Flexible Fuel Vehicle, a Vulcan modified to safely run on fuel consisting of 85% Ethanol (corn oil, I believe.) Ethanol is highly corrosive to rubber, and I believe other parts normal to the Vulcan, so the FFV vulcan is beefed up with parts that can withstand the corrosion. Also, Ethanol has a much higher octane rating (upwards of 100), so the FFV Vulcan is designed to take advantage of the higher octane rating. Take away the Ethanol, and it's the same Vulcan.