I have an 01 EGC TC88 that I get 28-32 mpg since new, has 38,000 miles on it now. On Sunday the 12th left San Diego for Tucson then headed north to Grand Junction. Usually at 130 miles I better be near a gas station cause I'm on fumes. Well milage started creeping on up and by the time i reached Grand Junction was in the 170 mile range and using about 4.2 gallons to fill up. Left Grand Junction the 19th and 20 hours of straight riding later pulled in my driveway. Had a couple fillups up north that got 180 miles or so on range but closer I got to San Diego milage dropped, but still in the 150 range. Have a Fuel Moto Power Commader installed on bike and was wondering if the map they used is for higher elevations or something along those lines, bike is fuel injected and have the stage 1 air filter and rinehart true duels, everything else on motor is stock. This was first long ride on bike as I use it as my work vehicle, 22 miles each way, 4 days a week. Will buy a new seat before next trip, bought a gel pad at GJ Harley did not help. Had 14 inch Yaffee Monkey Bars installed before trip and they were worth every penny, had back surgery last November and no problem at all, although azz hurt so bad might not have noticed anything else. After long rambling details should I check on new fuel maps or just leave it alone. Opinions appreciated

 

any bike tuned well and not dragging a ship's anchor should see at least 40 MPG running at 65 MPH...anything less really points at an incorrect tune.

I think you are onto something....maybe the air density is not being measured properly at sea level- which is your baseline.

as you rise in elevation air gets thinner and fuel mixtures need to be adjusted. on a carb'd bike with a conventional carb ( S&S, Mikuni etc. NOT the Keihin CV carb which was on H-D 1990~2006) a smaller "leaner" jet would be put in place so that the mixture stays correct, overly rich mixtures do not make better power than a correct mixture, but worse.

you could have a chat with FM and see what they say, they know the PC better than most



Mike

 

An 88 getting less than 35mpg. There is something wrong there.
I've got a cammed 106 and I'm getting 50mpg on the highway.
Get it dynotuned. They will measure the a/f ratios coming out of the tail pipe and write you a custom fuel map. Your mileage will increase and likely get a few more ponies out of it

 

Did you possibly fill up at a couple of gas stations that had straight gas (no Ethanol) vs. some that had it? I know it makes a difference in mpg's, I just don't know how much of a difference.

 

Higher elevations = less air= less fuel= less power= better mileage. I agree with Gearhead, straight gas has about 10% better mileage that the ethanol crap!