It might be just a quirk in the TuneEdit software. Before putting in a DJ O2 sensor bypass: 1) E-mail Wayne and ask him if his program is really turning off the sensor when you download the program; 2) Assuming that your new L tables have reduced the backfiring, you should notice increasing backfiring over time as the ECU adapts if TuneEdit is not turning off the O2 sensor.

Actually, it's not really turning off the sensor. It's fooling the the ECU into thinking that conditions for closed loop (low throttle position) are never met, so it never uses data from the sensor - i.e., it always uses the data in the L tables for low TP. This is how the DynoJet O2 bypass works.

Hi dougl...I emailed Wayne and he asked me to re-install the latest TuneEdit software which I did. This fixed the problem of not turning off the O2 sensor.

So I used one of the tunes you sent links to and downloaded that to my bike with the O2 sensor un-checked.
This seemed to work fine although I still have the message at the bottom of the screen saying 'Open Loop, Conditions not yet met!!'

Anyway I went for a long ride on sunday (550k) and everything remained constant - although just for piece of mind I'd still prefer to have the O2 eliminator connector plugged in.

Oh well, can't have everything.

Thanks to everyone that has responded to date. I'm slowly getting the bike sorted

Another question for Wayne. Probably just a software glitch. There's no Way it can be using the O2 sensor data all the time and have the bike run well.

I used the PCIII O2 bypass to deal with the backfiring issue and I don't even have the version with the O2 sensor check box.

I believe I asked Wayne about this and that he said to disconnect the O2 sensor under the side panel. If you're talking about plugging in the PCIII O2 eliminator, then you should probably leave the O2 sensor box checked so the ECU will be looking for the signal from the PCIII O2 bypass.

If this has helped eliminate backfiring, that's all you can expect.