First off there is no benefit to running premium gas in an engine that is not designed to run on premium. The only thing it does is separate you from a little more of your money at the pump, but as always, it's your money to waste.
Second, there is not one single good reason to burn ethanol in anything. It does keep US from importing any more oil than we have to and it lines the pockets of the farmers growing corn.
On the other hand, "because ethanol contains one-third less energy per gallon than gasoline, adding ethanol to gasoline leans out the fuel-air mixture, possibly enough to cause damage. Several manufacturers of small engines have said they will not honor warranties if fuels containing more than 10 percent ethanol are used."
Studies have shown that a pound of ethanol produces 30 percent fewer BTUs of heat than a pound of gasoline. This decreases mileage by the percentage of ethanol added to gasoline. So, E10 mileage is 3 percent less than that of regular unleaded gasoline.
Ethanol related problems for motorcyclists, include:
- Exposure to alcohol can rust metal fuel-system part and warp or otherwise damage parts of rubber, plastic, and other sealing materials.
- Ethanol soaks up water from everything, including air. Once alcohol in gasoline has soaked up enough water, it causes phase separation and water contamination.
- Fuel has a shorter shelf life
- Creates engine deposits
Every motorcycle mechanic I know, including myself, will argue with you about the damage ethanol does to petcocks, fuel lines, fuel pumps, rubber carb parts and corrosion to metal parts in the system.
One more problem I'm starting to see more of is with plastic atv fuel tanks. The petcocks are attached to the tank with two metal screws that are screwed into brass inserts in the bottom of the tank. After a few years the screws get so corroded in the inserts that they won't come out without twisting the insert out of the bottom of the tank. Then all you have is a $300 piece of junk plastic.
Ethanol serves no useful purpose and it's time to feed the corn to the cows and get it the hell out of gasoline.