last month i picked up a 2006 ultra classic w/ 23k on the clock. it's all stock with a couple minor upgraded items like a bigger windshield and a few chrome trim bits. riding around town gas consumption seems pretty normal however on the freeway it gets horrible.

last weekend i took a 2 hour each way trip averaging around 75mph (cruise, almost all flat) and i could almost watch the gas needle drop as i was riding. i could not go the entire 2 hours without having to refuel, and by my calculations i am getting about 23mpg on the freeway. from what i have read this is almost half of what it should be. checked the plugs and they looked good, no gas leaks, no fluid leaks of any kind at all really. i am guessing that the previous owner modified the bike and then just swapped out the stock parts before selling. unfortunately while i bought it from the owner's family he had passed so no one has exact first hand knowledge.

anyone have any thoughts as to where i might start? i've never owned a bike new enough to have fuel injection, they have all been carbs.

 

Check to see if it has a piggyback tuner such as a PC-III under the seat. I doubt if someone would have dynoed it that rich. Does it smell of gas when you stop?

 

my first thought was a leak but i didn't see a drop of fuel anywhere nor did i smell anything. i'll pop the seat off when i get home tonight. thanks.

 

might be under the right side cover as well.

 

Do you have a lift to get the wheels off the ground and check for brakes dragging? Caliper pistons can get dirty and stick in the bores and not fully release the brakes when the lever/pedal is released.

By "looking good", do you mean the spark plugs were white or tan rather than black? What color is the muffler exit area? Do you have any O2 sensor codes?

 

i have a lift, but can't really get to it yet. still unpacking the new place and had to cram my tools and lift from a 2 space down to a 1, and won't get to unpacking for 12 days or so.

yes the plugs are tan. the exhaust area has some carbon but nothing i would consider excessive. no clue on the codes. i'll have to explore the forum a little more to see about getting them.

 

Bigger windshield & 75 MPH? I'd guestimate that combo will get you 23 to 25 mpg max. Takes a lot of throttle for that 88 motor to push that wind. Slow down & fuel economy will go up substantially.

While you have it in the air checking for brake drag, check wheel bearings too.

 

My TC88 with stock height windshield would cruise all day at 75-80mph across the midwest and still get 38-40mpg.

 

I agree - my '09 w stage one (96) gets in high 30's to low 40's when riding 75 for an extended period. Movie it to 60-65 and its low to mid 40's - and that's on crappy West coast gas!

 

I know when I have the cruise set on 80mph my mileage is 30-32, drop back to 65 and get upper 30's, 55-60= low 40's, I think the wind resistance just kills the mileage at those upper speeds but your 23mph is pretty bad. As someone mentioned check for a tuner if not you may want to get it tuned.