A mate had one, same colour (were there any other colours?), we went to the Manx in 1979 or '80.
Although it wasn't "sporty" styling, it had the 4-4 exhaust, he rode it like he stole it.
Came back after a lap with a story about racing, sorry "making progress", with a locally registered Z650 who really knew the course.
Chris said he really had to work hard to keep up - at Creg ny Baa he had to corner clipping the apex and praying for no oncoming traffic (open roads) as the front brake wasn't quite up to the speed. It was that or entering the pub bar at 70mph....
When they slowed down into Douglas, he discovered it wasn't a Z650 but a Z1000!
Lovely bike Bryn, health to enjoy.