What fuel are you running?
Is it non corn, or is there 10% corn ethanol added to your region's fuel? Non corn fuel is better.

Maybe try running some Seafoam through your next tank of gas?

 

It most likely is not related to the OP's problem but gas mileage does decrease with cold temperatures. Cold intake air is more dense -> more oxygen per unit volume -> ECM requires more fuel than with warm intake air.

 

i took it to dealer and all they could say was maybe it was the fuel filter i just dont see how the fuel filter would effect it as bad as it is

 

A friend with a tri glide had the same problem. They could not get more than 75 miles from a tank, other than that bike ran fine and plugs didnt look fouled. Dealer fix said it was the pressure regulator not seated properly. Might want to pull fuel pump and take a look.

 

Winter blend gas sucks. I ride year round in NC and mileage always gets worse as the weather gets cold.

 

I had the same prob with my 05. Turned out to be the compression rings were bad. I went from 40 mpg to 20 mpg in about a month. Then went from 88" to 98" and milage went back up to 40 mpg after I got thru playing with the new hp.

 

their adding more and more corn to the fuel now days try running different fuel, no corn.

 

Take it to another shop and have the codes re-read.

 

check the temp sensor in the head. I have an 04 where this sensors goes out about every other year. I have not figured out what happens but i will be getting 39 MPG then i will get 30 to 31 all of a sudden. Change out the sensor and bingo mileage goes back up to 39. I am not sure what causes them to go out, but i can usually tell its happening by the mileage dropping and it will stall when cold for no reason. Have checked wiring and traced it all the way back, would enjoy hearing any suggestions....

 

Where is the temp sensor in the head located and what does it look like?

Thanks!