1980 KZ750 new owner some help be great

Okay let me say love the bike been rider for years had many bikes new to this one though.....so I bought this bike it's converted to a bobber...here few things need help with its open pipes and has pods on the carbs he said stage 3 jet so I fire this bad boy up and it only runs with choke it has diff gas tank so no petcock and the three vacuum hoses have triple t to all them....Also I'm getting low commpression reading of 100 psi on all cylinders which makes me wonder how it started up and idles good on choke and it dont die with throttle....so can anyone please give me little advice on were and what I should do from here I have experience fixing engines and little with carbs so shoot I'll get it...Also one more thing we're is the air fuel mixture screw can't find it thanks for your time...

koloj, first and foremost welcome to the forum. Your bike is certainly a custom effort which means more factors come into play between stock and aftermarket parts. I found a wealth of information here on the forum by just looking around and running searches, jumping on a few discussions and then working in my shop.

I think it would be helpful if you posted a few photos and made a check list of what you know about the bike, what is stock and what is not running correctly. And from there I have a good feeling some very experienced folks are going to jump all over your project and help you out.

Thanks for reply and guess what so after reading a little and doing leak down I decided to take right cover off goto top dead center and bingo piston 1 and 4 valves open so looked make sure piston was at top cyclinder and was....so from here I took off the valve cover guess what no clearance on any of the valve except one at top dead center....so going on from here being sure I'm right do u check the clearance when cam valve engagers are facing center at each other or away from each other check both ways by the way...Also where do I find the shims at best place ...and how do I go about doing a good valve job untorqe the cams and tourqe them to specs check again and pepole are say many diffrent clearances what should I have them all set at thank u...

Is the bike a 750-4? I'll assume it's a KZ750-H1 Ltd (bobber modified).
Did it run right when you bought it? Any idea what brand of "Stage 3 kit" he used & exactly what parts he swapped out? (ie, main jets, pilot jets, jet needles). By any chance did the po give you the leftover stuff?

Vacuum ports. Each carburetor should have a vacuum port. I would cap each one w automotive vacuum caps. One of them is probably already capped (carb #3).

Air mixture screws. The air mixture screws (pilot adjusting screws) are probably hidden under metal plugs at the top of each carb (note rounded bulge on each carb).

Carb jetting stuff. I would assume the po didn't know what he was doing & check the carburetors to verify what's what --- main jets, pilot jets, polyester caps in place, jet needles clipped, etc. See the parts diagrams at Kawasaki.com or Partzilla.

CVs + individual filters. It seems worth noting that CV carburetors can be difficult to tune for pod filters. In general it's easier to get the bike running in the stock configuration first, then make the airbox & exhaust changes. I would install the stock airbox & some mufflers to get the thing running, but that's just me... opinions vary.