Put on a PCV and gas milage fell from about 37-38mpg to 31-32. this seems extreme for the mild power boost. Is this typical??? I'm not being heavy handed either I got this mpg on a slow group ride.

 

That seems way off. The tune must be off.

 

My tune is dead on and I too dropped numbers close to those. I have tons of other performance mods too..cams, intake, throttle body etc.....I know this the more power and tq u make the less mileage u get.

Have the tune checked to be sure it's all where its supposed to be and then if the numbers don't improve carry on knowing there's going to be a trade off with increased performance in the rom of decreased mpg. That's a reality in the MC world just like the car world. Harley's rarely maintain the good stock gas mileage after we start making them run the way our money should have gotten them to begin with.

 

Did u just install and go or did u dial it in using an auto tuner....or Did the dealer do it?

 

That don't sound right. My 07 fxd with screamin eagle stage 1 intake with k&n filter, vance and hines straight shot slip ons, vance and hines fuelpak and nightrider xieds gets around 38-40mpg.

 

hook it up to a computer and check the throttle position. Unless you filled up on low test gas.

 

I have basically the same thing and get the same mileage (38-39mpg) but the Xied's are not true tuners. I suspect the PCV and others use more fuel throughout the power band. Makes me glad I have the Xieds.

 

Run a few tanks though it too, you can't tell just off one tank.

 

I have a stage two and get 41.

 

^Well that really solves the OP's issue.