I have some friends who own a local motorcycle repair shop. Alcohol in gasoline is a frequent topic of discussion. I have heard riders blame all sorts of engine problems on alcohol/gasoline blends. Not once have I seen what I would consider definitive proof that alcohol was at fault. Don't get me wrong, I don't like the fact that we are forced to use gasoline/alcohol blends and I won't go into the political nature of this argument.
That said, the primary threat of blending alcohol in gasoline is corrosion followed by the wear that alcohol causes because it reduces the lubricating ability of gasoline. Back to the motorcycle shop - the biggest problem that I have seen with motorcycles having fuel issue are old gasoline, this is a common problem with: boats, jet skis, generators, and seasonal power equipment such as lawn mowers were they can sit for protracted amounts of time and the gasoline simply goes bad. The second biggest fuel problems come from the gasoline stations themselves - water in their gas tanks. This is not a problem having to do with alcohol in the fuel. It has to do with fuel storage tanks that are subject leaks that let water into the tanks.
True - alcohol bonds easily with water. But it does not suck water through your gas tank or through the gas cap. It does not create water out of gasoline either. There has to be a source of water in the first place and that is usually the gas station where you bought you gas. The best thing that you can do to ensure good quality gasoline is in your tank is to buy fuel only from newer gasoline stations where you can be fairly certain that the tanks are free of water.
Here in Denver, NC we have one station that has had serious issues with water in their gasoline. I once saw a gallon can of their premium gasoline that had over a cup of water in it. In non-alcohol blended gasoline water in the fuel is obvious. It will not mix with the gas and you can see it. In alcohol blended fuels the alcohol can mix with enough water to make the gasoline useless, and you can't see the obvious separation between the gasoline and water. Neither contaminated fuel should be run in any vehicle.
I have three SUV's, a truck, a Wave Runner, a boat, one Harley Dyna, a tractor mower, a zero turn mower, two generators, a string trimmer, and a blower. I have never had a gasoline problem with any of them. This is what I do:
Use a fuel stabilizer such as Sta-Bil in all gasoline that goes into any machine where the gasoline will sit for more than thirty-or sixty days unused. Always buy your gasoline from newer stations that have clean, water-free tanks. Any machine that is being readied for seasonal storage should also have its fuel tank filled to the top. Air has moisture in it; a full gas tank has little to no air, thus no moisture.
Back to the motorcycle shop for a third time. Alcohol blended gasoline seems to have little effect on bikes with carburetors. It can damage gaskets, but I have not seen one where this was the case. If a carburetor is messed up, it is always from old gasoline that has turned to varnish. Corrosion from alcohol blends can score injectors. I have not seen this yet either. Again, the primary issued with a clogged injector is old gasoline. In most cases a couple of tanks of good gas mixed with Seafoam or Techron will clean the injectors.
If you are buying good quality gasoline/alcohol blend you can help reduce the risk of corrosion and wear by using an inexpensive additive such as Marvel Mystery Oil to the gasoline. It's cheap, it's been on the market for decades, and it also helps keep your engine free of carbon deposits. It really does work and it can't hurt anything.
The political alliances that are profiting handsomely from adding alcohol to our motor fuels are pushing for up the percentage of alcohol from 10% to 15%. About all we can do is to try to adapt to a less than ideal fuel supply.
