1982 Kawasaki KZ750 LTD Hesitation When Engine Gets Warm

wrote:

I actually forgot to try it the other way around, I'll try introducing an air leak tomorrow when I get the chance to.

As for the carb rebuild offer, I'm really hesitant to try and use the original set vs. the set off the F bike. The original set has a hole drilled from the bowl straight into the throat of the carb in the number 1 carburetor. I think number two had a crack or something repaired with aluminum weld. Then on the "plugs" that are supposed to be there, three out four are missing so someone tapped the bottom for set screws and used that for plugs. Now I think that the set screw idea probably would work fine if there wasn't some other unknown issue with them.

I guess I want to ask if there's any advantage to rebuilding the messed up original set vs the clean set from the F bike?

Wow, it sounds like the original set is F'ed up pretty good.  Think your idea to switch out to the F set is a good call.  I'd like to encourage you to fully break them down and clean them properly.  Make sure all the small passages are clear, particularly the pilot passage and so forth.  The stock jetting is set up for using an airbox so realize that in advance (no pods otherwise you need to rejet.)

Good luck

I will, the guy I bought it from actually used most of the parts from the carbs off of the F bike to put together the original set. I asked him why he didn't just use the better set and he said he just couldnt figure out what they were off of, just the same as me, except I posted on the forums. And luckily I have the original airbox so I don't have to worry about that.
Well thanks again, I just got off work so I'll try opening up my air box a little to see if it helps, at this point its just playing around until I get the jets in the mail.

I got the jets in and was able to clean out the F bike carbs. I pulled out the pilot screws too and replaced the o-rings down in there. Made sure all the passages were clear with air and brake cleaner. 
Theres just one problem, it will not run. I can fire it on ether but it will not run off the carbs, at any throttle position. It just seems like its not drawing any fuel at all. Any input is appreciated.

Do not open the throttle when starting. The carbs are designed to start with it closed.

Did you set the fuel tap on PRI for a minute or two before trying to start? That is how you refill the carbs after they have been drained. 
Have you used the clear tube method to check the fuel level? This will tell you if fuel is getting to the carbs and it will show the fuel level in each of them. The fuel level is critical as it affects the mixture.
 

Is the airbox installed and the choke flaps working properly?

The airbox is installed and choke flaps do work. 
I did think about it later and realized the that the throttle valves wouldn't be open and no more fuel would get through if i touched the throttle while cranking. 
But even without touching the throttle, it will not even kick over.
I haven't checked it yet but, whenever it stops pouring rain outside I will go and check the float position and maybe try to keep it in PRI for a while longer. I had it there for around 15 seconds and fuel came out of each of the drain plugs but I'll trying leaving it there longer too.
Thanks for the suggestions so far.

Well I've messed around for quite a while with this thing and I just cant seem to get it to at least idle like it did with the original set on there. I'm really just stumped, I swear I've checked every passage, made sure every jet is correct and I'm not missing any parts. I've been playing with the float position but I'm not too sure where exactly its supposed to be set at. 
I've gotten it to sort of idle but but only with the choke closed, so I can't really tell why it wont get enough fuel. The other confusing thing is that the plugs look very rich, some even being wet.

So it can roughly idle only with the choke on, not rev up, and the plugs are wet. 

I dont believe anything other than the carburetors is the problem because it ran ok'ish on the other set.

*UPDATE* I had fouled plugs so it was only running on two cylinders, hence the wet plugs. It still seems like its not getting enough fuel, I am suspecting float bowl position but I keep getting inconsistent results with the clear tube method. They seem like they might be too low but I can't tell for sure.