Bike is a '03 YZ450F Supermoto Street Bike I started the YZ and let it idle for a few like I always do. I went for a slow ride. I wasn't hammering it at all. All of the sudden, my head lights flicker and then go out. I still had my tail light. So, I ride a very short ways to a well lit parking lot. I got off the bike(still running) and noticed the header was glowing red. &%$#@!??? I turned it off and the header immediately quit glowing. I have been meaning to jet the carb which I think is running lean. It does pop when throttle is off. Would that cause the motor to run hot enough to light up the manifold? Is that considered overheating or just running hot in the right place? The oil is full as well as the coolant. Any suggestions?