91 is not "better" for the engine in any way.the dealer recomends 91 to help keep the bike in top running order. you can run with 87 but at only a few pennys less I will treat mine to the 91 only. you get over 60mpg so I dont see why you should use less. just for fyi there is a big difference in 87 and 91 but it is your bike.
have fun all
Some gas stations do not put ethanol in their premium fuel. I have not found one near me but in Ohio there were plenty.Its a good idea because of that ethanol crap to add a cap of fuel stabilizer to each tank to keep it clean.
Its basically equivilant to a cheaper option than using those lucas or seafoam or whatever.
Use em in small proportions every tank is much better than once in a while to clean it out.
Dealer told me to use premium and that is what they put in the tank..premium = 98oct?