between 30 and 55 depending on elevation and how fast I am going, I usually get 40 in Fla at normal cruising speed of 85 , drops a lot after 90 though. Got 55 up in BC this year running pretty hard through teh mountains too, on 87 octane no less.

 

Higway to combined... 30-38 MPG. However, I do have a propensity to roll on it.

 

According to the good old "take trip milage and divide it by how much gas you just put in" method, my week-old SG is getting right at 39/40 mpg with the Stage 1 103" and Heavy Breather intake.

 

My build has about 2500 miles on it but only was retuned several days ago. I got 34 on my first tank. is it possible that mileage will change as the motor breaks in?

 

My '06 Road Glide with 94/98 was avg. 45.

 

42 mpg highway

 

You're getting a good spread of replies here. Frankly what does it matter? Compared with the cost of a major engine upgrade your mpg shouldn't influence you.

Theoretically if you ride a big-inch motor exactly the same way as a stock one the mpg will be the same. But the reason for upgrading is to improve performance, which results in increased fuel consumption!

In general you will get an increase in consumption, but most of us who have done it are very happy.

 

I got a 45% increase in HP, a 25% increase in TQ and I lost 10% in gas milage.
Of course I get on it more now than I did when it was stock too. So I just fill it up and go.

 

I'm more curious about the touring range. Sure we all can rip on 'er, but when you're goin easy and makin miles. I ride different when I'm going for a day trip vs. a week trip.

The countdown is usually 400 km for me. But I guess I better check it sometime with an odometer...

Usually after 3 hours you should stop and take a break anyhow...

 

92hp/98tq and 38-42 mpg