GPZ carbs

So I just purchased a real frankenstien kz750 slash gpz 750. Its a kz L3 frame with a gpz motor. It runs like crap so after cleaning and checking the mains and pilots its running 36 pilots and 118 mains. So I put my 81 kz 750 e carbs on it and it ran perfect. So my question is are the gpz carbs a different mm carbs? I bought 125 mains for it the same as the kz carbs have. Hoping that helps.

The GPz750 uses Mikuni BS34 carbs.

The BS34's have an enricher, and no choke plate in the airway - the 750cc horsepower wars were in full-force, and they wanted to flow every bit of air they could.

Mikuni BS34 did come on gpz750 and some models of kz750 and kz1000. Difference in main jet could be because of a completely different needle shape / size.

Guessing that's the problem they are keihin carbs

Keihin and Mikuni use completely different jets. You can not compare jet sizes between them based on the numbers.

Stock jetting and pilots have worked prefect on mine both with & without a 4-1 pipe on it for 32 years. Just backed the mixture screws out 1 turn more for the pipe. Don't just clean the jets, clean all the passages on the carbs too. Theres an excellent cleaning diagram on here but I don't recall who wrote it