I just noticed on my '09 FXDL that it has a remaining fuel function in the speedo. Does anyone know how this number is calculated? Is it a fixed number or does it change based on your riding habits?

 

Its a reference point calculated by the gods in Milwaukee. It means nothing in the real world. Figure on refueling every 150 miles and you wont have to worry about it. Its only there to give you something to worry about when you should be paying attention to the road.

 

It calculates the remaining miles till empty based on the average MPG on the previous 30 or so miles your drove.

 

mine seems to adjust as riding

 

I don't seem to have that particular function,or it's not enabled,or I just don't know where it is,or do the '08's even have that feature? All I know is I'm getting less fuel economy these last few weeks since the weather has gotten cooler.

 

I don't think the 08's had that.
If you do, it would be displayed in the odometer window (pushing the selection button on the side) and scrolling through.

Mileage, trip A, trip B, range (miles remaining), clock