Crikey, I had one of those when I was 20 (and that is 30 years ago...)
Great bike, a bit top heavy but handles sweetly. Keep an eye on the front brake as they tend to seize and need a regular clean but be very wary of the bleed nipple as they also seize and will snap off even if you're being gentle.
I also had the 550/4 which I thought was a far better bike...