I have a stock 2008 Heritage Classic. Somewhere I read that if you upgrade only the breather unit, that the stock ECM could handle that and adjust for it. Can't remember where I read that, though..??

 

Wrong !!!! you do the A/C you need to do a fuel management system. Pipes only is the only time you can get away with leaving it original

 

+1

 

You increase the air flow. It thins out the air mix. Causes the motor to run lean.

Before I get pounded. The o2 sensors are narrow band. If it's far enough off the ecm will go into open loop.

EFI Harley's come equipped with 2 “switching” sensors…also known as stoichiometric sensors. Unlike wide-band sensors which can measure and control over a wide AFR range (10-20), switching sensors can only control within a narrow range (+/- 0.5 AFR). They are designed to correct for atmospheric changes only.

The sensors tell the ecm to look at the Closed-Loop Bias Table. Everything the ecm does is by a look up table. If the ecm sees a request for AFR that exceeds 14.6 it goes into open loop. Thats another table. There are 11 of them.


If it starts burbling or popping that's a hint.

 

I would put a PCV even if it was the only mod done

 

I did a K&N foward facing small cone on my 2007 Night Train and had no real issues that I noticed. I was woundering if once I put it on I might need to trailer it to the shop for a dyno. I heard the 2007+ could self adjust somewhat and that the 2010+ were even better at it.

I started up the bike and it sounded fine. I wanted to see if it tossed a check light. Then I did a ride around the block, then a ride with the wife. No major issues other than the intake sounded louder as did the exhaust.

I have heard bikes with tunes make some noise/poping on decel, and they said it was o.k. and did no damage. Asked if the tune was messed up and they said it was where they wanted it...

Who knows.