Steer clear of ethanol in motorcycles

Avoid filling your motorcycle tank with ethanol fuel

MotorbikeWriter has frequently suggested riders steer clear of using ethanol fuel in their motorcycles and the U.S. Environmental Protection Agency agrees that it can damage motorcycle engines.

The US agency says ethanol-blended fuels increase exhaust temperatures which can cause component failure. It has proposed a cutback in its availability.

Ethanol is a type of alcohol produced by fermentation of sugarcane or grain. In Australia, ethanol content in unleaded fuel is limited to 10% (E10), the US it’s 15% but some countries use 85% or even higher.

Avoid filling your motorcycle with ethanol fuel
Cruiser & Trike editor Mick Withers chooses to fill with premium fuel

E10 is becoming more prevalent throughout Australian service stations and NSW service stations even have to stock a minimum requirement of the fuel which means that there is no alternative at some NSW servos.

According to the Federal Chamber of Automotive Industries, only post-1986 bikes and ATVs made by BMW, Harley, Polaris and Victory can safely use E10. No Japanese bikes and no Piaggio products can use it. The FCAI doesn’t mention other brands, but it can be assumed ethanol blends are not suitable.

Ethanol doesn’t work with carburettors or mechanical fuel injection. It is also a solvent which attacks metallic and rubber-based fuel lines, and has an affinity to water that can cause steel fuel tanks to rust.

For some time the American Motorcyclist Association has been fighting the distribution of E15 fuel blends in an effort to protect motorcycle and all-terrain vehicles from the damage that ethanol causes. It has applauded the EPA’s decision to roll back the requirement for wider distribution and use of E15 under its Renewable Fuel Standard.

According to the EPA, ethanol makes engines run leaner (with a higher air to fuel ratio) which can lead to increased exhaust gas temperatures. It ays that could gradually destroy emission control hardware and performance, possibly causing catalyst failure. Ethanol can also cause “materials compatibility issues”, which may lead to other component failures.

Riders should also be aware that the higher octane rating on some ethanol fuels may be misleading. For more information, read this.

13 Comments

  1. I think anyone who has been using ethanol fuel in their bike long-term should, as a matter of courtesy, mention the fact when selling. That way the buyer can decide for themselves if they should inherit whatever problems may arise. If you’re so convinced it does no damage then it shouldn’t be a problem huh? Good luck.

  2. Hmmmm, yawn, heard and read this stuff so many times, even got sucked into believing it.
    Until i was left stranded, late at night with not enough fuel to make it to the next town with BP 98. So I did a splash and dash, 100 octane liberty 10 litres only. Well suprise suprise, more grunt, more top end.
    So i started a comparison with the trusty iphone app vehical.
    Over 60,000k,s of comparisons between liberty 100 BP 98 95 CALTEX 98 95 and mobil 98 95 solo, two up, and towing a tour trailer.
    The liberty 100 stuff always returned an extra 50k’s to the tank. So impressed with the fuel when on long haul tours with trailer i will carry up to 40ltr extra fuel to make sure the Triumph thunderbird has enough of it favorite go juice.
    However i never leave this fuel in the tank when its parked up for more than 1 day, BP 98 or Caltex 98 is the order of the day.

  3. Steel tanks may be less problematic with ethanol fuels than Polyamide 6 or Nylon 6 based ones (ie, the plastic ones). As Rick mentioned, ethanol is hygroscopic and absorbs (perhaps more correctly, bonds with water). The ‘plastic’ tanks can then absorb the wet ethanol and grow in size, which can make it a real bugger to get your tank to fit if you take it off. Apparently Ducati lost a class action suit for this problem.

    The whole ethanol industry has become a dodgy environmental and political problem too as food production is being replaced with plants for ethanol production.

  4. I’m a qualified motorcycle technician with over 35 years in the industry.
    The fact of whether your bike is listed as “suitable” ( read tolerant ) for e10 is only part of the story. So your bike MAY have upgraded fuel lines and non corrosive fittings etc but the bigger issue I see with it is it’s hygroscopic nature. In fact it can and often does absorb 50 times more moisture than conventional non alcohol fuels. Because of this, the shelf life is very low. 90 days is the maximum recommended shelf life under “ideal” conditions and significantly less in humid environments (2-4 weeks really) and as bike riders often lay up their bikes for periods longer than this in normal use, water contamination and “phase separation” are common issues. ( phase separation is when the ethanol deficient petrol and ethanol rich water mixture separate ) When this happens, one of the many effects is a significant drop in octane rating. There’s more to it, but personally I won’t run it in anything I own.

  5. I have a Honda dated 2011 and the owner’s manual says E10 is OK. So do I take advice from the engineers who designed the motor or FCAI ?

    1. Oldie – my owners manual(2010 Suzuki V-Strom) indicates that the bike can run on practically anything flammable, but a check on Suzuki website essentially says “just because you can, doesn’t mean it is a good idea, please don’t” (like poking yourself in the eye with a fork).

      My feeling is that the owners manual was saying “if you are stuck, these are your options”, Suzuki website meanwhile is based on “we won’t be held liable for you doing it”.

      Honda seems to be saying something similar: http://www.hondampe.com.au/repository/about_honda/faq/general.aspx#9
      “…
      E10 ethanol fuel can be used with Honda Marine and Power Equipment, and also motorcycles produced after 1990, although it is not recommended. Â
      …”

  6. I got stuck with a tank full of blended fuel one day due to the pump not advertising it was an E10 product. As I was leaving I noticed a small flag waving in the wind with the E10 notice for the fuel I had just bought. My V-Star hated it and ran like a bag of shit until I could cut it with decent fuel. I also found that Shell 98 is not suitable for carburetored bikes and cars as it is blended for use in Fuel Injected engines. My bike also hates that stuff.

  7. I used one tank of E-10 at a Caltex servo in NSW and then ran into stuttering when the fuel went low. Continued until cleaned out. No more ethanol for me. NSW Government mandates E-10 sales without realising consequences.

  8. Seeing as my motorcycle has an inline water-cooled 4 cyclinder engine – just like a car – I can’t see how ethanol would be any worse for my engine than for the millions of car engines currently using it.

    I don’t have an issue with using E10. My only concession is that I don’t leave the bike standing with E10 in it. Funnily enough, some of my best economy has been when using E10.

    1. Not sure how you got better fuel economy. E10 is 3% less efficient than the same RON of ULP. Perhaps you are comparing 95 E10 with 91 ULP. Also, comparing fuel economy in real-world situations is difficult.

      1. I agree, Mark. I’ve logged my fuel consumption figures for every tank for the last decade or more. Other factors appear to influence fuel consumption much more than octane rating.

        However, I’ll go back to my point that my motorcycle engine is a car engine. Water cooled. Inline 4. How can E10 be bad for my motorcycle, but not be bad for car engines? Most modern engines are getting at least a quarter of a million km life, and ethanol seems to be present in more and more fuels. Take a look at regular BP ULP, as an example, and see the warning written on the bowzer.

  9. I rarely use E10 fuel but I’ve just been convinced to only use premium , even at current prices its still cheaper than repairing a motor etc . Thanks for the warning .

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