1) Have to adjust the idle screw in for it to idle well with choke off when starting a cold engine. After it warms up and I ride it a bit, I have to back off the screw to get a lower idle or it is idling high when not in gear(stop lights or neutral).
The idle speed is adjusted with the engine at operating temperature. There is no fast idle cam linked to the choke. So, you have to hold the throttle until it is warm. The 550 does not need a warm up. Suit up, apply choke, start and go with just enough choke to keep it going. Your hand on the the throttle can keep the revs up during the warm up ride. And, you can reach down and incrementally to remove some choke a bit at a time. After a few blocks of driving, no more choke is needed and the engine should be warm enough to idle at the setting made when it warm for adjustment.
It's one of the bike's quirks you adapt to.
2) After the engine warms up and I have been riding and adjust the idle back down with the thumb screw to a nice 1000rpms then it seems to not want to go into neutral. Keeps clicking past it. When I first fire it up though it goes into neutral quite easily.
This is a sign of a dragging clutch. If it does this with new oil, and the clutch adjusted properly, then you have warped clutch plates, nicks in the clutch basket, or the bike doesn't like the type and/or viscosity of the oil you've selected.
Alternately, you will find it easier to snick into neutral with any motion of the rear wheel. Either anticipate going to neutral while the bike has some motion, rock the bike fore and aft while applying a little foot pressure on the shifter, or work on the clutch 'til it operates as you wish.
3) Some times at after coming to a stop the motor will rev a little high until I let out on the clutch a little just about to the friction point then I can pull the clutch back in and it idles just fine where iti suppose to .
Either the carbs need sychronizing, or the carb couplers are leaking air.
How can I tell when it is time to get a new chain /sprocket?
When the pins in the chain have worn or there are tight spots felt when the chain is in certain positions on the sprockets.
If you can pull the links away from the sprocket an 1/8 of an inch, a new chain is indicated.
Worn sprocket teeth start to look more like hooks than a symetrical tower.
Avoid oring chains for that bike. The sprocket is too close to the engine case to allow for its extra width.
Cheers,