Have looked at the commercial offering, which is crazy money, is there any interest in a proper 1 in to 2 manifold with both branches same length and both branches same balance? Yes will mean the carb will stick out a bit but running SU on my shovelheads never bothered me.
If we could do a few in one go it would make it much cheaper than buying one off's
cheers

Hi Gert, I'm not too pre-occupied withe jets / filters and the actual carburation, a good one-into-two manifold will have a good even flow that doesn't tend to favour one cylinder.
In HD this is of course dead easy.
In old british twins it was done with provision for very fine wedge shaped shims (to compensate for errors in the cast heads) that could direct the carburettor slightly more towards one cylinder than the other in case the other was running slightly weaker than the first.
Once you get this basic factor correct then carburation itself is relatively simple, which is kind of where I am thinking of, using something like an SU carburettor (which I used to run on my shovelheads) to make the whole system VERY simple and very robust while still delivering good economy and usable power.
Fuel injection is an option, but if you're going down that road then the inlet manifold becomes less important, just make up two inlet tracts of same length to feed the cylinder and put the injection nozzles at the end of them close to the heads, you lose the simplicity and robustness of a simple SU / Amal type carburretor though... if going for injection I must say there is only one serious contender, megasquirt, check it out at http://www.megasquirt.info/index.html
I've done a couple of these on 4 cylinder bikes (xs11 etc) and they really are excellent, I would consider doing these as a nearly complete kit for the non technical on here if there was enough interest to do a few, but only on a hobby basis, not "here's the money I want the complete thing sent to me within 24 hours by FedEx"...

Yes, manifold is the only "problem" and it's not really a problem, as long as people are prepared to accept that because yamaha used reversed heads with offset inlet ports (unlike HD for example) it means a slightly more complex manifold and a carburettor solution that projects out further than the stock set up....
Once done though there are practically no issues of reliability or poor starting that cannot be completely eliminated with a single simple carburretor of the SU type, the only negative side will be a slight reduction in absolute performance, but since I personally am currently chamging the 35T standard read sprocket for a custom made 29T job (as I feel the TR1 revs too highhly, esp as mine is slightly customised single saddle job (sent the pictures in last week for the gallery) performance isn't really my top priority...
I guess the next decision is on manifold material...
Aluminium means either cast (expensive to make the master) or TIg welded which isn't cheap either, and alloy isn't that strong either.
Steel is strong and easy enough to weld or braze, but heavy.
I think copper will be one of the best materials, plentiful sources of thinwall copper tube in many diameters and radiuses, not passing hot exhaust gases so no problems with noxious chemicals, very very easy to braze which is a very strong and flexible method of welding which is also cheap and accessible to home garage users, and the galvanic corrosion aspect won't apply if we do it properly and retain the original yamaha OEM rubber inlet gaskets.
Comments?