ETHANOL IN GASOLINE: THE PROBLEMS
 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.
Recent-model automobiles have digital fuel injection capable of automatically compensating for this leaning effect of E15 fuel. “Yellowcap” or “Flex-Fuel” vehicles, which make up about four percent of the U.S. auto/light-truck fleet, are able to compensate for fuels containing up to 85 percent alcohol (E85).
 Metal fuel-system parts can corrode as a result of exposure to alcohol. Fuel additives are sold to inhibit this. Solvency of alcohol in certain fuel-system plastics, rubber and seal materials used in older vehicles can lead to softening and swelling. Fuel additives cannot prevent this.
 Alcohol absorbs water from any source (even from the atmosphere). Once alcohol that is dissolved in gasoline has absorbed sufficient water, it can separate from the gasoline and settle to the bottom of the tank. If this separated wateralcohol mixture is drawn into the engine’s fuel-system, the engine will run lean and may misfire or stop running.
14] Some fear that the E15 fuel remaining in the blender pump’s hose and pump, when mistakenly mixed into the small fuel volume of a motorcycle’s or other small engine’s tank, might result in a mixture lean enough to cause engine damage.
To prevent this, EPA will require customers using the E15 blender pump to buy at least four gallons of fuel. This will dilute the fuel that remains in the hose and pump enough to make it harmless to your bike.