Got one exhaust header turning super blue

[G-Gaurd]

I've been taking out my xs400 every couple of days and running her around the block . Today I noticed that one of my exhaust header is really turning dark blue and the other side is looking normal .

Is this a sign something is wrong ?

I just got the bike up and running and I haven't put more than 10 miles since she started ...

Any and all advice is greatly appreciated .... I don't want to take it for a ride and the motor blows up

 

[BBS360]

Probably running too lean.
I'd have a look at the plugs. Compare to each other and the photos in the Haynes manual.

Stock exhaust and intake?

 

[Jeff0133]

Running lean thus hot...

 

[G-Gaurd]

Yes all stock. ... Pulled the plugs that are brand new .... One was all black and oily .... The other looked almost new .... That was the one from the blue header .... Hooked up my inline spark tester .... Turns out only one coil is firing so I'm gonna leave the carbs alone right now and find out what's wrong with my coils

Once I got both coils firing I'll look at the carbs