04 XL 1200 C Failed Emission Test

[Tolebarn]

Bought the bike just over a year ago with 41K miles on it.  Took it back to the dealer one time because it seemed to be running rough and smelled rich while sitting idling.  They said the front plug was fouled and the carb idle screw was turned out too far ("more than two turns").  Six months later it smells rich again and won't pass emissions due to high CO.  Carb idle screw doesn't seem to make a difference since I can bottom it out and the engine idle doesn't change.  I cleaned the plugs just to make sure and turned the idle mixture screw 1 complete turn in and the numbers at emission testing came back the same as the first time it failed.  Any hints on where to start would be appreciated

[Princess Butt]

Did someone change the slow jet inside the float bowl?

That's where I would look first. Since the mixture screw is non-responsive, it's probably getting so much fuel that adjusting the screw doesn't matter.

Also check your float height.

BnEUC

[wreck74]

If you have an intake leak, the mixture screw won't make a difference when turned in or out. The engine should die when you run the screw all the way in.

[blackhillsken]

If he has an intake leak, the CO will be low and the HC will be high.  Sounds like the opposite (too much gas and not enough air).

[BONERACIN]

Check and make sure intermediate jet isn't loose or maybe laying in the bowl?