I was also thinking the pilot air jet can't be different enough to hurt, and I also noticed that dynojet and factory pro don't replace this, so probably isn't considered that important (good seeing as one on them is now permanently fitted!).
All the orings got replaced - incl the main, so should be good there. I'll move the needle clips to fifth down before I re-fit them as you suggest (which raises the needle & riches it up, correct?). Yes they both have a washer on top of the needle - I managed to lose one but Allen's had one of the same size in stock so got that with the replacement needle jets.
My problem definitely isn't with the main circuit as beyond half throttle the bike pulls very strongly up to around 9k rpm (IIRC my old M900 ran out of puff around 7.5-8k). Headers & cans are definitely not stock (SR-Racing on the cans, presumably they did the headers too), and the airbox lid has been cut open (and then a metal strip silicone to the front - see pic below), which I've put the fresh pipercross filter in.
Thanks flip, that's given me some reassurance that I'm headed in the right direction at least.
Just looking at the valve clearances as we speak, and I haven't found any evidence of other vacuum leaks, so if the valves are all good then fingers crossed the carbs just needed a good clean out (and possibly new needle jets).
