Sorry if this post is out there already... I couldn't find it. So I bought a 400 recently and the P.O. used strictly 91 octane in the bike and never had a problem. I know it is supposed to run 95 or higher. So if my bike runs fine on 91, is there a reason I should start using the race gas? Is it meant for better performance, or is it hurting the motor even if it does not ping or knock? Thanks.