since i dismantled/refitted my first 550 airbox a couple of years ago i'm convinced those japs originally held an airbox in mid-air and constructed the frame around it.... my latest attempt to solve the problem was with carbs in situ: unbolt/remove battery-box and sqeeze in airbox from the right hand side (some serious swearing at this stage does help), adjust (don't forget to put those clamps on), re-install filter box and battery holder, sit back and have a beer (or three). if you've done that a couple of times, you may do it in less than five hours (chris in ramsey - eat your heart out :-) ). either way it's a real pain but can be done without cutting the frame.