80 kz750 4 cyl power stalls on full throttle

I just bought the same bike, and I'm having the same issue, boggs down when I have it wide open and it started it out of no where, i have leaks in the carb boots which affects the idle and chock, but I don't believe that's the solution. I just got this bike a few weeks ago new plugs, carbs been jetted.
Have you figured out what the problem is?

Take a plug reading when this happens and start a thread on it. Pics too. :woohoo:
Steve