I have an '01 R6. I've had it for about 4 months now and has been running perfect until the other day. Whenever you give it gas it hesitates and sputters and losses a lot of power. I thought it was bad gas because on mistake i put some Valero gas in it when i usually run Chevron. I drained the tank and left the tank off and ran the bike without the tank on so all of the gas in it would be gone. I replaced it with supreme Chevron gas and once i got home, took the gas tank back off and rode up the street to see if the problem was still there, which it was :?: I don't know what to do :?: The bike has 13k miles on it now, i bought it when it had 9k and not sure when the spark plugs where changed. Could the spark plugs be fouled up? I drove the bike with the gas tank and the fuel filter off and it still ran bad? Are the carbs dirty? Any help would be useful before i have no choice and take it down the the dealership to have it checked out.