I tried 98 RON but had starting issues. There was an ecu update (reflash) earlier last year that overcame some fueling issues. Improved the starting but still took a few turns. I run 95 on the recommendation of the dealer's service manager, and 91 if I can't get 95. I avoid E10 or (obviously) E85. More than happy with 95, the bike seems smoother than on 91 (of course that's not any form of scientific test, just seat of the pants feeling).
Note this is in Australia and our fuel has a reputation for being crap.
She's not an Italian supermodel
; they're high maintenance.
She's the cute Italian girl from school
you wish you kept in contact with...