Octane rating is an efficacy rating on how the fuel burns. The more efficient the fuel burns the less problems you will have. I get my best mileage on 93 octane and the smoothest engine performance. If I can't get 93 or 91 octane I put just enough to get to the next fuel station. I also carry octane booster when doing trips where higher octane is not available. Much more than 98 octane is too efficient for my bike it burns to efficiently and that translates to heat. All that being said my owners manual calls for 91.LOL

 

93, or 91 if I can't find 93. Tried 87 one time and the bike ran like crap, pinging, knocking, rough idle. Figure for $1.50 a tank I can avoid problems. Why would you worry about an extra $1 or 2 after spending $20K+ on a bike.

 

When gas hit $4.00 a gallon, I tried regular with no ill effect, and have stayed with it.

 

93 (around here it's 87/89/93) and Shell, BP, or Exxon.