Brown Near exhaust flange

[engine22]

Got my new exhaust set up and it road tested wonderfully. However, there is some brown forming around the headpipes near the flange that hooks to the head. Can't find any info on this. Anyone know what causes the brown? Is it something I should be worried about? I can post pics if that would help.

I have read that brown/yellow/gold head pipes might mean too rich, but this would not make much sense as I just installed an aftermarket exhaust.. Could it mean too lean? I just installed mikes commando system, and I believe its a single wall type, so does that mean the head pipes are going to turn different colors regardless?

Thanks

 

[angus67]

they are going to turn colors regardless because of single wall. the stockers a dual wall, so they keep a nice chrome shine to them. i kinda like colored pipes.
They are varied arguments about what the colors mean. Ide always heard yellow was rich, and blue was lean. many peeps are on both sides of the fence on this.