As the wise Einyodeler says, get rid of that o-ring chain. Believe me I learned the hard way! Saltlick, the difference between a regular chain and o-ring is the overall thickness of the chain. O-ring chains are wider cuz there are o-rings between the rollers. Youll see em if you look. Since the 0-ring chain is wider it will rub against your engine case because the clearance between the front sprocket and engine case on our bikes is very tight. Just get a nice standard 530 chain. I recommend EK chains. Tsubaki chains suck! Also I dont know where you live but either its quite warm or you are way rich to be starting and idleing w/out choke. Im pretty sure you have the same carbs as me which means when you set the choke it doesnt pull the throttle as well like newer models. So yeah, way rich. Try turning those pilot screws out a bit and you may be surprized. Good to know the bike is in the hands of someone trying to make it nice again! Rock on.
Tomfl57: That actually depends on what year your 550 is as far as which way to turn the pilot screw. Heres an easy rule of thumb for any set of carbs. Well old ones anyway. If the pilot screw is on the air filter side of the carb then it meters air. So out to lean, in to rich. If the pilot screw is on the intake manifold side of the carbs(front of the carbs towards the cylinder block) then it meters fuel. So the opposite, in to lean out to richen. Later guys.