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Ethanol Motorcycle Fuel information and advice. Don't hit the road without it!

Find out how Ethanol Motorcycle Fuel can affect your ride E10 ethanol, which is 10% ethanol blended with gasoline, can be used as a fuel alternative for your motorcycle (or other collector vehicle) with little to no problems. E10 ethanol based gasoline is what most of us have been using in our fuel tanks regularly for the past two decades and in most cases without knowing it.

When filling your motorcycle up you may have noticed a sticker on the gas pumps that says "Gasolines May Contain Bio-Based Oxygenators (Ethanol)." This just means you are getting E10 ethanol gasoline. If you have a relatively new motorcycle or have rebuilt the fuel system in your classic motorcycle recently then you should have had few if any problems running it on E10 ethanol gasoline. If you have not rebuilt the fuel system on your older motorcycle then you may want to look into rebuilding it before running a lot of E10 ethanol gasoline. The use of E85 ethanol gasoline in any motorcycle is not recommended at all unless it has been properly converted to run on flex-fuel.

What is Ethanol?

Ethanol Motorcycle Fuel

Ethanol is an alcohol made from corn, sugar cane and other grains. Ethanol is used as an oxygenate in ethanol motorcycle fuels. It promotes clear burning and helps increase octane. One good thing (but in excess potentially a bad thing) it does is absorb water which means it will help prevent fuel lines from freezing and it will limit the corrosion caused by water in the tank.

The ethanol in E10 is also a solvent that will loosen sludge, varnish and dirt that has built up in your fuel tank. It promotes clear burning and helps increase octane. One side effect of ethanol is that it absorbs water. This means it will help prevent fuel lines from freezing and help limit the corrosion caused by water in the tank.

There are two types of Ethanol motorcycle fuels currently available in the US. One is relatively safe for all motorcycles and the other is not unless your motorcycle specifically states it is designed to run on flex fuels. The other type of ethanol blended gasoline is known as E85 which is 85% ethanol. E85 is not a safe alternative for any motorcycle unless it is designated as a "flex-fuel" vehicle.

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What does it mean to my motorcycle?

There are certain potential hazards and unwanted side effects associated with using E10 in your motorcycle. Your vehicle will consume more fuel especially if you use E85 which officially and generally stated by the ethanol industry as a 25% to 30% drop. This is because ethanol contains less energy than gasoline despite a higher natural octane number. The fact that it does help loosen sludge in your fuel tank can cause problems with clogged lines and filters as well as block carburetor jets and fuel injectors. After all those loosened particles have to go somewhere.

Be careful if you don't ride a lot. Using ethanol motorcycle fuel in bikes that will be stored for lengthy periods of time can be troublesome. The fact that ethanol motorcycle fuel can absorb some water is beneficial but there is a maximum to what it will absorb. Large amounts of condensation will induce the ethanol and water to separate inducing the water to gravitate to the bottom of the tank where the fuel pickup is located.

Make certain, no matter what type of gas is used, that if you are going to store your motorcycle for a prolonged period of time that you take precautions. It is advisable to either completely empty your tank or fill it all the way up to help reduce potential damage to your gas tank. Please be aware that there are many other elements involved in properly preparing a vehicle for storage other than just the fuel in the gas tank. Also don't forget to add gas stabilizer to your gas should you decide to leave gas in your tank.

Another potentially serious problem with ethanol is that it can be incompatible with older rubber compounds. Also in higher concentrations it can cause corrosion to steel and aluminum that is a part of older motorcycle fuel systems.

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4 things you can do to reduce the damage of E10 ethanol

If your older motorcycle hasn't been rebuilt/restored in the last 10 to 15 years you should really think about:

  • Replacing all gaskets, seals and rubber fuel lines.
  • Replacing fuel filters and/or screens or at the very least clean them.
  • Pull the fuel tank, drain it and clean it out to remove dirt and sludge before the ethanol can loosen it up.
  • To combat corrosion you can use a gas tank sealer impervious to ethanol motorcycle fuel.

This should certainly be done before filling up and starting your motorcycle if it has been sitting for a long time whether it was prepared properly or not.

What about higher concentrations of ethanol like E85?

E85 Icon

E85 is a mix of 85 percent ethanol and 15 percent gasoline. Unless your motorcycle is designated as a "flex-fuel" vehicle you should not use E85. If manufacturers are making E85 motorcycle, they are definately keeping it quiet, but they are probably coming soon.  If you run E85 ethanol motorcycle fuel in bikes that are designed for gasoline, then your motorcycle may be severely damaged. It can cause damage to seals and hoses along with causing corrosion throughout the fuel system. It can also wash lubrication off the engine's cylinder walls. The hydroxyl group on the ethanol molecule is an extremely weak acid, but it can enhance corrosion for some natural materials.

For ethanol contaminated with larger amounts of water (i.e., approximately 11% water, 89% ethanol), considerable engine wear will occur. This wear is especially harsh during times while the engine is heating up to normal operating temperatures. Just after starting the engine low temperature partial combustion of the water-contaminated ethanol mixture takes place and causes engine wear. This wear, caused by water-contaminated E85, is the result of the combustion process of ethanol, water, and gasoline producing considerable amounts of formic acid (also known as methanoic acid). In addition to the production of formic acid occurring for water-contaminated E85, smaller amounts of acetaldehyde and acetic acid are also formed for water-contaminated ethanol combustion. Of these partial combustion products, formic acid is responsible for the majority of the rapid increase in engine wear.

Engines specifically designed for ethanol motorcycle flex fuels employ soft nitride coatings on their internal metal parts to provide resistance to formic acid wear in the event of water contamination of E85 fuel. Also, the use of lubricant oil (motor oil) containing an acid neutralizer is necessary to prevent the damage of oil-lubricated engine parts in the event of water contamination of fuel. Since older cars are not protected from formic acid the use of E85 is not recommended.

Concerns of the AMA

The American Motorcyclist Association has expressed concern over some proposals by the state of Minnesota to allow gas stations to increase the levels of ethanol in the fuel they sell.

Even though the current proposal comes from Minnesota, the AMA says that an EPA waiver would open the door to the sale of 20 percent ethanol blends across the coutry, while not requiring evaluation of the long-term effects.

"The AMA supports the use of cleaner-burning fuels, but we are concerned about premature engine damage or failure while a bike is being ridden on a highway if the allowable level of ethanol is raised to 20 percent," said Imre Szauter, AMA legislative affairs specialist.

It's worth keeping an eye on.  Szauter said that "Until studies show that a 20 percent ethanol blend won't damage motorcycle or ATV engines, and won't make motorcycles emit more nitrogen oxides than are allowed by the EPA, the AMA can't support the Minnesota proposal."

For more information about ethanol motorcycle fuel, visit which has also released a report that studied the impacts of ethanol blends in various types of engines.

For more information about fuel savers for all vehicles, click here.


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