That's interesting, I hadn't read that before thanks for pointing it out.

PO131 and PO151 are set when ECM detects an excessively lean condition for a specific length of time.

I would venture a guess that the excessively lean conditions are known to cause damage in the near term and running a engine with lean conditions caused by increasing air flow and not changing the map could cause problems in the future, how near or far is unknown. It would be interesting to hear what Dynojet,Fuel Moto and HD have to say as they all recommend a tuner with Air Cleaner and exhaust changes.

I've never read or heard someone say you don't need to change the map until you see these codes.

 

Since I work in the automotive field and I know these bikes have to meet the same(mostly) OBDII standards as cars. And, since I don't have anything to sell...

Most vehicles have a correction window that is fairly large. 20-25%, sometimes more. Depending on EPA mandates at the time and what the manufacturer thinks the vehicle might be subjected to. They must compensate For temperature, altitude(baro pressure), engine wear, sensor and cat degradation, etc.

Where the problem would be is if your near the limit and go into a high altitude area or colder area. Then the check engine light would pop on because it strayed from the possible correction limit. Also at WOT the O2's are disregarded and it goes to max rich fuel trim. This is where a dyno comes in handy...not just a tuner. Unless it shows you corrections it making like Auto Tune or similar can do.

 

Thanks for all the additional info guys, I appreciate it. The more I know about the bike the better