Topic: discolored pipe chrome

[That 70s Bike]

CB750K6 completely stock.
#1 pipe was a little gold from heat when I got it from the P.O. (2-4 are bright chrome)
He claimed the problem (carb) had been rectified by the Honda dealer.
I think it's still questionable/getting worse. I need to review the factory service manual.
Could I make sure it's not lean without removing carbs, via the float bowl- check jet(s), emulsion tube, etc? or remove tank- check needles? Thanks

[ekpent]

Does the spark plug show the signs of running lean.Put a new one in and check it after a bit. Also touch all 4 header pipes with a wet rag and observe the 'sizzle' and see if #1 is more pronounced or check them all with one of those cool thermal gadgets. Did the PO ever say what the pro's did to rectify it ?

[That 70s Bike]

I checked the plugs when acquired, but should check again.
Thanks for the wet rag tip, I don't have the thermal gadget.
No, the PO just said the local Honda service dept had "addressed" it.

[KingCustomCycles.com]

Burnt valves will do that, as the fuel excapes, it ignites and heats up the pipe.