Short question......blue headers ecual to lean air/fuel??

[BigBoreSwede]

Hi guys!

Just a short question.........some would say blue headers are a sign that the engine is runnig lean. Is that true?


/BigBoreSwede

 

[jamesgs4]

it depends, if your pipes are thin-walled they will turn blue regardless.

 

[angus67]

ive heard-blue is lean, gold is rich. I rejetted a 1987 zuki intruder, and it had yellow pipes befor i rejet. I would have thought they would be blue, thanks to the EPA keeping everything lean. 400 miles, and they are still gold.\ prolly just a myth. Hey! maybe mythbusters would be interested in this!!
It prolly has more to do with the temps of the exhaust, since yams, and the intruder have double wall tubes. too hot=blue/too cold=yellow.

 

[sreimer]

Nice pipes and a nice clean looking tracker btw

 

[mseriously]

i always thought blue pipes meant pipes were just hot and possibly just a single wall pipe.

 

[cpt137]

single wall pipes always turn blue.

 

[5twins]

Yellow or gold is just the color before blue. It means they're not quite as hot. Yes, most single wall pipes are going to turn colors of some sort. If one side turns and the other doesn't or one side blues more of the pipe (longer length), then you may want to check for that cylinder running lean.

My pipes blued one side more (longer) than the other because I had a bad air leak at the head when I first mounted them. Both sides are blue probably because I started jetting from stock. My buddy's new pipes have only gone gold but we had the carbs rejetted and set up before we even started the bike.

 

[5twins]

I guess I should add that blue pipes can be a sign that you're running too lean. They don't absolutely have to mean that but they might if you haven't done a proper re-jetting. If you haven't worked your way up through main jet sizes to the point where you were too rich, then backed down a size or two, you may still be too lean.

 

[1974jh5]

BigBoreSwede, I like that fork brace! It looks like the Summers Racing piece I had on my XR40 Honda. Where did you get it?

 

[JP79]

off topic but how do you like the tires? Wondering how they handle on dry pavement and in the rain?

Nice Bike, I like the clean look man!

 

[gggGary]

Looks like the blue matches your handlebars and throttle. Cool!

 

[hotdog]

If your pipes go blue it is not an indication of rich/lean mixture, Air cooled boxer twins go blue if you let them idle for too long, just getting too hot.

 

[cpt137]

Mine are blue and running way rich by the plugs, I have just decreased the jet size. Blue is hot, you have 1000 degree gasses coming out on those pipes. Rich and lean can only be determined by plug readings.