FMF Q4 pipe O2 sensor.

Hi Guys

Over here in Blighty I have just purchased a shiney new FMF Q4 pipe.

My question is, can I just diconnect the O2 sensor that's in the stock pipe or should I have a boss welded into the Q4 and mount the O2 sensor?

What would happen if I left it off?

Regards

Steven

steven9586 wrote:

Hi Guys

Over here in Blighty I have just purchased a shiney new FMF Q4 pipe.

My question is, can I just diconnect the O2 sensor that's in the stock pipe or should I have a boss welded into the Q4 and mount the O2 sensor?

What would happen if I left it off?

Regards

Steven

I ride my bike without the O2 sensor and it is no problem. (sweden also have that O2 system installed)
But I also have adjusted the CO value to about 10 and i have the FMF fuel programmer installed.

The O2 sensor is only used for idle and some low rpms then it gets into a closed circuit and is kind of disconnected. (it is made for a "green enviroment" purpose...)
So ive been told anaway...

Its all up to you but it works for me. (so far..)

Hi Steven, The reason why the engine needs the oxygen sensor is because the amount of oxygen that the engine can pull in depends on all sorts of things, such as the altitude, the temperature of the air, the temperature of the engine, the barometric pressure, the load on the engine, etc.

When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing (This is when you would benifit from installing a FI programer and the having it set up on a dyno)

So if you are just replacing the silencer you will allso be doing away with the EX-UP valve, This valve helps with bottom end torque, something you need on a 250 thumper, so i would allso fit a power bomb front matching pipe To get some of the tourqe back,

If you are only replacing the silencer because you want it to sound a bit more fruity i would defo fit the front pipe and allso get the spigot welded on so you can fit the O2 sensor,

Regarding the EX-UP valve, it would be easy for you to just remove the cables from the servo, but leave the servo conected to the wireing as not to flag up the engine light,

Hope this helps you and good luck with what ever you do,
V-Tec