Either save up for or buy a decent bike. I rode a GPZ750 and it was a piece of crap old tech that doesn't handle. It'll keep breaking down and will drive you nuts finding parts.

Don't listen to any of these "ahhhh those were the days" posts on this forum from people with nicknames like 'spanners', 'spud', 'mad dog' or 'Nob' who like to pull things to bits all weekend rather than ride the bloody thing.

It's probably the only way they can escape the ball and chain by locking themselves in the shed all weekend fiddling with their shitty bikes.