Rejetting a 1977 Kawasaki KZ650

i was wondering im told that rejetiing my carbs on my 77 kz 650 is required cus of upgrades i made does that mean i just have to replace the jets onlty or do all other parts need replacing ex floats valve needles etc

If you put on an aftermarket exhaust or air intake then you likely need to upjet. That means only main and pilot jets. Definitely the main jets, likely the pilot jets as well (but not necessarily).