just from what i know about ethanol on gasolines, it is a solvent that eats rubber, it melts rubber (gaskets, o rings etc..), our bikes are ethanol ready so no worries to that, the problem here is that ethanol is hydroporic, it attracts water, our carbs have a fuel reservoir, any fuel that has ethanol on it attracts water so if theres water mix in the carb as well as on the gas tank, thats when you hear the engine cough and sputter, thats a fuel mixed with water in the engine...worse is that water corrodes the metal part of the engine, specially piston rings..in fuel injected engines, the story is different..