Ryan Young recommends 91 octane or better pump gas for the Sherco bikes that he sells. We're lucky here in eastern Upstate NY to have a chain of gas stations that carries 91 octane ethanol-free gas, so I run that. My old air-cooled Beta would ping a little bit on 93 octane with 10% ethanol, but it was happy as a clam on 91 ethanol free. The plastic Acerbis gas tank that it had would swell slightly with the ethanol-laden gas, enough to make it hard to put the gas cap back on. Same with the plastic Acerbis gas tank in my Gas Gas enduro bike.