From the same site:
"Motorcycles and ethanol fuel. Two things that do not go great together. owning and driving a motorcycles is a seasonal thing. Our motorcycles are usually our second or third means of transportation. Meaning they are not ridden every day. sometimes they are not ridden for weeks or months at a time. And time is the enemy of carbs or fuel injections systems. When ethanol fuel is in the mix. Ethanol is the governments great idea to make a fuel source from plants. Like corn or sugar cane. It is mixed in our fuels in different ratios up to 15% . This means gas can have up to 15% ethanol in the mix with gasoline. This is not a problem for machines that go through multiple tanks of gas a week. The fuel is turned over regularly and doesn’t sit for more than a few days at a time. Our motorcycles tend to have a lot more down time than automobiles and that is where things can go bad quickly.
Unlike gasoline, ethanol is hygroscopic, meaning that it will attract water from the air, which is absorbed into the gas. Lowering the octane of the fuel and making the engine have to work harder. This is also not a good thing for a motorcycles carburetor or a fuel injection system. having water bonded with ethanol starts a reaction inside the carbs and fuel tank. The ethanol literally starts growing and eating the parts inside the motorcycle. It creates a gum like substance that will block up a fuel injector or a jet in 2 seconds. Even the fuel that is in the tank will grow and block up fuel filters. This gum can even damage the engine or head assy in your motorcycle. So what can you do to prevent this kind of damage to your motorcycle? depending on your state, you can still find gasoline that is free of ethanol. This is the best way to prevent the problems that come with its use.
If you are like me and come from California. That mandates all fuel to be mixed. You have to start using a fuel stabilizer. There are many different brands of fuel stabilizers on the market. Most all of them will get the job done. The one we use is Star Tron. It is a enzyme fuel treatment. It uses enzyme to control the ethanol in the system and to help the combustion of the gasoline. I recommend it to all my customers and it really helps to prevent costly carb repairs down the road."