With a new set of plugs, ride it up the road/freeway for a bit, long enough for it to get hot, pull over and remove and check your plugs. If they are white hot with no coloration - Too too lean for sure. Too much air, not enough fuel.
Nice tan color - bike is running somewhat correctly and I wouldn't worry too much unless you wanted to get a real nice tune done to perfection. Decent air/fuel mixture.
Black and sooty - Too rich - Too much fuel, not enough air.

 

Having just went through the cam/intake/exhaust upgrade on a 12 FLHTCU 103". I went with the fp3. The main thing with me was customer service. I've been buying V&H products for 30 years, and any time there was an issue they stepped up. If you go with Dynojet, they will bill you for the dyno, then you will pay for the license for the flash once done. You can buy a Power vision tuner, but now you're at $500 plus the dyno. The power vision unit is large and will need to be mounted on your bars, whereas the fp3 will easily tuck under your left side cover. My local HD dealer is all about Power Vision, so if you go there you'll get guys that use the software daily.
V&H built me a custom map. I just had to e-mail them the cam specs, and a few days later the map was ready. I simply flashed it to the bike and done. Couldn't be happier with the map. No decel popping, not too rich/lean. I really don't believe a dyno would yield major changes to what I currently have.
If you buy the fp3, get it from Amazon. If you don't like it after a couple of weeks, send it back. They'll take it back...........

 

Not Dissing the FP3 but there is lots of misinformation here.

The power vision can be had from FM for $399 not $500. They will provide you with an initial map/maps based on your setup that will be very close and you can auto tune them. They will also provide lifetime maps and support should you have questions or change your setup. You will be dealing with the guys that run the dyno on a wide variety of configurations daily. Just like the FP3 you don't have to pay to run it on the dyno.

Not true. I run mine in my pocket or saddle bag. If you want to interact with it real time you will have to have the unit in sight (velcro or zip ties if you don't want to use the mount) same as a phone with the FP3. With the Power Vision software on your PC you can download an auto tune session and compare the proposed changes with your current map in the form of a 3D graph before deciding to flash them to the bike or not.


You can ask them why they prefer the PV but you might get the same response that I did when I asked... It interfaces seamlessly with the dyno, and ECM, the adjustments over the ECM are equal to the old race tuner and that the new Harley tuner will not tune outside of EPA regs. If you get a different reply by all means post it.

I have yet to find a shop that will perform a build locally with the FP3. I am sure they are out there but if you want to go into the motor later your best bet for nationwide support is going to slant one way.

 

My opinion is when the bike was stock it was on the lean side not knowing what was flashed or not you would benefit from a tuner do your homework between the pv or the FP3 . I use the FP3 v&h has proven to me to be a stand up company. Check out the FP3 real close and it will do what the claim. If you download the free app you can check it out in demo mode