When I first got my 99 Ultra I got 50mpg 2 up. Now I am getting 37mpg 2 up. What all can I do to get it back up there? As far as I know the only real thing that can be changed is the TPS. I used a gas analyser & set it by the TPS & went from 1000-600 HC down to 200 at idle & 150 @2500rpm's. I tried setting up the TPS by the manual but that had the HC way up there. All the sensors were replaced new about a year ago. I have adjusted the valves a couple of times also. Moving the TPS just seems to be a lot from where the manual says to start. I don't want to run it lean is why I stopped @ the 200-150HC's. Anyone with any idea's

 

Whaaa?? TPS?? 1000-600HC down to 200 at idle and150@2500rpms??? I am sorry, but, I don't understand what you are asking!

 

TPS is throttle position sensor HC is hydro carbons. If you don't have enough fuel ot will run lean which can burn pistons, run hot. Optimum fuel ratio is 14.6, but since it is air cooled, I am not sure if it should have more fuel to help keep the engine cooler. That is why I adjusted the tps for the 200-150 (200 being at idle & 150 at cruise rpm)

Toby

 

Just shooting from the hip but could be fuel related? Try picking up a bottle of Star Tron, an ethanol neutralizer. It is a shame we are forced to deal with ethanol. I just had a lawnmower serviced because of it. I also run some Techron fuel system cleaner through my bike from time to time.

 

I'd put money on fuel quality.