Carbon Deposits In Cylinder?

[Togger]

 I was adjusting my valves and used the straw in the spark plug socket to know when the piston was at TDC. After I pulled the straw out the end was covered in black deposits. Is there a way to clean that out by running the engine?

[Ruffus]

@Togger, any combustion motor (particular one-cylinders) have a certain amount of carbon residue within cylinder head. Don't worry about. Only if your sparkplug is completely sooty black and oily-smeary, than your fuel mixture is too rich. Running on idle causes even with correct mixture a sooty plug.
And yes, by driving the scoot the plug reaches a temp of appr. 400 °C and cleans itself from this soot.