So i went through the DTC the other week and found 3 error codes and reset them.  After reset only one DTC keeps comng back and i know the cause of that so its not a concern as i will fix this issue be reinstalling the clutch switch.  (DTC B1154 CLUTCH SWITCH INPUT SHORTED TO GROUND)

The 2 codes that have not reappeared are P0152 REAR OXYGEN SENSOR HIGH / ENGINE RICH and P0132 FRONT OXYGEN SENSOR HIGH / ENGINE RICH. 

I presumed that the 2 DTC were caused after the previous owner added the V&H 2 into 1 and hypercharger prior to him installing the Arlen Ness Big Shot (ANBS)  and setting it up.  After the ANBS was setup i presume the bike would no longer be running rich but who ever installed it did not reset the DTC errors.

Due to the fact that i have reset the DTC and the 2 codes have not reappeared i can only assume that the bike is no longer running rich, is this a correct assumption?

Now today I had to go to the HD dealer today to get a new fob coded so they down loaded the info from the bike which showed the current DTC B1154 as well as the historic DTC of B1154, P0152 and P0132.  The mechanic then tells me that the bike is running rich as the DTC has indicated that.  I dont think this is correct as its a historic fault code and not a current fault code, am i correct?  The ENGINE RICH faults have never returned after i reset them a couple of weeks ago when i got the bike.  Mechanic has also stated that he'd removethe Arlen Ness Big Shot and replace it with a Screamin Eagle Race Tuner, whats the thoughts onthis idea?  At present i'm getting about 6 litres to 100km, would thecSERT improve this?

Any answers?

What bike etc
Yep as far as the codes go. I got the same codes when I put on my K&N, cleared the codes had the bike tuned and they never come back. I would also expect that the bike would have been tuned due to the alterations as it should be running lean with no tune. The previous owner has tuned the bike to run richer than stock which is a good thing. The Sert may give you a bit better improvement but at the end of the day he is trying to sell HD stuff and that is all he knows. 6L/100Km seems not to bad about 300ks from a tank is about right.

 Sorry, shouldve stated its n 07 FXDWG 96 cube.

Galbo If your worried, find a local Dyno shop and get them to do a run with AFR's.
Shouldn't cost more than $100 , and you'll also see what sort of power she's making, and if you need further tuning.

 Not worried as it runs fine and doesn't seem to bad on fuel consumption. Just want to know if its a historic code and not a current code does this mean theres no issue.

It's an historic code. Do you have the manual as it will explain the difference. between both. Mate I wouldn't worry about it. I check mine occasionally, I have had the 152 come up once or twice in the past. Also a good thing to keep an eye on is both you exhaust flange bolts that they are tightened correctly, and you intake manifold is not leaking. Those coming loose can cause those codes to be thrown as well.