i have a 1999 flhtcui with a 95 inch stroker, theres tons of pull, i pulled me , my wife and a trailer to sturgis and back from uper canada..depending on the wind , road grade, air temp and octane of the fuel and driving speed i got all sorts of varying results..the best was over 300km to a 18 liter tank the worst was 100km to the same tank but we were pushing a nasty head wind...id say 40 to 45mpg is about right though, as long as i didint speed..for the fun of it change your plugs and clean the air filter o see it it helps...my round town milage suchs...to much starting and stoping...