‘Bad’ ethanol forced on motorcycles

Dirty fuel - ethanol fuel economy

Governments are continuing to push ethanol in fuel, despite it not being suitable for most motorcycles and the US Environmental Protection Agency calling for a cutback in its availability.

The latest government to consider an ethanol mandate is Queensland which has shown bipartisan support in the erroneous notion it is good for the environment and fuel prices.

While the odd dose of ethanol is ok for most bikes and fine for modern BMWs and American bikes on a more regular basis, it may cause long-term damage to most others.

And while ethanol is cheaper, it is also less efficient and, in the long-run, is not any more economical considering the engine damage it may cause.

Mandating that service stations stock a certain amount of ethanol-blended fuel is purely a political decision to appear environmentally friendly and aid farmers who probably should have switched to other crops years ago when the demand for sugar declined.

Ethanol is a type of alcohol produced by fermentation of crops such as sugarcane or grain. In Australia, ethanol content in unleaded fuel is limited to 10% (E10) but some countries use 85% or even higher in South America.

E10 is becoming more prevalent throughout Australian service stations and Queensland looks like following NSW where service stations have to stock a minimum requirement of the fuel.

CFMoto 650NK fuel filler - ethanol

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.

But one of the confusing things for riders is the octane rating. (Octane is a measure of a fuel’s ability to resist engine knocking or pinging which is an uncontrolled burn in the engine that can cause damage. Higher octane fuels resist knocking.)

Most E10 in Australia is rated at 95 RON which seems like it could be suitable for bikes that require that higher octane rating. (In America it has a lot lower RON ratings as their highest RON fuel is only 91.)

RACQ executive manager technical and safety policy, Steve Spalding, warns that ethanol-blended, higher-octane fuels may not necessarily meet the correct fuel requirements for a vehicle designated to run on PULP.

While the RON may be high enough, there is another property in fuel, called Motor Octane Number (MON), which is rarely specified on the bowser.

MON is usually about 10 numbers lower than RON, so a MON of 85 would be ok for a bike rated at 95 RON.

However, ethanol fuels have much lower MON numbers than their RON which could be too low for your bike.

Avoid filling your motorcycle tank with ethanol fuel
Ethanol fuel is fine for Harleys

Either ask the service/gas station for the MON rating or fill up non-ethanol premium unleaded fuel of 95 RON or higher.

It is always best to have a higher octane rating than a lower one even though modern engine management systems have knock sensors that can handle lower octane.

If there is no choice but to fill up with ethanol fuel, make sure your next fill is with a high-octane fuel.

Ethanol supporters say it lowers gas/fuel prices, furthers energy security by reducing reliance on foreign oil, and revitalises the rural community. However, even those debates are far from definitive and the environmental argument is far from proven.

But mainly it is not doing your hip pocket any favours, even though E10 is usually a few cents cheaper.

There is about 3% less energy content in a litre of E10 compared with unleaded fuel which means your engine performance and fuel economy will be 3% worse, or to put it another way, your range will be limited by 3%.

The price of E10 would need to be at least 3% less than ULP for riders to even break even on the fill. And then there is the long-term damage it could do to your engine.

The U.S. Environmental Protection Agency has acknowledged that ethanol can damage motorcycle engines and has proposed a cutback in its availability, not a mandate as Queensland wants.

The US agency says ethanol-blended fuels increase exhaust temperatures which can cause component failure.


  1. Geewiz, quite by accident, (as it was the only fuel in the town, and I didn’t wanna risk not making it to the next town, so I pumped $10, of 100 plus ethanol blended fuel from a United station, and indeed I was worried, for what then, was a six month old Triumph 1600 thunderbird. As I climbed the nearby foothills, my mind was put at rest, This go juice had the bird pull even harder, and the awesome crisp note that was expelled from the pipes was pure music to my ears. Yes the bird now pulled even harder than a thirteen year old with his first playboy.
    Not so sure about Triumph and any possible warranty claim in the future, I flicked Triumph UK a quick email, about the predicament, that had found myself in, and the use of ethanol. No problem there with Triumph.
    Having noted a handy increase in torque, and heading off on a extended tour of FNQ, with a trailer, I once again turned to the United 100plus. well well well, it constantly returned 50k’s extra per tank. Over BP 98 and Caltex 98

    1. Hi Mark,
      I’m not a big advocate of fuel additives, however Motorex’s Fuel Stabiliser is good to prevent the affects of storing your bike for a long time, combatting “dirty” and low-grade fuel and, I believe, ethanol.

  2. When we got the change to unleaded there was a lot of misinformation {lies]
    about what would run on the stuff. Anything from any government agency
    should be treated with suspicion

  3. Mark. You said ethanol is fine for BMWs. The attached picture is of the fuel pump mount (old and new) from a ’93 K75 I have recently purchased. Let this be a warning to others: Stay away from ethanol.

  4. I am a total cynic and smell a large rat in relation to Katter’s party and the ethanol push! Perhaps those of us on Jap bikes can clog up the city one Saturday to make a point…. everybody else seems to be doing it of late !

    1. Mark , you have hit the nail on the head. Keeping Mad as Katter party , keeping them happy , so they can get things through the parliment. Its also the “Northern Australia” Slush Fund (Building a coal mine/railway/ port ) that nobody will finance ?

  5. I own a 2003 CBR600RR. I only run ULP 91RON (non ethanol). I would say in the article if you happen to use E10 in your bike, make sure the next fill up is with what your owners manual recommends. Too many time’s I’ve had arguments with people who swear that “premium” 98 is better than regular 91. However it only benefits vehicles that it is designed for.

  6. Most ethanol produced in Australia is made from wheat, not sugarcane. There’s a strong ethical argument that we shouldn’t be using food to power vehicles when food is in such short supply in large parts of the world.
    Ethanol fuels should never be used in two-strokes as its lower density will provide a leaner mixture at full throttle – the result will be holed pistons.
    Some fuel outlets in Victoria are now selling E85. It’s the fuel used by V8 race cars now but it was a PR decision by the Supercars to keep environmentalists distracted. I agree with Motorcyclewriter that it’s best avoided and the push for it is political, not environmental. It certainly isn’t being driven by engineering.

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