My buddy just bought 03 LE raptor and the pipe will begin to glow red after about ten minute of riding whats the deal? I have read about this before on here, but i don't really remember what was said about it.

 

A glowing header is a good indication that the bike is running too lean. He should stop riding that thing until he rejets it, or he could be looking at a hefty repair bill.

 

leaner is meaner, the more lean you are the more power you make. although you should go up a jet size.
but my bike is jetted perfectly and dynoed(perfect) my jetting is spot on and my header still glows every once in a while. no big deal

a little is ok, but i mean if it is extremely red, and looks like if you poked it with a stick you could bend the metal, fatten up your jets.

 

i let the shop jet my YFZ when i got my pipe. the pipe glows brite red at night. i dont think its a problem. just watch you legs, all my pants have burn holes through them and my leg does too.

 

I don't think that it's a problem cuz on my dad's YFZ his pipe glows red all the time and when we brought it to the Yamaha shop they said that it was normal so don't worry.

 

I guess it depends on the machine. I have to be running way lean for my header to glow bright red, but I have a smaller motor pushing exhaust through a bigger pipe. I'd do a plug chop and use the results of that to make a decision. If the tip of the plug is white you should consider rejetting, if the tip is tan you're fine.