Black or burnt valves - What am I looking at?

[BlomC]

Edit: Changed the title for future "searchiness" relevance

I opened our new beast...

Can anyone tell me what I'm looking at please? Burnt valves or something? Can this typically be caused by wrong valve clearances?
Should I be worried? :-[

There is black marks in the throttle body venturi's at the butterfly valves - these I were able to wipe off with a cloth - greasy oily type paste...

 

[BlomC]

 

[spankme]

 

[spankme]

 

[BlomC]

 

[BlomC]

 

[Cracker]

 

[BlomC]

 

[Cracker]

 

[BlomC]

 

[alec]

 

[BlomC]

 

[morne950]

 

[Cracker]

 

[BlomC]