Im gonna to beat my CVs with a ball peen hammer

Yeah so, its been a couple of weeks, and im still trying to figure this out. ’81 Kawasaki KZ 750 LTD. Damn CV carbs... I tore em all down again, soaked each one in carb cleaner for 12 hours, blew out all the channels and ports. Good flow, no scaly build-up, carbs look brand-new. Slides move up and down freely, you can hear them suck and blow as you manually move each slide up and down. I even notched the air filters, in order to give full air flow to the kidney bean-shaped port in the opening of the carb, which allows the outside pressure into the top of the carb, which raises the diaphragm. Everything is looking great on the carbs, all clean. Except for the fact that the air/mixture screw in carb #4 broke THE FUCK OFF! its just the tip of it; the needle, but it is jammed in there tight. The rest of the air mixture screw backs out fine, with the spring, metal washer and o-ring. But the hole that the needle part goes into which opens into the venturi of the carb is completely plugged up by the broken-off needle of the air mixture screw. I have tried applying heat to it, dropping it in the freezer for a few hours, tapping it with a pick(from inside the venturi, since it is conically shaped and that is the only way it can go), and any mixture of the three, but i cannot get that piece of the brass air mixture screw to come out.
I gave up on the individual carb a week ago and went looking for another carb to replace it. I thought I found one; all the jets fit right up, slide, diaphragm, needle all fit good. BUT, the opening of the carb which actually goes into the engine is a millimeter bigger, and it seems the whole carb itself is just a hair larger: the choke plate holes wont line up, the 2 brackets that hold all 4 carbs together dont line up, and the #4 carb itself wont fit into the carb holder (without jamming it in there, after which it just pops back out). Now, I could modify the brackets, choke plate and carb holder to allow that 4th carb to line up ok, but it would be be kinda jimmy-rigged, and I’d rather keep things legit on this whole setup. So, any ideas here? Any suggestions on how to get that piece of the air mixture screw out of the carb? I even found a nice set of mikunis that I would be willing try out except that they dont line up right with my carb holders. What sucks the most is how close I got on the carbs, theyre spotless, everything working great, spent good money on new jets, gaskets, etc., and now the whole thing is fucked because one air mixture screw broke off. Whatever you got, Im listening...

Carb Repair Technique

Stop-Stop-Stop...
Those are CR's he's smashing... Damn you Ed.... :laugh: :laugh: :laugh:

Before tossing the carb, might consider possibility of drilling out the broken tip from the orifice.

Could measure orifice diameter on an undamaged carb, using the chuck end of various sized drill bits, until finding the most feasible slightly smaller size.

If available, would opt for a bit with reverse thread.

Good Fortune!

Got a picture of the broken screw next to a good one? That will show how much is left in the carb body. Patton has the best suggestion for drilling, left hand bit if there are any threads on the broken piece.
I had one that was stuck, not broken on a GS, I drilled then easy outed while heating around the casting area of the carb with a Butane pocket torch. Lots of penetrating spray, the after a few days of this it backed out. Got to be real careful not to damage the threads or the tappered seat.
If it is just the tappered tip with no thread left on it, the small drill technique might work. Maybe make up a sort of small tip prying tool, to go into the carb bore and apply upward pressure to the needle tip? Using a protective sleeve or something where it contacts the bore's throat?

You are talking about the very very very small tip of the needle?

I had that happen on a set of carbs I got in a lot i bought. Took a thimble with a pin cut off and stuck in it then using big magnifighy glass to see. Old ya know held it in there and pushed down . only took a hunderd trys and many beers.

Is the tip of the broken adjuster protruding from the orifice into the carb bore?

Is the tip of the broken adjuster recessed into the orifice in the carb bore?

With a section of a sewing pin or needle that's smaller in diameter than the orifice, is it possible to hold the pin with needle nose pliers and get it correctly aligned into the orifice from inside the bore, and push push push?

What about fabbing some manner of pushing the pin by using a C-clamp inside the engine side of the carb bore?

An L-shaped dental pic might also be helpful.

Just thoughts.

Good Fortune!

Yeah, its just the very very tip of the air mixture screw, just the needle part, maybe a 1/4" long. Ive tried all of the above. Using a right-angle pick, needle-nose pliers holding a pin inside the bore of the carb and trying to push it out. Nothing. Initially, part of the needle was protruding into the bore of the carb, but after working on it so much, its worn/broke off so that its flush with the inside bore of the carb now.