Main Motorcycle: 2003 Triumph T100
Join Date: Nov 2005
Location: Waldheim, LA
Other Motorcycle: 2007 M-G Cali Vintage
10% ethanol fuel requires 3% richer tuning to match the performance of pure unleaded; 15% ethanol requires nearly 4.5% enrichening. This is why Bonnevilles seem excessively lean as stock in the USA and why gas mileage is not as good as one might expect. The negatives of ethanol fuels don't stop there, either: Because ethanol is hygroscopic water can be absorbed into your fuel, pooling at the bottom of your fuel tank. This can account for hard-starting, fuel tank rusting, and the formation of aluminum oxides in your intake system (especially carburator float bowls). If pure unleaded is not available, you can reduce the negative effects of ethanol fuels by stabilizing your fuel (I use Seafoam) and closing your fuel tap (if your bike has one) at the conclusion of every ride. These precautions are even more important if your bike will not be used for two weeks or longer.
2003 Bonneville T100 and 2007 Moto Guzzi California Vintage