I am tired of posting all the details, but as a chemist, I can tell you that a stock Busa will run best on 87 octane.
GUYZ and GALZ, the LOWER the OCTANE the HIGHER the performance!!! AGAIN, the LESS OCTANE THE MORE HORSEPOWER!!!!!!!!!!!!!!!! This is true!!!! Octane refers to additives that lower the ignition point of the fuel. Why would I want to do that? Because if you have high compression, the fuel will ignite WITHOUT the sparkplug firing. Higher octane fuel will not suffer from preignition like lower octane fuels.
So what about my buddy, he runs 10x faster with 190 octane fuel... well, call Bull sheit unless he is also running 18:1 compression.
This is the greatest myth in motorcycle performance... except perhaps the "motorcycle certified oil" myth.... sorry folks, that is BS too! Take it from the guy would worked for the chemical company that made the additives....