Motorcycle Repair: Engine dies when Choke is turned off, vacuum leaks, air leaks

Question
I have a Suzuki 1987 zx600, the motorcycle starts fine when I have the choke on. As soon as it is turned off, the engine dies, even though I know its warmed up. What could be wrong?

Answer
I'm confused here... Kawasaki makes a 1987 ZX600, not Suzuki.

Kawasakis have a vacuum operated petcock that has a diaphragm that can fail, causing air leaks and restriction of fuel flow.

The Intake manifolds may have cracks in them causing air leaks.

You could have water/debris in the carburetor float bowls.

Be sure that you have even compression on all cylinders, then be sure that you have good plugs and proper spark timing on all cylinders. Check all air intake connections for vacuum leaks, including vacuum lines to any emission system components.

If the muffler has been changed, the carburetion may need rejetting to compensate for the change in back pressure.

Bill Silver