Hello Kawasaki Forum, as a newcomer in the forum I need your help, because my Z750 Sport, Bj 84 (KZ750E-L4) is not running properly. I have installed new spark plugs, new intake nozzles and air filter rubbers. The air filter was also changed. On this occasion I completely disassembled the carburettors (Mikuni 34), cleaned in the ultrasonic bath and provided with new o-ring seals and float needles – the carburettor was already resinated by the service life. I did not adjust the synchronisation screws of the carburettors. The membranes of the sliders are fine. Had also removed the idle screws (top of the carburettors). I turned them out with 5 half revolutions from maximum screw-in. Symptoms: Kawa runs well in idle – I don’t need to pull the joke out to the second position at all. As soon as I give more gas the engine starts to stutter a I can’t drive it anymore – I can’t take any more power. Had already noticed that the air hose, which goes from the 3rd carburetor into the air filter box, has a small metal nozzle in it. What function does it have? Does it equal the vacuum in the carburetors? I had mistakenly replaced this air hose with another (without a metal nozzle) with the effect that the moped nu r ran on three cylinders. Now the original hose is on and I have the phenomenon described above. Can someone help me further what it might be. Also in the workshop manual I found no information about the adjustment of the idle screws. I suspect that the adjustment of the idle screws does not fit. Could it also lie on the ignition coils? I had disconnected it and removed it. Furthermore, I still fell for the rev meter to “jump”, although the engine rotation As a hobby screwdriver, say thank you for your tips.