I need help!!

I have an '82 KZ and it's given me a lot of problems with the carburetors. I took them to a mechanic who promised to give them an ultrasonic cleaning, but he never solved the carburetor problem. When I opened the carburetors myself, I realized that he hadn't even given them away, and it's quite likely he hadn't opened them either because they were full of scale inside. I also realized that I removed the air jet that was swept out with a drill bit and put a screw in to try to compensate for that air leak.I've adjusted the carburetors as much as I can, but it only won't run if I set it too high; it starts to overheat, and if I set it too low, the engine starts to run slowly until it stalls. My heart races like crazy, I'm drowning. I've been like this for over two months and honestly, I'm starting to get discouraged.  

Oh, my.

Is the mixture screw still in place where that long screw is sticking up? The mixture screws have a long, tapered end that comes to a sharp point. It is number 16014 in the diagram here--  www.partzilla.com/catalog/kawasaki/motor...retor-parts-kz650-h2
Those screws are absolutely crucial for idle and low speed operation. Please note that there is an oring on the screw that prevents any leakage around the threads. If the drill went down into the area where the tapered part of the screw lives, that carburetor may be unusable.

Also, I see no air filter or filters in place. The factory air filter system is best. Those carburetors are constant velocity (cv) design, and are very, very sensitive to intake air volume, velocity and turbulence. They can be tuned to individual filters (called pod filters in the U.S.), but it is very difficult to get them to work well with no filtration at all.

All of those vacuum hoses with screws in them are a potential air leak. They should be replaced with proper, tight fitting, vacuum caps.

I think it would be a good idea to completely disassemble the carburetors and carefully inspect them to see if they are useable. If so, then they should be carefully cleaned (you do not need an ultrasonic cleaner to do that) then put them back together and adjust them. Normally, the only parts that need replacing are the soft parts - gaskets and orings. However, careful inspection may reveal some hard parts (jets and needles and such) in need of replacement. Genuine Kawasaki parts are best when available. If you need some part that is out of production, please ask here before buying substitutes, as some of the stuff online is junk and will introduce all new headaches.

Carburetors seem intimidating, but there are lots of skilled, helpful people here who can walk you through the process.

Muchas gracias por tu respuesta. Ese tornillo ya no tiene la boquilla de aire en su lugar; la reemplacé con el tornillo. Actualmente estoy planeando comprar un macho de roscar para crear las roscas. Pero ten cuidado con eso. Con la sección cónica que mencionaste, por suerte tengo filtros de aire separados, así que los probaré sobre las mangueras. Solo lo descubrí cuando puse esas mangueras, pensando que funcionaría. Fue pura coincidencia, ¡y funcionó! Cada vez que se sueltan, el motor se revoluciona como loco 😅 Compraré los mejores, compraré los tapones de vacío tan pronto como pueda, haré algunas pruebas con los filtros de aire y te informaré pronto. 

The missing screw will look something like this

ae01.alicdn.com/kf/HTB1kLCjKFXXXXbtXFXXq...R-CB-1-GR-PD26JS.jpg
 

Okay, I'll try to find a place near where I live so I can buy that. Thanks for the help. I've already got the filters, so I'll be testing several things this week. 

A Kawasaki dealer will likely be the only local choice.

Might i suggest just buying another set of carbs of known quality. You've got a lot of bad things going on from first glance. Things from the sound of it, you're not equipped to do successfully. One big thing is screwing that bolt into the missing mixture screw hole. The original mixture has really fine threads, .5 or .75 pitch, can't immediately remember. Once those threads on carb are corrupted you'll never get a correct mixture screw to fit. It CAN be done but you need the correct tap and procedure to do it. Yes, they have been baking in an ultrasonic machine. Discolored castings and rusty. If there was "slime" inside the bowls, they were just thrown in the machine whole. This does more harm then good. Good Luck though! 

That's really one heck of a picture.

I have thought about it, but the prices make me consider fixing the originals better. $1400 for new Mikuni parts, for me being in Mexico, is like buying a new motorcycle 😬 I will do my best to compose them

I'm actually considering asking around at dealerships if they have any carburetors lying around, just out of pure luck, since I've seen some KZ1000s there at the dealership. 

1400USD for parts? Maybe lost in translation but i was talking about getting a "used" set, not brand new. KZ1000 carbs won't be compatible with your 650 BTW, completely different even though they look "similar" from the outside.   

Just a quick glance over at ebay, found a couple sets of the 32mm sets proper for Your 650. FYI, KZ1000 similar are 34. And NO, it won't go faster with the 34's ha.     Still need a bit of final go-thru but look 1000percent better starting point then what you're dealing with!