Is ethanol suitable for motorcycles?

E10Most motorcycle riders should steer away from ethanol-blended fuels, at least in the long term.
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) but some countries use 85% or even higher.
E10 is becoming more prevalent throughout Australian service stations and NSW service stations even have to stock a minimum requirement of the fuel.
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 is rated at 95 RON which seems like it could be suitable for bikes that require that higher octane rating.
However, RACQ executive manager technical and safety policy, Steve Spalding, says 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.
Either ask the servo 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.
Some riders believe they are doing the planet, farmers and their hip pocket a service by filling up with ethanol, but that debate is very complex and far from definitive.
We won’t begin to tackle the environmental concerns which are not proven anyway, but we do believe it is not doing your hip pocket any favours, even though E10 is usually a few cents cheaper per litre.
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.
Some outback riders will have noticed servos in the Northern Territory and remote communities selling Opal fuel.
It is a type of fuel developed by BP that prevents petrol sniffers from getting high. Unleaded fuel is banned in these areas.
There is nothing for motorcycle riders to fear from Opal as it has similar properties and performance outcomes to regular ULP (91 RON). There is no evidence to support claims that Opal does any damage to engines that can run on 91 RON.

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