This is the Ratchet Strap method
use the strap to pull the airbox back into the frame, you gain an inch and a half extra room to play with. This picture is actually one of my bikes and not something stolen from the net although I have put it up on another site before.
I forgot to mention that before you do anything you need to undo the screw on the metal strap that holds the two halves of the airbox together, located behind the right side panel. This needs to be done so that the airbox halves have some movement, the airbox chamber is bolted to the frame but the box that connects to the carbs is held by the strap and the airbox rubbers so is moveable. When the carbs and airbox rubbers have been relocated you then need to re-tighten this strap screw. You will also need to check that the "rubber grommet" seal between the two airbox halves is correctly in place, easiest way is to unbolt the plate that holds the rectifier to the battery box (under left side panel), don't disconnect anything, should be enough room to see all is in order. After enough practice you'll be able to remove these carbs in your sleep.................and that is what Nightmares are made of