Flexible Fuel Motorcycles

Ford Motor Company has been making a lot of announcements recently about how it is pushing development of flexible fuel vehicles and building a flexible fuel infrastructure so those vehicles can fill up, which primarily means with E85, so I started to wonder about motorcycles. What fuel options does a biker have?

If you're not familiar with the term "flexible fuel," it means a gasoline engine with the ability to run on more than one fuel. Although natural gas is sometimes the other option, the usual secondary fuel is ethanol in varying concentrations. The amount of ethanol is indicated by a number which is the percentage of ethanol in the gas/ethanol mix. Ethanol is usually offered in either of two concentrations, E10 or E85. E10, 10% ethanol, is widely available and most vehicles built after 1980 can just use it like gasoline without any modifications. Mileage will drop slightly but everything else will be normal. Motorcycles can also use E10 without any changes, but check your owner's manual to be sure. There may be a company that does not allow it.

E85 is a different animal. At that concentration, the fuel becomes corrosive to regular fuel lines and adjustments must be made to the ignition timing and fuel injection to be sure the fuel burns properly. All of the auto manufacturers are producing a lot more of these vehicles and sensors in the exhaust automatically pick up the presence of E85 and adjust accordingly.

Every manufacturer building this capability into its vehicles seems to tout the fact but I haven't heard of any motorcycle manufacturers producing these vehicles yet. Doing some digging I came up empty but that doesn't mean E85 capable motorcycles do not exist. I'm not sure there is any real demand for them but it would be good to know if they are out there. Do any of you know?


  1. says

    I’d also love to know if my suzuki can take E85, etc. If not what can I do modify it so that E85 would be acceptable. Also, I’ve been looking for E85 pumps or even E10 but can’t find. Any help?


  2. Frank says

    When I was crossing the country through Nebraska, amongst all the miles and miles of corn, I came across a yellow handled fuel pump next to my $3 gas pump. It was 99 octane, and cost about a buck. It was E85. It only stands to reason that the farmers of this country would pass on petroleum and fuel themselves. I almost reached for it, when I saw the giant warning label to “consult your manufacturer before using this fuel.” Damn. Somehow i doubt my ’77 goldwing was up for the challenge of properly digesting this stuff!

  3. says

    I posted the above article at http://e85forum.com . I have been riding an E85-powered Suzuki GS500 for a couple of years. I did need to rejet significantly, but made no other changes to the fuel system, and have had no fuel-system problems. The motorcycle is not “Flex-Fuel”, since it would run overly rich on plain gasoline. To be truly “Flex-Fuel”, you would need to use a programmable injection system like MegaSquirt.

  4. ACP says

    I have been told that the BMW R1200 GS / Adventure model can safely adjust to and run on E85. Can anybody confirm this?

  5. says

    The E85forum.com website is frequented by people who (ahem) think for themselves: racers, bio-fuel advocates, tinkerers, and a few Genuine Characters. The information there is not “safe” in the corporate sense, but can give you some good background on what other people have tried with E-85 and various vehicles.

    Regarding whether the Bimmer (or any bike) can handle E-85: it’s fairly simple to test your bike for its ability to ajdust the air/fuel mixture for E-85. You can try mixing E-85 and gasoline, in increasing amounts, until your sparkplugs turn white. That should be a hint that your ECU is no-longer able to keep the air/fuel mixture in stoich.

    I’d recommend starting with a 1:2 mixture of E-85 with regular unleaded, and trying 1:1 and even 2:1. I’d be surprised if you can’t get to a 1:1 mixture, but depending on temp. and altitude, “your mileage may vary.”

    Kneesliders will be interested in the 105+ octane of E-85: if you want a dedicated race bike, it’s time to visit your local machinist for some domed pistons. You may want to change-out your front sprocket, or the friction zone will get a tad short.

    Shiny side up!