With my motorcycle, over the past 80,000 miles and 9 years, I've had the opportunity to buy many different brands of gas in many different states. However, one brand of gas burns completely different in it. The engine is quieter (less chatter), and it has more pep. The one brand of gas is Casey's General Stores... and not Amoco, Shell, or any of the other major brands. I've ran the bike low, and have filled it up at different Casey's outlets, to have as much of the different brand of gas in it as possible. I'm stunned about this, as I would have expected gas from a convenience store chain would be marginal at best. It seemed that I could tell a difference in gasoline brands with my last motorcycle as well, but racked it up as a coincidence. However, it seems that as a motorcycle ages, the differences become more obvious. Or am I nuts?