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Ok, I have the S2R 1000 and it has the surging issue most of us know about. I unplugged it a couple of months ago and it runs much better. I was out of state yesterday and visited another dealer to see what their shop was like. Good group of guys but as I was talking to them I brought up their wrench that I had surging and I had unplugged the O2 sensor and was thinking about putting on PC III. The thing he said that alarmed me was that I should plug that 02 sensor back in because without it the bike would run dangerously lean and could damage the bike. This runs contrary to what I had thought was happening. I thought an O2 sensor in a closed loop made the bike run extremely lean in the lower RPMS to help it pass European emmission standards. By taking it off, I felt that if anything I was richening up the mixture. The tech went on to say that the lean condition would occur above 6k rpm. Again contrary to my limited knowledge of EFI Systems that say the O2 sensor has little or no bearing on how the bike runs above about 3 k.

So, which is it? Can someone set me straight and let me know if I should listen to this guy?
 

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That is all going to depend on how the default map looks. Maybe Brad will chime in on this one. I only have experience with cars and in their case the ECU looks at the signal as a steady signal programed by the engineers as a default, in case of failure.
 

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I believe that your original understanding is more correct than the version the other tech was telling you. The easiest thing to do is to pull the spark plugs and get a general reading. If there is anyone near you with a CO / HC sniffer you could plug it into the exhaust and get a reading too. 2% to 4% CO should be fine. Anything lower is getting lean.
 

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Does anyone know about installing a Termi system which includes a new ECU and open airbox on a 695? I was told to remove the O2 sensor, essentially unplug it, and leave it at that. I'm skeptical because the new F.I. system is closed loop but I don't have any idea if the replacement ECU is an open loop map or if it is still looking for the O2 signal for proper fueling.
 

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I had to disconnect the O2 sensor when I installed the Termi DP ECU on the S2R1000. Runs like a bat-out-a-hell. Since then I got rid of the Termis. They suck. I bought the Desmoworld/Sparks exhaust....but I kept the ECU.
 

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Spinned said:
I had to disconnect the O2 sensor when I installed the Termi DP ECU on the S2R1000. Runs like a bat-out-a-hell. Since then I got rid of the Termis. They suck. I bought the Desmoworld/Sparks exhaust....but I kept the ECU.
So you have now desmoworld "full system" and dp ecu?Or stock ecu.. ::)
 
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