How does it work?

[BASS-TREBLE]

Just curious.
While cleaning the air filter on a BMW R1100GS I saw what must have been the oxygen sensor in the airbox which made sense, oxygen sensor > throttle position sensor > fuel injector and then the exhaust sensor.
Then you see the guys that put an airfilter straight behind the throttle body of each cylinder which bypasses the airbox, so where does the oxygen sensor go?
My only thought would be that they would put the existing sensor on one throttle body but that wouldn't indicate the amount of oxygen going into both cylinders added together....
Any kind people out there with a good explanation?

Picture shows a setup.

Cheers guys, and girls

[Motu]

That won't be an oxy sensor in the air box,most likely intake air temp.O2 sensor is in the exhaust before the cat.

[imdying]

Yep, IAT or IAP in the airbox, o2 sensor in the exhaust.

[cowpoos]

That won't be an oxy sensor in the air box,most likely intake air temp.O2 sensor is in the exhaust before the cat.
could it also be a vacuum sensor?? as with the right calculation..it would be able to factor air temp and air volume going into the engine???

[Ixion]

Air flow meter ?

[Motu]

A MAP (manifold air pressure) sensor used as an air flow meter goes after the throttle body and not used on bikes,MAF (mass air flow) sensor goes before the throttle body,but will pass all air through it,so will be fairly bulky.Sounds like it's just a small sensor same size as an oxy sensor,so air temp or baro both of which will give some base for air density.

[Ixion]

Only thing relevant in the parts fiche for the air cleaner and housing is the air temperature sensor.