Premium is not Premium for BMW m/c's here. We have 91 RON max, the bike wants 93 RON which I have had in TX. There I get 52-60 mpg, here, that's quite less, some 8-10.
When I get 1/2 tank of racing fuel (106) plus the 91, the bike runs better, and the mpg is better. But 91 is approaching or over $4 here, 106 is about $8.