I have a 2003 raptor with a fmf power bomb header and a white brothers e series and the proper jettin and it has run fine for the last 3 months and now i start it and run it for maybee 3 minutes and the head pipe turns cherry red. and i figured it was runnin lean so i checked it for air leaks and stuff bt the plug reads just as it always has.

 

Thats the beauty of a stainless headpipe man. they glow a bit.

 

it has never done that though and i have had the head pipe for months

 

HMMMM and the thing is still runnin strong? I wonder then if the stainless pipe thru a series of hot n cold cycles gets the molocules realigned so that it absords more heat. ? i dunno. i know my brothers warrior wiuth stainless headpipe always glows and he is a lil on the rich side. dont touch it [img]i/expressions/face-icon-small-wink.gif[/img]

 

it runs mint and the rest off the motor dosent seem to get hot.just the header pipe.

 

i know a car will do that if the cat is plugged up and we did some mud riddin im gonna check and see if my e series is plugged some

 

When the air is hotter it is leaner with oxygen. What size pilot jet do you have? I suggest a 27.5

 

my car glowed the header pipes when the power valve stuck and was dumping fuel at idle. Rich can also cause it. Maybe there is trash in the carb making it flood a bit.

 

my raptor has never done that but my buddies new 450r does that all the time...he siad it has always done it ...I'm stumped man..wish I could help.[img]i/expressions/face-icon-small-frown.gif[/img]

 

My completely stock, four week old YFZ does the same thing. I too was very concerned the first time I saw it. I did a search on this just last week. Seems it's quite common.

Buck