bad leak

i just bought a 77 kz750 and there seems to be a pretty substantial leak coming from the carbs or so it appears fuel lines have been replaced but still continues leaking any ideas would be greatly appreciated

If you mean gas leaking out the overflow tubes, it's a problem with the floats or check valves.

Kmalo86 wrote: i just bought a 77 kz750 and there seems to be a pretty substantial leak coming from the carbs or so it appears fuel lines have been replaced but still continues leaking any ideas would be greatly appreciated

Would first determine exact site of the leak.

Good Fortune!

if it is a vacuum type design the petcock will have a prime position instead of an off position. It is possible the vacuum controlled valve is not working correctly and is sticking open. I had this problem. I just moved the positions back and forth and rode it until it stopped. It didn't take long.

The 77 KZ750 is not a vacuum petcock, just a crappy mechanical valve that likes to leak like a mutha.