I get about the same mpg as most, 07 FLHTC low of 42 high of 48 on interstate 75 mph, had a used 05 FLTHC that had mod's, it got 32high highway, the used dealer said that was what to expect that nobody got 45 mpg, soI left it at a Harley dealer and asked them to make it stock, I didn't notice any difference in power and the high went to 46 highway 40 2 laner's.

 

I have the usual mods including a PCIII, Rush 1.75 slip-ons, and K&N AC. Any discussion about mileage would have to include those who have installed EFI controllers, which most have done. Here's my experience over the past year:

City: 38-40mpg (frequent cold starts, lots of stop-and-go).
Highway, 55mph: 50 mpg
Highway, 65mph: 47 mpg
Highway, 70 mph with 25-knot headwind: 40 mpg

I've done quite a bit of tweaking to my PCIII to attain this mileage, mostly by leaning the cruise range, and I think this about as high as I'll get with this SG without going too lean with the A/F. I'm trying to find that ideal compromise between mileage and heat, and feel like I'm very close at this point.

 

I have a stock 07 Ultra and I average about 45-48, But just let me say it's not about the fuel mileage, It's all about the RIDE and the ride dosn't get better than H.D.

 

16k miles on my 07 RKC and I average about 48 mpg... Better when I behave on the throttle and use 6th on the highway... I live in a pretty rural area and most of my riding is either long 2 lane roads or highways... My 32 mile one way to work only has 4 lights or so spread out on it and Speed Limit is 50...

I tested the speedometer and it is only about 2 mph off at 70... The odometer though is spot on...