A little background here, ethanol is added to our gasoline as a cheap cleaner burning alternative to octane boosting chemicals. Since the ethanol has more resistance to combustion and less BTUs than the petroleum base it does a very good job boosting the anti knock index. Also as late as the 1940s there were gas stations in the mid west that only sold 100% ethanol gas. Early Ford engines were designed to run on this as our nations infrastructure hadnt developed to the point where petroleum based fuel was readily available, but most small towns had the ability to distill alcohol for fuel. Also leaded fuel had little to do with valve seat switch in older engines. Engines began to transition to hardened seats to increase longevity and reliability. Also this was made possible by advances in machining technology. Lead was added to fuel as a way to up the ani knock index, then we found out how terrible an idea it was to burn lead, so we switched over to ethanol, which was not quite as cheap, but much cleaner and did a better job.
About any gasoline engine made in the last 20 odd years and intended to be sold the US is designed to run on up to 15% ethanol (and honestly it wont effect the older engines either, just make sure your fuel system is rebuilt with viton lines and gaskets, and run more spark advance). The biggest concern with high alcohol contents in gas is that the alcohol will separate and attract water causing corrosion if left to sit static for too long (typically more than 30 days). The easy fix for this is before letting the rig sit treat it with Stabil and top off the tank, making sure to run the engine long enough to ensure the Stabil treated fuel reaches the carb or injectors. This is what I did and never had issues with my motorcycles. I have however heard of some European plastics not handling ethanol well at all. The Italian MFG. of motorcycle tanks Acerbis has problems (or at least used to) with their plastic fuel tanks getting soft and distorting due to corn alcohols. Im not sure if other European MFGs have similar issues.