I got it, There are plenty of threads on this topic. they all say anything higher than 86 "straight from the manual". What I am trying to find is where in the manual it says this? Ive been looking through mine and I can't find it. Am I stupid?

 

@f4EasyD I answered this in the other post, but I'll put it here too. Page 88 of the 2004 CBR600 F4i Owners Manual. 2001 to 2006 F4i are the same.

 

Pop the rear seat off and should be an emissions sticker sideways on the plastic tool kit area that says recommended fuel type. My 03 says 87