I'm lost and I've looked all over the forums and found a dude with the same issue but his thread just stopped and no one is replying on it.

I took my Forty Eight in for it's 5000 mile service and when I got it back I noticed I'm only getting about 23-24 mpg. No using the light I'm getting 39mi to about 1.8 gallons of gas. I was getting about 38 to 40 in the city.

There is no fuel leak. I'm going to replace the spark plugs but can bad ones hurt fuel this much? Tire pressure good and I put 93 octane in it. I've made sure the breaks aren't riding.

I have:
Vance Hines two to one (no O2 sensors).
Power commander V (nothing crazy tune)
Stage 1 Air

I have noticed every now and then it sounds like it trying to suck air like a (phhh tummmmm) sound one time it even died but started back up. It has been a slow start lately but I just figured because of the colder weather.

Any help or just things to look for. I'm completely lost. I don't know why it would be fine and just all of the sudden bad with no noticeable ride difference.

 

It's got to be something with your tune. Where did you buy your PCV? Have you tried reloading your tune that was working before the service. Did you ever have a dyno.

 

Yeah I reflashed it when I first noticed the poor fuel economy. Never had a dyno. Bought it at the Davison dealership

 

If its under warranty I'd take it back to the dealership and tell them to fix it. I get around 41-47 depending where and how I'm riding.

 

it's not it's a 2011

 

If you don't have the auto tune you have to get a dyno. You can use a stock base tune but you need to customize it. Especially if you have no O2 sensor. I've got the x14ieds and I get about 40 around town and 50 on the highway. Runs fantastic. Take it to a pro or get the auto tune.

 

I don't believe it's the tuner but I don't know what it would be. Since nothing changed but the 5000 mile service and since he already installed the same tune that worked fine before service. Seems like something was done during service but I don't have the experience to know what it would be. But based on logic I don't see it being the tune. Since you said that the breather doesn't sound right, I would pull it and check the filter. Also check the intake opening to make sure it's clear and moving freely. If that all checks out I would make sure all of your connections to the pcv are secure and connected properly. Just to make sure they didn't disconnect and/or reconnect something wrong. Only other thing I can think of is to verify that you don't have an exhaust leak. Outside of that I don't know.

 

Is the inside of your muffler black with soot/carbon buildup?

 

Somethings wrong, what do the sparkplugs look like? That's less mileage than a Ford F150.

My '91 883 gets 50mpg around town no matter how I drive.

John

 

Take the PCV off for a tankful and see what you get. (I think you should be able just to disconnect the power for the PCV rather than disconnect everything.)

It will run lean but shouldn't hurt for just one tank of fuel. Check you mileage for that tankful, then you'll know if it's your tune, or something else.

Easy and simple.