hello, i have a 77 cb550k that has been sitting for over 20 years. i got the bike running and it felt very sluggish. every once in a blue moon when i ride it i would hear a popping sound and then a surge of power. it wasnt a bad popping sound but when i pulled the plugs out i saw the #4 is black and all the others are light brown. im getting a spark, the carbs are farely well synced, im assuming its a fuel problem, where do i go from here??
