News Room

To E. or Not to E. - That Is the Question!

Published by STAR Staff on Thursday, December 15, 2016

It seems that Ethanol is again bubbling up both new and standing questions about use and the legalities of. Yes, these issues are again causing debate and concern within our riding community and beyond. To sum up the issues:

1) Ethanol used within fuel is likely to continue to increase in ratio-to-gas Flex Fuel mix.

2) There are legal parameters being proposed about fuel (minimum) limits.

3) There are performance and warranty issues concerning the use of ethanol based Flex Fuel within (most) motorcycles.

Idaho STAR is not taking any position on the legalities, effectiveness, and/or use of ethanol. Instead, this article is designed to help riders understand choices and consequences of using an ethanol based Flex Fuel.

      Quick history lesson to bring everyone up to speed.

E =Ethanol (CH3CH2OH) is a clear, colorless liquid also known as ethyl alcohol or grain alcohol. Ethanol became practical due to the “Clean Air Act” in 1990 that allowed/required gas (aka Gasohol) to be oxygenated to cut carbon monoxide emissions. As a renewable fuel, ethanol is made from various plant-based materials by either (i) a fermentation process of "biomass” (typicallystarch from corn grain), or (ii) a heat/chemical-added process called “thermochemical conversion". Ethanol is mixed with gas at the refinery/terminal to make Flex Fuel and distribute to fueling stations for use in newer passenger automobiles and light-trucks. As you have likely noticed, many fuel stations now supply fuel that contains gas and ethanol mixed. Typical mixtures are E10 (10% ethanol, 90% gasoline), or E15. 

All of this sounds good in theory. However, discussing this with rider advocates, motorcycle service technicians, and riders, there are challenges to be aware of. Some of these include:

1) EPA recommends NOT using Flex Fuel in older than 2001 passenger vehicles, heavy-duty gasoline engines and vehicles, 2-cycle small engine equipment, and on- and off-highway motorcycles.

While the EPA has approved E15 fuels for use in automobiles produced after 2007, additional legislation regarding E15's overall use has been put on hold, pending studies on the impact upon “other” engines. Older vehicle, motorcycle, or small/2-Cycle machinery engines not made to be Flex Fuel compliant is at significant risk. 

2) Flex Fuel decreases energy production. (Yes, ethanol fuel is less efficient than 100% gas.)

Ethanol produces about 34% less energy than the same amount of gasoline. 

An E10 mixture can cost a rider a loss of 3% - 5% of horse power and thus a lower MPG.

3) Flex Fuel decrease fuel efficiency. (Due to decreased energy, vehicles get less MPG.)

Ethanol has a Gasoline Gallon Equivalency (GGE) of 1.5 US gallons (5.7 L; 1.2 imp gal), meaning that it takes 1.5 US gallons of ethanol to produce the same energy as 1.0 gallon of gas. 

Ethanol can make engines more difficult to start in colder and/or wetter climates.

4) Ethanol burns at higher temperatures than gas. 

This can cause over-heating or piston damage in engines not designed to run Flex Fuels,

i.e. motorcycles, small engine machinery (tractors, chain saws, etc.), or antique vehicles.

5) Ethanol is hydrophilic this means that it pulls moisture from the air and bonds with it.  

This happens because water moisture, along with ethanol, will slowly deteriorate the metal parts of the fuel tank and carburetor. This happens because water combined with ethanol separates from gasoline and sinks to the bottom of the tank. This is called “Phase Separation”. 

6) Ethanol is both a great cleaner and is corrosive!


As a solvent, ethanol cleans any/all grunge accumulated within the engine accumulate. In doing so, these dislodged particles then flow into the fuel system causing issues and/or clogs.

      As a drying agent, ethanol disintegrates plastics and rubber and can corrode aluminum and magnesium. 

      As a corrosive, it is most destructive to ferrous metals (containing iron) such as steel. It typically builds up salt deposits and/or gummy varnish deposits.

7) Flex Fuel has a shorter shelf life.

have shown that ethanol based fuel blends deteriorate and spoil within only a few short months. 
It is recommended to replace/fill your flex fuel every few weeks to avoid phase separation.

All of this is especially important if you store your motorcycle over winter months.

Switching gears - what does this mean to you as a rider? (Or, user of vintage vehicles, marine engines, or 2 cycle machinery.)

Some questions to consider:

1) Is an ethanol flex fuel mix appropriate? Check your operators guide to see what fuel (octane and/or flex fuel) is recommended.

2) What happens when using 87 octane E10 gasohol? Over time, water is absorbed from the air and bonded to the ethanol. Phase separation is where water/ethanol bond sinks and causes the engine to run rough, stall, or worse damage fuel system and engine components.

3) How are levels of ethanol really monitored (if at all) by gas stations? How do you really know what ethanol level you’re filling-up with?

EPA’s E15 Misfueling Mitigation Program and the E15 & Flex Fuel Retailer Roadmap (E15 FFRR) Programs

In promoting public awareness of current issues, there are three things you may want to be concerned with regarding the EPA’s E15 Misfueling Mitigation Program (E15 MMP) and the E15 & Flex Fuel Retailer Roadmap (E15 FFRR) programs.

      a) E15 MMP: The EPA is allowing retailers to see E10 fuel from the same pumps/lines as E15. This creates an issue where a rider could end up with as much as a quart of E15 within their tank. Especially potent when a tank may be of only 2.5 gallons, or slightly larger.

      b) E15 FFRR: E10 is continuing it’s progression to E15, E25, and beyond. Most motorcycles are not (yet) designed to function with any level of Flex Fuels.

      c) E15 FFRR: (1) Requires a minimum purchase of 4 gallons and stickers at fuel pumps to state, “Dispensing Less May Violate Federal Law.” (2) Requires stickers on all fuel pumps to state, “Passenger Vehicles Only. Use in other vehicle engines and equipment may violate Federal Law.”

Considering the minimum purchase requirement of 4 gallons, how would you handle these scenarios:

- As many motorcycles do not, or legally cannot, use Flex Fuels, how do you fill up at typical stations?
- If you have a fuel tank that is less than 4 gallons, how would you legally fill-up?

- If wanting to top-off your 2.5 gallon gas container/jug for your chain saw, weed whackers, or other small engine tool, what do you do?

All of these topics pose questions and/or concerns that each rider should consider. Is there a need for more information and performance testing? Should we request legislative action to not limit our (rider) options and resources. Just thought, you may want to consider, ”To E or not to E.”



Anonymous commented on 16-Dec-2016 10:23 AM
Hopefully Trump will slap the cuffs on the EPA because they're out of control.
Jeff McClure commented on 16-Dec-2016 02:42 PM
My 2014 owners manual states that "no" ethanol gasoline is better, but not to exceed 10%. Then I discovered this web site called "" it lists gas stations that have ethanol free gas, by state, and you can copy off the lists, so I now make copies of states I plan on traveling in before leaving on long trips, I also have a station about 2.5 miles away from my house that I always fill up at.l

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