I am leaning toward this I have a 99xlh 883 w/ s/ecams, santee 45's se a/c carb has been rejetted to match. I can't remember getting worse than 40 mpg. closer to 50 on the road.

 

yea idk what the problem is but I get atleast 100 miles per tank and thats hard riding with enough gas left in the tank in case there isn't any station near by