A confusing art. I am still tryibg to figure this out. Keith's bike was too lean with a 45 pilot since the fuel screw needed to be several turns out. The mid and top end were to rich with the 170 main and the needle setting. When the pilot was increased to a 48, that was too rich also. But when the main and needle were both leaned, and the pilot was returned to the previously too-lean 45, all is now good with the fuel screw. Huh?? A lot had to do with not warming up the bike properly. You should run it at normal speeds for at least 20min. Do an initial driveway adjustment on the fuel screw after running it around the block for a while, and then do a fine adjustment out on your next ride. Write down in a log book how the bike ran in a certain area with what jetting, then next time you do not have to screw with it. Pun intended. The fuel screw should be adjusted for each major changing condition of altitude. Also as many have said before all bikes are different. I am not expert, just reading the info on this board about the FCR carb and messing with my own bike helped me a bunch. The info is here you just have to dig a little.