By Chad de Alva


Gasoline is a wonderful thing. In roughly a minute, you can dispense enough gasoline from most gas station fuel pumps to fill the tank on most motorcycles – and that’s all the fuel your bike needs for hours of riding enjoyment. Gas stations are everywhere, and most riders have fueled gasoline powered vehicles so many times that the process is about as routine as brushing your teeth. Yet changes are in store for the fuel that will be available at gas stations in the United States over the coming months, and uninformed riders who blindly assume that the fuel they’re dispensing into their bikes is the best fuel for the job, may find themselves in for quite the surprise. That’s why now is a great time to get up to speed on fuels you may see at the pump, and the best practices for acquiring and storing gasoline. The US Government has decided to allow the sale of what’s called winter fuel, and a type of fuel called E15 this summer.


Normally, winter fuel is only sold in certain regions of the country, and its lower boiling point and higher vapor pressure help with cold weather starting. E15 refers to fuel that contains 15% ethanol, and it’s also not normally sold between June and September. Most gasoline found in the United States is E10, which is fuel that contains 10% ethanol. To make things confusing, labeling at gas stations is inconsistent and unclear. For example, did you know that 88-Octane fuel in some regions is actually E15? Have you ever purchased fuel from a pump with no label declaring the ethanol content, or no label indicating whether the fuel you’re buying has no ethanol, or is ethanol free?

So why does any of this matter? Ethanol is less energy-dense than gasoline, and increasing the percentage of ethanol in a given volume of gasoline will have a number of impacts on how a motor runs, and it increases the potential to damage your bike. It’s also illegal to use E15 fuel in motorcycles, boats, and small engines like lawn mowers and chain saws. The use of E15 can also void your bike’s warranty.


To understand the implications of winter fuel and ethanol fuels in motorcycles, I reached out to Chris Real. Chris has spent his entire career in the lubrication, fuel, and specialty transportation industries. He’s the owner of DPS Technical, a company that performs vehicle and component testing for many motorcycle manufacturers and government agencies, and he’s also a lifelong motorcyclist – the perfect Subject Matter Expert in other words.


Using any percentage of ethanol in fuel has the potential to cause negative impacts. Ethanol fuels love to absorb water, and water in your fuel system can cause accelerated component wear, corrosion, and it can cause deposits to form. Gasoline typically has a significant volumetric expansion when it gets hot, and when it cools, the contraction of fuel draws air into the tank. If it’s humid, the water vapor in the air condenses as the system continues to cool, and now you have water in your fuel. Water is not something you want in your fuel system – clogging, corrosion, and deposit formation are all possible. Deposits can clog both carburetor jets and injector nozzles. Corrosion harms fuel system components, and water molecules can restrict fuel flow. While one fill up on ethanol fuel isn’t likely to ruin your bike, regular use of ethanol fuels can make these problems more likely to occur.

Even if water doesn’t form in your tank, winter fuel and ethanol fuel can still impact how your bike rides. The lower energy density of ethanol fuels means that bikes will run lean, make less power, and have reduced fuel economy. There is also a greater chance of boiling fuel which can lead to fuel geysering. Fuel expands as it gets hot, and a bike running winter fuel or ethanol fuel on a warm day at altitude can see its fuel boil quite easily. Hot fuel is less energy dense than ambient temperature fuel, which poses problems for both fuel injected and carbureted bikes. Modern adventure bikes have more sophisticated fuel injection systems, so the most noticeable impact will be reduced fuel economy. Simple EFI dual sport bikes, dirt bikes and trail bikes will likely see a reduction in fuel economy and a loss of power on warm days. Lean running conditions are also possible. Carbureted bikes are at the greatest risk here, as carb settings are fixed – unless you’re in the habit of re-jetting mid ride. It’s important to remember that if your bike starts running differently, it may be a result of the fuel in the bike. So before you start replacing injectors, computers, and other expensive bits to try to solve the problem, try some ethanol-free fuel.


Boiling fuel can lead to some very scary situations. There are multiple videos floating around on the internet of some poor soul opening the tank on their bike when the fuel is obviously boiling. As soon as this rider cracks the fuel tank cap open, a geyser of fuel sprays out of the bike soaking the rider. Given the right conditions, this fuel spraying out of the tank could lead to a fire. Fuel geysering as a result of modern fuels has become such a hazard, that many federal jobs are now incorporating fuel geysering training into their education programs. If you hear your bike rumbling or hissing when you stop or you can see your fuel boiling, wait until the fuel cools before opening the fill cap.

Now that we’ve covered the implications of using winter and ethanol fuels in bikes, let’s cover the best practices for acquiring and storing fuel. The easiest solution is to simply purchase ethanol-free gasoline, and PURE-GAS.ORG is a great resource for finding ethanol-free gas pumps near you. If getting ethanol-free gasoline isn’t feasible, the following practices for storing ethanol fuels will help minimize the chances of damage to your bike(s). Ethanol fuels have a shelf life of two to three months, whereas non ethanol fuels are rated for six months. Using a fuel additive to store ethanol fuel certainly helps, and keeping your bike’s tank topped off will limit space available for air to precipitate water into your fuel. Empty the bowl(s) on carbed bikes when parking them. When storing fuel, keep it out of the sun! UV can absolutely destroy fuel, and it took only a few hours of sun exposure to separate some race gas I left out in the sun.

Here are the key points to remember when acquiring and storing fuel:

  • Check your manual for recommended fuels. If ethanol fuel isn’t recommended, find an ethanol-free pump, or you can obtain prepackaged ethanol-free fuel in stores.

  • Check for labels at the pump. If it isn’t explicitly labeled as Ethanol-Free or Non-Ethanol, it’s most likely E10.

  • 88 Octane pumps may dispense E15 fuel.

  • Never ever use E85! That’s 85% ethanol fuel.

  • Empty carb bowls, and store bikes with a full tank of stabilized fuel.

  • Keep fuel out of the sun – that includes parking your bike with a transparent tank out of the sun whenever possible.

  • Avoid fueling with any system where you’re drawing fuel from the bottom of the dispensing container.

  • Any water in fuel will settle to the bottom of the container and a klunker, or dip tube will pull that water in your bike.


Here are the key points to be mindful of when riding this summer:

  • Expect less fuel economy, less power, and potential lean conditions when using ethanol or winter fuels.

  • Beware of fuel boiling and fuel geysering.

  • When opening the fuel cap at the gas station, keep your visor down and stand off to the side in case a geyser does occour.

  • Don’t fill your tank right before you park your bike. This may cause fuel to fill your bike’s vapor recovery system, or plug the venting system.

A little extra attention to detail is all it takes to have a great time riding this summer. Consult your bike owner’s manual(s) for recommendations on fuel. If the manual says E10 is good to go, then be mindful of how you store the fuel. Ethanol-free gas is always a great option, but don’t assume you’ll always be able to find an ethanol-free pump. Remember that prepackaged ethanol-free fuel can be purchased in stores if needed. Keep all fuel out of the sun and use a stabilizer if you’re working with ethanol fuels. When you’re out riding, plan for less range, and keep an ear and an eye out for fuel boiling. Fuel showers are not something you need in your life. Bear these key points in mind, and you’ll have a great summer riding season.




This story was originally published in Issue 82