Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
With the CB750 definitely put the engine on its side and lower the frame onto the engine, I'm pretty sure the same method is best for the 550.
Is it easier to wait until the wheel is built and then change the bearing Mike ?, I don't know if the 550 is the same as the 750 but on the 750 the retaining ring is centre dotted to lock it in position, I took a fine drill and drilled out the centre dots , I'm not sure if there's another way but someone will say if there is .