your book should tell you what the play is supposed to be. I think on the busa its 20-30mm taken when the kickstand is down.

also, make sure that your front sprocket itself isnt loose when you take the parts off to check the bolt, check the teeth to see if they're worn or bent. sprockets are cheap, i got a -1 front for about 15 bucks.

Lube every 600 miles or less.