Adjusting my brother's 2008 nightster 1200...

[ERM83]

This is the first go for me on an EFI bike. He's got slight popping on warm-up, and it'll occasionally do the "CCHHHH *drops out for a quarter second*" deal. I'm not savvy with the efi, and my bike does this occasionally as well (carbureted). What is that symptom?? Air / fuel, or timing??

[XJOK2PLAY]

This is the first go for me on an EFI bike. He's got slight popping on warm-up, and it'll occasionally do the "CCHHHH *drops out for a quarter second*" deal. I'm not savvy with the efi, and my bike does this occasionally as well (carbureted). What is that symptom?? Air / fuel, or timing??

This sounds more like an issue with the stock ECU's fueling map, to me.

The Kawi C14's had similar issues, both solved by a man named Steve in Sunny Florida who built his own ecu flash, and has since flashed hundreds of C14 owners bikes... mine included.

I installed an aftermarket exhaust. This enhanced decel popping.
The C14 had some inherent flat spot issues at certain rpm's.
Since flashed... Not only are those gone, but now the power is linear, like a rocket... all the way to redline.
Bob