Yes still catching with clutch plates removed
catching from the crank or back wheel motion? if you could pull the clutch basket off you could tuern the layshaft and mainshaft independently although I'm not sure what that would reveal .
The primary shaft on these (
unlike the z900/1000/1100 series where it is mounted on the side of the crank)
usually fails by slipping on the starter motor. Very unlikely but does the starter motor turn when you move the crank? if so possible primary starter clutch problem..
Take the spark plugs out, turn motor by hand and 'feel' where it is catching somewhere - between the crank, primary chain, primary drive shaft/clutch basket drive gear . If doing this for the rear wheel causes the same I guess both your gear shafts are stuffed. No probs, they are two a penny cheap for 550's.
Drain the oil and drop the sump will let you see some of the gearshafts. If you need to strip the motor leave it in the frame for now - the clutch centre and primary shaft nuts, (which you need to loosen when splitting cranckcases) are very tight and much easier to loosen in-frame.