Just disagree about the value of messing with float needles and seats on stock chopped carb set up on bike that is going to see usual "vintage" use. But I'm not expressing a "political opinion" (i.e. in the scheme of things none of this is all that important and this is supposed to be a fun hobby.)
In Reply #6, i pointed out the fuel delivery limitation of the chopped set up, and that dual full carbs did not have this limitation. I pointed out a monster needle and seat could overcome, or at least mitigate, this deficiency. Piero then took this thread in that direction. As it is his thread, so be it.
In the "vintage" use, it does not matter ..... running out of gas occurs at high power loading where the vintage user may never, or seldom go. However, some of us love the exhilaration of feeling that strong push right up to 6800 rpm, and vintage or not, like to stretch the legs of these machines.
This discussion of fuel starvation may be useful to those dual Monobloc equipped, Atlas engined, bike owners who have accepted that these machines "poop out", or do not have the "guts:" over 5K rpm, when they are simply leaning out as the needle and seat fails to keep up with demand. This Forum is to fill such an information void, and such is my purpose in explaining the nature of the problem, not necessarily promoting a "cure".
As a further aside, IMO, I think the air flow dynamics, and the internal fuel metering dynamics of the concentric carb, offer no advantage over the Monobloc, as both are essentially the same. It is that each concentric has its own needle valve that provides the user with a performance advantage. There is a space saving advantage to the concentric as well.
BTW ...... can you answer Pedro's question about "slide heights"? I can not.
Slick