I have a friend that has a 05 Heritage, carb, 1988 sportster needle, K&N air filter, V&H staggered. I have the same set up on a 02 Heritage. For the last 2 years we have both been getting around 44 mpg. All of a sudden his gas mileage dropped to 36 mpg. His plugs look good, cleaned air filter, changed oil an it runs great. Any ideas?

John

 

it's probably because the price of gas has gone up! just a thought, lol

 

Air preasure in the tires, weight gain, brand of gas

 

Weight gain on me but not him. I did have Mexican food last night and he didn't. Will that kind of gas make me lighter?
His gas mileage has been around 36 mpg for about the last 5000 miles and it dropped all of a sudden.

 

Ask the place where you got the gas if they have changed over to the Federally mandated summer oxygenated blend. You will often see a drop in mileage when they start using that stuff.

 

My Sportster barely gets over 44 MPGif I EVER got that onmy carb'd Heritage I'd thank the lord as previously stated you are probaly just looking harder at the gas gauge these days I think mine gets about 34 if I am gentle with it

 

check to see if he has a petrol leak... with said mods, there's a possibility something ight be loose or worn. i had similar problems on another newish bike. lucky i had it checked as the mechanic told me another bike caught fire in a tunnel...

 

What % ethyl alcohol (corn) was the gas. I know that the more ethyl you add the moreyour mpg goes down. Around here we are at 10% but I heard that they want to up that to 15-20%.

 

I second the ethanol content. Missouri switched to 10% statewide a few months ago, and I know people are complaining about a 1-2 mpg loss in cars/trucks. I personally haven't been able to tell much difference between KS, MO, and AR gas in mileage, but I think the 07-08 closed loop system may offset that change a bit. Gas is junk these days. I noticed a ping in mine for the first time while passing a guy this past weekend. I figure that's what I get for fueling up in a small town.

 

Ihaven't heard anything about adding 15 to 20 %more Ethanol, Harley has tested the 10% Ethanol and their ownermanuals say it is okay to use and won't damage the engine. If at all possible I won't even use the damn stuff unless I have to, but I sure wouldn't use a 15 to 20% mix.