Yesterday when I gassed up, the bike took about a 1/2 gallon less than I was expecting, so I decided to calculate my mpg for that tank... 44.5652 miles per US gallon! The best it has ever done! The whole tank was burned at 1,000 feet or less of altitude (commuting) in hot weather (for western Washington - mid 60's in the morning, mid 90's in the afternoon), with humidity in the 40-50% range. I was pretty shocked the mpg was so good given the weather conditions.