Are you SURE the 07 has an 02 sensor?
I was not aware of this. I have an 05 S2R 800. Great bike, ultra reliable. I bought it May 2007 with 1250 miles. Currently have 13650 miles on it. Runs like a champ so far. I had an M800 before that. 800 motor is in my opinion that best 2V motor they've ever made.. Better than the M1000DS
If i remember correctly, i remember reading on the old DML that the 07 and up were under the #3 standard or something like that. I dont remember what comes before the number but the 05-06 s2r800 were under the #2 emissions standard while the 06-current s2r1000 were all under the #3 standard. That was the reason for the o2-sensor.
I have also read that not all 2007 s2r800 have an o2 sensor. Something about the euro version having to have while some dont.
I cant verify but that is what i have read on the boards.