Adjusting the CO will only alter the fuelling slightly and only at tick over and very small throttle openings (up to a TPS reading on 18 I think?) The CO setting has no effect on the fuelling in the rest of the rev range at all.

Don't drill holes in your air box and/or fit DNA filters and expect the CO adjustment to compensate for the extra airflow.

As Landton suggests, you need to fit a Kev Mod or a Power Commander to get the air/fuel ratio set correctly for any air box mods.

BTW - What year is your XT and does it have an O2 sensor?

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