"Choke on, cold bike, unburned fuel and fresh air injected directly AFTER the exhaust valves makes for a glowing red pipe after a few minutes."

I have had red glowing head pipe on a totally stock engine under these conditions. Stock jetting means that you need to let it sit there running with the choke on for several minutes before the choke can be shut off or else the engine will stall. On a cold night this last winter, the low light conditions made the glowing very apparent.

It went away completely after dechoking.

Bottom line is that most modern bikes will have glwing head pipes under normal conditions. We have an annual night enduro in August where we race in the dark, really cool, and during that event there are many glowing pipes to be seen.