Red hot header after rejet

[built4thetrack]

I just rejetted my 2009 YFZ 450, and I've got to say, I'm a bit concerned. After letting it idle for just a short while, I noticed the header pipe glowing red! That's never happened before the rejet. Is that a normal thing, or did I screw something up with the fuel mix?

 

[Y0nko]

A glowing red header pipe usually means its running lean, especially after a rejet. It's not normal and can damage the engine if left unchecked. Check your jetting, especially the pilot and needle positions, sounds like its not getting enough fuel at idle or low throttle.