companies seem to have copied the same (wrong) design more or less, pairing very strong springs, single or multiple, with way too shallow cam design. The result is miserable, springs hitting block length plus shocks sent into the primary drive. Springs shall not suffer block compression, breakage is the price. That is why the proper progressive stop has to be the cam set in the ESA, not the springs.
Some more pictures that I did not post in the camshaft thread, but related to ESA:
Vic
P.S. I will happily ship my alu test pair for studies and hopefully used for designing new ESA sets suitable for driving tests.
Whoever responsible for machining, designing or modifying spare parts, I hope they read these pages occasionally to bump into ideas worthy of consideration. Sorry for not knowing whom to contact first, I just wanted to start some discussions and maybe later we might come up with more radical ideas for promising improvements . The factory design is now more than half a century old and to this day drivers are still faced with same old calamities from day one. Somehow most motorcycle companies seem to have copied the same (wrong) design more or less, pairing very strong springs, single or multiple, with way too shallow cam design. The result is miserable, springs hitting block length plus shocks sent into the primary drive. Springs shall not suffer block compression, breakage is the price. That is why the proper progressive stop has to be the cam set in the ESA, not the springs.
Some more pictures that I did not post in the camshaft thread, but related to ESA:
Vic
P.S. I will happily ship my alu test pair for studies and hopefully used for designing new ESA sets suitable for driving tests.
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Could you let us have the diameters of the two new shapes? The smaller/male one looks to be about 15 mm and the larger/female perhaps triple that.
Stuart Hooper used an ESA on his Velo that employed Belleville washers, but I know that they needed frequent replacement. We had a discussion of this is here https://www.vincentownersclub.co.uk/index.php?threads/running-without-esa.8549/ if anyone wants to look back.
I know the post is for twins, but I would note that Velo owners can get an ESA for their belt drive conversions (but Comet owners cannot!):
Maybe that is of some interest to the twin owners also.
I saw this photo of Maughn's ESA, which looked different than stock:
And, there was this ESA for a belt drive, which seemed interesting to me:
Thank you to Oexing for posting and thanks to the Moderator for starting a new post. I don't mind the 105 Cam post wandering, but it makes it difficult to find things in the future.
David
I know the post is for twins, but I would note that Velo owners can get an ESA for their belt drive conversions (but Comet owners cannot!):
Maybe that is of some interest to the twin owners also.
I saw this photo of Maughn's ESA, which looked different than stock:
And, there was this ESA for a belt drive, which seemed interesting to me:
Thank you to Oexing for posting and thanks to the Moderator for starting a new post. I don't mind the 105 Cam post wandering, but it makes it difficult to find things in the future.
David
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Well, the "male" side has three hills/cams with exact 12 mm dia., like BMW, that can easily be milled on a conventional CNC mill. You could do 1/2 " diameters as well if you prefer imperial sizes. These 12 mm shapes are cylindrical, no tapers or whatever. The trick is to use just that diameter in form of a 12 mm end mill for milling the female side. I let another DRO counter calculate positions for a circular hole pattern with steps about half a mm apart, I think, could look up my sketches. So basically the big valleys were sections of circles or radii , but you cannot machine that shape easily, you have to merge each step by positioning the cutter in , say, x-bedway plus "fake" y-position by turning the dividing head a fraction of a degree. The end mill will stay in the zero y position all time, only the x-axis gets new coordinates. I must confess most of the details I do not remember easily, that was half a year ago. But in the photo in the paper file there must be the x-positions and the corresponding degrees for the dividing head dialled in by reading the small DRO on the mill wired to the rotary encoder of the dividing head. I don´t know if I can find words to pass the idea but basically you have to simulate the positioning exactly like the ESA does on the mainshaft when it lifts and rotates under torque from the chain drive: The male partner does a few degrees and gets lifted by the female shape a fraction of a mm , the male half does a few degrees more, gets lifted a little bit more and so on, in the end the contact with the female shape reaches a lot steeper gradient and you get a very progressive damping effect so the assembly does not need to rely on blocked springs at max. torque. Maybe a few more pictures show the idea better. Anyway, in the frontal view of the modified ESA you can see that the female valleys have no parallel sides at all, but my theories were confirmed with the very first try, the alu patterns, and checked with a little bearing blue. The progressive action from the new cams can be tested by finger feel, just that I do not know the person and address I could send the alu test set .
Vic
Vic
A couple of years ago I saw the new ESA prototypes at the spares company. The cams showed full face coverage over the range of movement compared to what had been supplied from Maughan's for the last twenty years. The change of spring type seems to me to be a further improvement and needs to be tested.
i used to grind in the VOC spares ones in with course valve carborundum, thats takes a day...... nowadays its good, but still dont like the slack in them...... we dont need that, only cushionning the high loads, I like the steep ones, like i saw from Velocette or?,
BTW if one uses Belleville washers, be sure to have at the back end some PUR 95 shore hardness, so it does not really lock up.
BTW if one uses Belleville washers, be sure to have at the back end some PUR 95 shore hardness, so it does not really lock up.
Bruce:
example: like a vinnie from seen right to left side:
primary sprocket with lobe- lobe on crank spline- bellville washers- ring-PUR 3 mm- big ring- Nut.
example: like a vinnie from seen right to left side:
primary sprocket with lobe- lobe on crank spline- bellville washers- ring-PUR 3 mm- big ring- Nut.