I had your bikes little brother in 1974.
Mine was a Blue 380 Suzuki 3 cylinder. It looked very much like your 550.
It was the smoothest bike I ever had until I got my 75 Goldwing.
It didn't even have an electric starter because you could kick it over with your hand.
I sold it to a guy who was tired of always having to work on his Harley.
He had it for two weeks before it got away from him and he layed it down.
I really enjoy seeing the old bikes making a come back.
I've noticed a lot more nicely restored Japanese bikes this year than I've seen in the last 5 years.
I hope the trend continues.