all epa compliant engines produced for at least the last 4 years are designed for 10% ethanol since its required to be 10% in quite a few states
in fact the number ONE reason for ox sensors on our engines is that it totally takes care of the ethanol issue - within the limits of the software that is
to
Someone feel free to correct me if I am wrong, but I don't think that is entirely true. While most (automotive) engines do in fact address the alcohol issue, HD's through 2009 still use O2 sensors to set an AFR (and not lambda) which is designed to deliver 14.7 AFR (not the most efficient burn rate for 10% alcohol). Exhaust emmissions may meet standards, but performance certainly does not. The 2010 baggers have transitioned to "lambda" systems which does adjust for gas or alcohol, but the other 2010 models still use AFR based on 14.7 to the best of my knowledge. So, HD is headed in the same direction as auto makers, but isn't quite there yet (except on 2010 baggers).
jimbob