I installed the VIED's on my nightster last week. I had it turned/tuned to about 13.8-13.9. But was thinking that since I didn't have aftermarket exhaust, just drilled out stock baffles on stock mufflers, nor do I have a hi flow intake that I should tune it back closer to lean.

I tuned to 14.3. And started to get decel pops again.
Should I tune it back to richer?

 

Decel popping is due to unburned fuel igniting in the exhaust. By richening it up, you can get rid of this because the excess fuel cools the air and changes the ratio in the exhaust so it is not conducive to igniting. You will still have too much fuel, though.

The major causes are rich AFR, and leaky exhaust gaskets letting fresh air in. Check to make sure you don't have any exhaust leaks, otherwise 14.3 is a pretty good AFR. You don't usually hear it with stock bikes because the mufflers do a good job and reducing the sound.

 

Thanks scuba that was very informative. I guess I'll leave it where it is for now then.

 

I think that by taking out the baffles on the stock muffler, you have reduced the back pressure. You should really mod the air cleaner now, to balance out the airflow. There are excellent instructions on the forum from mreed for building your own higher flow air cleaner for less than $50.

I am running the XiEDs at 14:0 on stock exhaust and air cleaner, and the performance is already much improved. No noticeable backfiring or popping.

This weekend I will replace the mufflers and the air cleaner at the same time. Hopefully, the intake and exhaust will still be fairly balanced, and the XiED will keep the mixture right.