I ride Katana 600, no 'Busa yet, but I think 40 - 42 is way too high. That sounds like maximum tire pressure that's written on the wall of a tire.
I would think it should be in the mid 30's.
BTW, on the track recommended pressure is 30 - 32 regardless of the bike.
I ride aggressively on the street, and keep it like 32 front/34 rear. Manual says 33 front/36 rear.
Someone pointed out a while ago that such high pressure in the manual could be just a liability issue that Suzuki doesn't want to deal with (if someone forgets to check the pressure and rides with too little pressure following tire failure). So, they recommend the highest possible number.
But, you won't get good traction/tire temp with 40 - 42.
<!--EDIT|IG.
Reason for Edit: "Damn! Just noticed it's pretty old thread."|1068594409 -->