What it is:

One of the greatest bikes. Ever. Fastest production bike in the world when launched. Made large capacity and DOHC technology accessible. Staggeringly beautiful too.

Others in its family tree:

First conceived as a 750 - Japan got a 750cc model, the Z2. Only 30 or so Z Is (all black engines) originally made it to the UK: Z1Bs are more common. This is the root of Kawasaki superbike design.

It’s good because:

It’s an original: one of those once-in-a-generation bikes that moves everything on. And it’s still bloody fast today.

It’s bad because:

The chassis and brakes weren’t up to it, even in 1973.

Other Alternatives:

A Z900 or a Z1000 will be cheaper: and better to ride, but the Z1 is a true motorcycling icon, so what you lose in performance and ride quality is more than made up in sheer kudos