Originally Posted by tubes_rock
My Shadow is a 10.3:1 and Honda says run 87. The compression is a small part of the picture.
You can get an engine with a 9:1 ratio to knock if it's hot out and you have advanced timing.
The thing is that sport bikes usually have high compression, run hot, and have advanced timing. All of that spells higher octane fuel, but like it was said,m you may be able to get away with plain ole 87 octane fuel if you're not hitting redline all the time and riding around in 3rd gear all day at 90 degrees.
Get some of the octane booster, and put in regular 87. If it starts to complain about it, dump in some octane booster and shake the bike side-to-side a few times to mix it in.
87 octane isn't any "dirtier" or "of poorer quality" than 93 octane. We've ben brainwashed by the media to think that 93 octane is better, and it's not. Read the Fuelology. As long as it's not pinging while you ride, there's no reason to run higher octane.
Personally, I like to run 87 with a little octane boost vs. getting 89 or 91 octane from the pump. 87 here usually does not have ethanol, and the higher octanes do. (I'm not an ethanol fan...)
I used to do fine on just 87, but since advancing my timing I need slightly higher octane especially if it is hot out. (refering to my spirit 8:1 compression).