Many of us find we get comparable even slightly better mileage than bone stock. You are right to regard a new air filter, exhaust and tuner as a stage 1 package. Personally I would also include a change of cams, to complete the conversion, but also include a dyno tune to optimise everything.

Our bikes come with many compromises in their set-up, so they can meet EPA noise and exhaust emissions regulations. These include a very quiet induction muffler, as well as the quiet exhaust mufflers, but the cams are also designed for reduced noise. By replacing the lot you are undoing all the EPA harm and should enjoy a significant improvement in performance!

 

Mine is not very good at all. Stock TC88 w/ Big Sucker a/c, and stock head pipe with Rinehart slip ons and a Fuel Moto tuner. 33 mpg.

 

I have a 2012 limited and did this about a year ago. Stock mpg was around 42 and now getting around 38. I ride mainly long distance running around 80-85 mph on interstates. Hitting the mountains, I slow considerably to enjoy the ride and mpg goes back up to 42 and sometimes better.

For reference I have power vision, super trap 2-1 and AN big sucker.

 

By way of comparison, my Stage 1 2010 FLHTK was averaging around 47-48mpg. That was with a Ventilator, Jackpot pipe and 4" mufflers, and a TTS.

 

I get 40-42mpg with stage 1 on my 2012 RK. About the same or a little better mpg than stock.

 

I finally got my Nightrider FL-XiED-10 adjusted for my set up... Took a 500+ mile trip last weekend down to KY and back... All State Route & I-75 going 65-75 MPH,,,, consistently got 49 MPG riding 2 up and loaded down.

 

I just put SE cams and PCV w/auto tune on my Heritage. My hiway mileage went from 44-47 with HD stg 1 flash and suppertrapp mean ******* long drag pipes and stg 1 intake to 32-36 which to me sucks bad.

I hate it so am pulling cams and tuner off and selling them. And it so frigging loud now we need to wear ear plugs even with helmets on. Just did a 1000mi trip to Dallas last wknd and am ready to have my old bike back.