Hi,

2009 Sporty with Screaming Eagle slip ons and a free flowing air intake (RamFlow); that's about the only tweaks.

The bike has the O2 Sensors per the factory, so other than running slightly lean why would I need to do a dealership stage 1 flash etc if the bike is running fine (have run Harley's for 20 years so not new to them).

Am new to my Sporty and EFI though so a genuine question.

 

Because it's not running slightly lean from the factory and now that you did an air cleaner and a free flowing exhaust I bet it's running pretty damn lean. Is your bike going to die tomorrow? prob not. Will it be bad overall? yes

C/N yes you need something to make it run a little richer

 

So my O2 sensors are just window dressing? I mean everyone seems to overlook the fact that the bike has a closed loop AFR system on board....and my basic understanding of this tips that it should be managing my fuelling etc.

 

Great question. I did download on 2012 1200 but often wondered what I bought. Been told by some that it didn't change AFR. Mainly increased revs. Evidently there's some sort of rev limiter with stock mapping. It does rev out higher and more range through gears. Seems to have better power band. But biggest gain in performance was due to SE Slip Ons.

 

Found this in old thread about Rev Limiter
All that happens is the EFI cuts fuel and the engine speed slows. You feel the engine start to loose power just before it happens, and that's your cue to clutch it and shift up.

 

So I was just reading this from the Nightrider site that helps cut through some of the myth that seems to be floating around.
http://www.nightrider.com/parts/ied_faq.htm
Interesting read....

 

Great reading. Interesting that complaints about popping, etc is due to exhaust not intake. Nothing to do with leanness

 

That is very interesting, but why is it that every single person on this site says it runs too lean. or it runs lean from the factory. Why is it that a xied at a minimum is recommended? Playing devils advocate

 

Factory target AFR in closed loop is 14.6:1. The o2 sensors work to keep that AFR at that 14.6:1, regardless of temps, humidity, elevation, worn parts, dirty air filter, etc. That is what they are designed for, and they do a pretty good job at it. And even if they do their job and keep the AFR at 14.6 or 14.7, that is the best AFR for a complete burn and the least air pollution, but it is not the best AFR for performance.

But when a free flowing air filter and free flowing exhaust is added, it changes the AFR so much, that the o2 sensors can't get a read to even send a coherent signal back to the ECM to make the adjustments needed. The stock narrowband o2 sensors just can't handle that much change.