Originally Posted by SourKraut
I should have said at maximum efficiency. Clearly you can make them limp along getting poor fuel mileage, for a while, but the fuel system components are not designed to deal with the chemical properties and impurities of a fuel that is so hydrophilic.
Yes, they are.
Water isn't the issue, everything metal gets water in it when the temperature changes, in fact if you look at most hydrocarbon combustion reactions the results are usually some amount of CO/CO2 and whatnot and water. Remember when all bikes were still carb'd? Frozen carb bowls? Yeah, not going anywhere for a minute.
Ethanol is significantly more corrosive, this is the issue with plastic fuel tanks on older Triumphs and Ducatis the ethanol, even in lower ratio blends like E10 eats the resin sealer or plastic and the tank starts to deform.