Chris Launders

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Cheapest method and possibly best, get a steel front pulley and machine/weld to the comet sprocket centre then alloy clutch basket, so you will still have the cush drive and a pocket full of cash. you don't run a belt tighter than a chain (see above) and certainly won't destroy a Norton box. I've been running a twin motor/ belt drive/Norton box over 15 years.
 

Jez Nemeth

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Often the sweet scent of low price is outlasted by the bitter taste of low quality, but that sounds pretty realistic Chris..be some measuring involved. So welding to the ESA sleeve then, or turning down the Vincent sprocket -welding a steel pulley to it -using the ESA + spring set up with a belt? That's kindof ideal. Got to be careful, need to be running a 32 toothed steel pulley on the shaft -be tight. Any adverse issues with the belt bunching under gear changes?
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Chris Launders

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No No No, I don't have a Comet but you should be able to work out a way of turning the sprocket down and the pulley out so you can weld them together and keep the ESA., in effect the inner of the sprocket with the outer of the pulley.
 

Jez Nemeth

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Chris, my curiosity and bank balance thank you for this...will be looking into the parts tomorrow -RGM Norton and a few others are good sources for the bits. Must admit, was curious about doing something of this ilk -glad to hear it works and well -sounds best of both worlds.
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oexing

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Best option is NOT to install the Vincent ESA and you will never have any problem there. What that crap device really does is braking even triplex chains - as is well known.
Where do you think will shocks develop, from the rear wheel, from the primary drive ?? The crankshaft is quite heavy and will not induce any big shocks into the drive within one cycle. Chain drives are not as rigid as shaft drives like on Guzzis or BMWs. So , as Neville Higgins has found out, that non-elastic shock absorber slams onto both limits when accelerating or braking the engine, no damping at all due to its shapes. I bet nobody has ever snapped a belt in a non ESA setup, or a decent chain in no-ESA bike.

Vic
 

davidd

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Jez,

You have confused me with so many choices!

Greg rightly points out that the single primary ratio is higher than the twin and with the 36T Newby engine pulley and the 68T clutch the primary ratio is very close at 1.89. Like Tim, I prefer the quality and reliability of the Newby. It is difficult for the other options to match the overall performance of the Newby. The extra cost should pale when compared to the performance and reliability of a Newby.

These belts have no give in them. They are the same as timing belts and you cannot have give in a timing belt. I do think that racing may prove to be somewhat easier on the primary than stop and go driving. But, on the other side is the excellent clutch. I believe it is a better shock absorber and it is able to be slipped often without any damage.

Finally, the Newby fits inside the Comet primary with some mods to the inside of the primary. That saves a little cash and protects the whole primary.

David
 

Chris Launders

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I must admit mine has no has no cush drive anywhere and consequently is a bit harsh, I have a picture of what I consider an ideal one , although I am considering changing my Manx back wheel for one with a cush drive in it.
 

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Jez Nemeth

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David, You put it succinctly -and yes, indeed I am similarly a little confused -its why felt the need to post initially, but less so now. Belt drive would seem the way to progress, unless the conversation heads towards a "Chain vs Belt" -for and against conversation then we're into another ball game...Newby does seem to be a fully sorted well tested system -highly regarded by everybody, and yes quality comes at a price...choices!
 
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Jez Nemeth

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One other consideration that may ultimately swing it -Norton Commando clutch basket fits, with very little room but it does. If running 58 tooth clutch, AT10 Belt, the front pulley diameter for 1.8 ratio = 32 teeth (32.2) + Flange is 4" 3/8 total diameter, fits with a bit of dremmeling, but tight...represented here with correct sized card disk. The Newby I'm assuming is a better fit and possibly an easier clutch? (Been watching Comet Mongrel avidly on how to make a Norton clutch easier on the lever). Great advice, and considered responses truly appreciated -learnt a lot in a few short hours.

So it seems to come down to either a home grown belt solution, or the Newby system. That's a big step forward from where the thinking was.
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Chris Launders

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You could easily go down on the engine pulley size, there are a vast range of gearbox sprockets for the Norton box to take it back up and you're nowhere near the Hp/torque figures of a Commando.
 
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