reading valve color for diagnosis (pic)

[gidaeon]

I am replacing my gy6 head and I was wondering if the color of these valves "tells a story" regarding mixture or any other health stats? I just assumed though both valves would closer in color but I guess it makes sense exhaust would be dryer\hotter?

Right I am uni oiled filter, stock jetting and the plug is totally fouled but power was OK. I tried upjetting and is bogged horible.

Does the coloring you see mean anything? I am on the fence about replacing piston and rings. I assumed my terrible blueish smoke was due to bad rings but maybe it was because the exhaust totally broke off duh..

[scjeep4.7HO]

Not sure how "clean" these usually run but a pretty good amount of build up. Either too rich, plug needed changed, poor compression (should have checked it before pulled apart) dirty air filter.

[ckau]

A few things I can see here. The combustion chambers doesn't look too bad, I've seen worse. The build up of carbon is mostly at the exhaust side. Shows a slightly rich mixture but it's better to run on the rich side. The build up also indicates a incomplete burn of the a/f mixture. Using higher octane or a fuel additive to promote burn can help. The biggest problem I see is "blow by" at the exhaust side of the head gasket. The exterior of the head is blackened from leakage from either the gasket or the exhaust pipe. I suspect the gasket because there are obvious signs of pressure leaking at the cam chain opening below the corner stud. Check your crankcase vent!
Some stuff I do to insure a solid seal on the head gasket:
Grab a sheet of glass, 12" square is good, the thicker the better. I use a piece of 1/4 tempered glass. With some contact adhesive lay a sheet of 600 emery cloth on the glass. Gently slide the gasket surface of the head around on the sheet to clean and flatten the head. High spots will show up shiny first. Gently slide around till the whole surface is shiny Don't force or push down on the head, you'll just create a uneven surface. Do the same with the top of the cylinder jug. You'll get two machine surfaces that will reasonably mate together without highs and lows. With a more aggressive paper along with time and patience you can effectively shave a thousands or more off the head to slightly raise the compression ratio.
Spray/coat the gasket with aluminum spray paint. Aluminum spray paint consists of particles of pure aluminum, allow to dry! This gives the gasket a sealer of sorts and promotes bonding to the head and jug.
I'll tighten in three stages. hand tight to make sure everything is seated. then 8ft/lbs in a x pattern then final at 14 ft./lbs.. The final tight may seem low according to some specs but with the mating surfaces matching and the gasket paint to seal I don't have issues plus it doesn't strain the case threads and the studs don't twist as much. Take the motor through a couple of heat and cool cycles then re-torque. Check torque after a couple hours of ride time. I found using this technique just about eliminates head gasket failure

[SYCARMS]

Run your finger in the exhaust port, if mostly dry and powdery it is from fuel, if sticky or gummy it is from oil. The blue smoke you mentioned is from oil burning, fuel will be gray to black out the exhaust if a rich mixture.