I know with all the experienced harley riders in here you can figure this out.Alright, I have an 07 1200c and its all stock. All i done was drill a 1/2" hole through the center of the baffle. Now once and a while the idle gets erratic. One time when i let off the throttle its real low idle, then the next its real high. Then the check engine light came on. So i shut it off and waited awhile. When i went to start back up it was so full of fuel it smoked like crazy for a second. Also the light was off. I rode it back home the same distance and the light never came on,but the idle was wild again. Any ideas. Thanx

 

crankshaft position sensor...i dont know if the efi models have them..but the symptoms sound the same as when mine went bad..hope that helps

 

You did change the back pressure when drilling that hole. If your problem started with that, then it is a likely contributor, although to what extent is undetermined. With the EFI systems you need to have it mapped properly to get performance. Carb systems are a bit more sympathetic.

 

If it was working good before you drilled the hole. That's the first place I would look. Anytime you change something and it goes down the toilet, you go back and fix what you changed. IMO

 

Posted on here previously, was a procedure to force the ECM to recalibrate itself. That may be what you need to compensate for the exhaust change.

I believe it involved turning on the ignition and then CAREFULLY removing the positive battery cable for a couple of minutes. Then turning off the ignition and reinstalling the battery cable.

Maybe someone more familar with this procedure will chime in.

 

Can't say for sure on a bike's FI, but on a car that will reset the computer's data tables back to default.

There are basically 2 tables programmed into the EFI computers. A default table and a modified table. The default never changes values. The default table constantly changes values to accomidate for aging sensors, atmospheric changes, etc. When you pull the battery cable and wait for a while, the keep alive memory (including modified table) goes away. When the system is hooked back up the modified table looks identical to the default table for the first few minutes and then starts adjusting. In theoru, the ECM is constantly recalibrating itself all the time.

We did this on FI cars when we changed out an FI related component to a performance version of the same. That way the modified table would learn with the new component's data stream instead of taking forever to catch up by slight modifications all along.

I really need to find a good manual for HD FI as there have been a lot of questions lately and my only FI experience is with Ford EEC-IV's.

 

I know plenty of guys with EFI sporty's that have drilled the pipes and even replaced the pipes with aftermarket pipes and had no associated problems...I would haul the bike to the dealer and have them check it out. I think its just coincidence with what you have going on.