I have an '03 Retro 1800. 8000 miles *** YES. 8,000. Just bought it last January. It has Hypercharger, PowerCommanderIII, opened up stock exhaust. I GET INSANELY LOUSY GAS MILEAGE / 20 MPG. I checked / re-set PowerCommander program - to no avail. ANY THOUGHTS ???
YES!! STOP RIDING IMMEDIATELY! Check your oil level I will bet you are overfilled and it reeks of fuel. The 2002-2003 models have a Fuel Pressure Regulator, or FPR , and these are a know fail item and when they fail, they allow too much fuel into the combustion chambers and the excess fuel washes down teh cylinder walls into the engine case thinning the oil and more than 1 engine has been destroyed by this. Change the FPR here are the instructions; https://tech.bareasschoppers.com/car...ure-regulator/
Once that is done, change the oil and ride around the block. Then change the oil again to be sure you got all the gasoline out of the engine case