ET: Engine (Twin) Engine Shock Absorber

erik

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The reputation of the BMW for durability founds mostly on the poor power output of these bikes for the days when they were built.And for this low power output ,60 to 70 PS, with 1000ccm the gearboxes were to weak.My R75/6 had only 50 PS and the live of the gearbox was not really long.Not a german masterpiece in engineering,sorry.Erik
 

oexing

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Just to be clear, I am not a BMW taliban, nor am I a Vincent fundamentalist. But when I find crap designs I say so, and crap you find in ALL types of machinery. So from long experience with many types of bikes I can tell what works and what doesn´t - from gut feeling and drawing conclusions not maths . And I do not want to say this or that brand is great but try to draw benefits from all types to achieve reliable results. So when pointing to this BMW type ESA - or the Kawa 1300 version - I had reasons to do so. The Vincent ESA is crap - period - and some more details as well . No matter how you paint it, there is scope for improvements with a radical change as I have tried to explain - and am a bit puzzled that my views seem a bit hard to follow ?
Yes, with BMW or Kawa ESA there is some axial loads from springs acting at bearing inners and some wear as well, but nothing like with the Vincent miserable flat lobe shapes when only very heavy spring loads are meant to stop the twisting motion within the ESA. The BMW lobes rise to a steep gradient over 45 degrees so when remembering force vectors in school you may get the idea that most of the torque is contained in the lobes unlike in the flat Vincent ESA lobes , that turns all forces into extremely high axial loads via the sprocket onto the inner race of the outer bearing - with a lot of wear - and which you do not get in BMW gear boxes.
In Vibrac´s project , using a belt drive (?) I see a problem with durability like Vincent Speet said above: The twisting motions in the poly dampened design will produce either wear in the cylindrical sprocket fits or seizures when no oil lubrication due to belt drive there.
Seizure is no big problem in a chain/belt drive machine I think, no non-effective ESA so no problem. But wear will be bad for the drive and not easy to avoid without oil lube. So not yet a finished design.

Vic
 

erik

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Vic I can follow your arguments for 100% about the lobes of the ESA .Pre war NSU had the same design like the Vincent. Erik
 

Vincent Brake

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Have a look at the Triumph T140 clutch hub.

Thats the way to go.
Bit reengineering as the wear can be high.

Them little pins on the comet s sprocket are too small for effective surface.

Put in a black spider....
 

Martyn Goodwin

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There seems to be two (or more) topics here.

Just to be clear the Alton electric starter/ESA combination IS NOT suitable for use with a belt drive primary. It was designed around a Burman clutch but works equally well with a Conway's Honda clutch. The 'redesign' of the ESA by Alton (see posts #9 and #11) was a necessary change in order to ft all the bits onto the mainshaft while staying within the confines of the original primary cover.
 

vibrac

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Not two topics you should.be on the thread 'comet electric start ' this thread was started when BMW shock absorbers took over :)
 

BigEd

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There seems to be two (or more) topics here.

Just to be clear the Alton electric starter/ESA combination IS NOT suitable for use with a belt drive primary. It was designed around a Burman clutch but works equally well with a Conway's Honda clutch. The 'redesign' of the ESA by Alton (see posts #9 and #11) was a necessary change in order to ft all the bits onto the mainshaft while staying within the confines of the original primary cover.
I think Martyn's post is probably relevant to both threads so I've added a copy to the "Comet Electric Start" thread.
 
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