I run 93 octane because that's the minimum octane my engine was designed to run. Low compression engines will run fine on regular. When I take my bike to the lake, I buy from the Chevron station there because they have NO ethanol. A non fuel injected engine will run better w/o any alcohol, because ethanol produces less BTU's per pound than gasoline. Alcohol makes for a sorry street fuel but a great racing fuel because it will handle up to 17/1 compression. It will make more power but requires twice the fuel to do it. I would be more concerned with using high quality synthetic oil than what gas I'm using. The plating on these engines can be destroyed quick with cheap oil.