Rec 90 Ethanol Free gas vice 91 octane requirement

I have a 2019 Yamaha GP1800R with Riva Racing Stage One Plus performance kit. The stock GP1800R is supposed to use 91 octane gasoline.

Seems like most land based gas stations and most on the water fueling stops use Rec 90. That is ethanol free 90 octane gas. Given the stock requirement is 91 octane and the fact that I have the Stage one plus kit installed, can I use use Rec 90 gasoline?


I’d recommend a little bit of octane booster to make sure you aren’t knocking.