Thanks for the pics. I've never seen an airbox like that before fitted to an RS.
I wonder what sort of spec the 'over the radiator' type of airbox fitted to my RS is?
I do have a couple of pics of a set of Keihin carbs fitted with similar 'plumbing' to yours and have read an article relating to the 'plumbing' for (I think) fine tuning of the fuel metering/carb set up. For the life of me I cannot find the article now though! Doh!