I've now had my 550 for twenty years. I had this problem when I got it & it was still doing it 5 years ago when I last ran it. When I say I had this problem, I mean the clutch would never disengage when cold.
The start up ritual every day was as follows:
Make sure the bike's in neutral.
Pull the clutch lever in.
Kick the kick starter 3 or 4 times until the clutch breaks free & the motor stops spinning.
Let the clutch out.
Turn the key on & fire her up with the starter. (Kickin' wears me out.
)
Pull the clutch in, engage 1st & off she'd go, all day without a problem.
Like I said, it's been like that since I got it, but clutch still fine all these years later. I've lost count of the number of oil changes since then of course. I figure it's just the nature of my old girl.