Oh boy... Working on the carbs sounds really intimidating and I'm scared I'll just screw my bike up even more!
I changed the oil and it was completely black... It was the first time I changed it since I bought it from its previous owner.
Good job changing the oil....hope you changed the filter too.....
Anyway, if you haven't dipped and rebuilt the carbs with new o-rings, it's something that 99 times out of 100, absolutely, positively needs to be done. It's looks quite intimidating when you first look at it, but, in actuality, it's not bad at all. Just stay organized and follow the tutorial to the letter. Be very careful when removing that float pins as not to snap the posts. Get your orings from cycleorings.com and follow the tutorial below. After your done, do a bench sync and slap them back in.
http://www.thegsresources.com/gs_carbrebuild.htm