Hyper exhaust question

[cencalal]

I need to ask this question here because once again I'm getting no replies on the Hyper forum at Ducati.ms.   Always get good advice here for my M695.

I'm installing Zard 2 into 1 headers on my Hypermotard 796 and since I'm running the 1100 Sachs shock, I'm going to need to relocate the O2 sensor bung on the vertical/rear cylinder pipe, to clear the shock reservoir. Like the oem pipes, there are two threaded bungs in each headpipe - a big one (16mm?) for the O2 sensor, and a small one (10mm?) two inches away that's plugged. What are the small ports used for? I'm guessing for analyzing exhaust gasses... I'm thinking of cutting out the small one on on the vertical cylinder pipe and relocating the O2 sensor in that location - any reason not too? 
Thanks

[koko64]

I guess dyno tuning and mapping each cylinder . A lot of people don't and just use the ega sniffer in the exhaust outlet. Maybe swap bung locations? Or reflash the ECU and delete the O2 sensors? Smartmoto have eliminators that work and allow a PCV to map the whole range.

[MonsterHPD]

Older pipes, like on my Monsters 2002 and 2003, only have the small bung (used to be 1/8" pipe thread, I think they may have gone metric now ...) for the CO2 analyzer.

I will (eventually) use that for a temp sensor element during dyno testing (to detect knocking), but otherwise I have never used them on any bike since 2002 ....  so I would do as you propose if I were to retain the lambda sensor.

However, I do not know if a Ducati shop use the small bungs for anything, since they still put them on the pipes.   

If possible, the lambda sensor should not be positioned directly in the outer radius of a bend. Any liquid moisture in the system will blast the lambda sensor when you start the motor and that can lead to cracking of the ceramic sensor element (which is pre-heated).    

Often, though, you just put it where it will fit without hitting anything ....  

[Duck-Stew]

IIRC, the above post mentions pipe thread.  It’s not American pipe thread, but BSP, British Standard Pipe thread.

I have nothing to add to the OP’s post.

[cencalal]

I wonder if this would work - it would fit and be the cheap and easy way to get this done.  There are both 90º and 45º oxygen sensor adapters, either of which would allow me clearance to the shock reservoir.  Problem is they pull the tip of the sensor back out of the exhaust stream, causing a lean reading, according to some automotive websites.  But what if I put one at the front/horizontal sensor as well, to equalize the front and rear readings?  Is the ECU only comparing the two readings and trying to balance them, or is it looking for an actual number/value?  There don't seem to be any angled O2 sensors out there, only the sparkplug shaped ones...