For the first time, America’s Environmental Protection Agency has publicly admitted that ethyl alcohol (ethanol) content in petrol can damage motorcycle engines by raising exhaust temperatures and causing component failures.
Fuel with a five-per-cent ethanol content (E5) is already available on UK forecourts and E10 petrol is imminent, as the European Union’s push towards tree-kissing renewable energy continues. In the US, even more controversial E15 fuel is also on sale. Past concerns related to ethanol’s effect on older classic motorcycles but there are now issues with modern bikes too.
This EPA admission has emerged in a fuel-labelling rule proposal by the US Federal Trade Commission. It recognises that ethanol leans off the air/fuel ratio, which can lead to increased exhaust gas temperatures. The immediate consequence of this is potential damage to emission-control catalytic converters. But a worst-case scenario, particularly for E15 fuel, is engine failure through overheating. The EPA also notes that ethanol can cause materials compatibility problems, which may result in other component malfunctions.