I am new to the whole 4 stroke world but this doesn't seem right. I have an 04 WR450 absolutely love the bike but I have noticed when warming it up. The header starts glowing?? It doesn't happen while riding just when its sitting idling. Is it running too lean? I have put all mods on it and it seems to be jetted right the plug has a nice tan look. It doesn't hesitate or bog out. I just have never seen this before. Anyone else out there with this issue??