Originally Posted by nidyanazo
The change in color is normal.
To see if it's running rich, do a plug chop.
That's where you run the bike at full throttle (or part throttle, whatever rpm range you want to check) and then kill the motor.
Pull the plug and check if it's dark and wet (rich), white and burnt (lean), or just right with a nice brown tint/
Good advice - 'cep ya wanna let the motor cool down before trying to remove the spark plug as you may pull the threads out of a hot motor