Starting Issues- kz650

I just recently purchased a 1978 kz650 that hadnt been run in 4 years, and I couldnt get it to start.
So i just completly took my carbs apart and cleaned the bowls and jets, they were really gunked up. Im positive I put everything back together corrrectly, and now my bike starts, but it only runs for about 5 minutes tops, then bogs down and dies. It even gets to the point where it idles up, but when you try and take the choke off it dies. Could this be a vacuum problem? ive got the carbs good and pushed into the manifold. my fuel filters/screens are also good and clean. Im not sure whats going on! help!
-Alex

What shape is the inside of the tank like? Condition of the petcock strainer? I'm wondering if there's a bunch of crap slowing your fuel delivery. That might explain the 5 minute run time. If your carbs looked like damit' imagine what your tank inside might look like.

I am running into the same issue. I am leaning toward the petcock right now.
I plan on working on it tonight I will let you know if I have success.
L

Just to be sure it's not the tank cap vent, next time you run it crack the fuel tank cap open a little. Ed

Your carbs are still clogged up. The jets you cleaned screw into the carb body but the passegway behind the jets are still clogged.

yep checked my petcock screen, it was good, my tank is good and clean, i just completly restored the inside of it. Yep I'm thinking i need to clean the carbs again, although i was really REALLY thorough the first time around. If the second cleaning doesnt do it, could it be possible that they need synced?

Check to ensure your fuel line isn't bent at a sharp angle; that can impede fuel flow and cause the symptoms you describe. Ed

If not already done, would assure that each of the two bowl vent nipples is exiting to open air.

Without proper venting, gasoline won't enter the bowl. And the engine will die from fuel starvation when the gasoline already existing inside the bowl is used up.

Good Fortune!

culprit was a clogged in-line fuel filer (durr)bike runs AMAZINGLY now. Having a blast thanks guys!

Ok so now after a few days of riding, it has started to sound a little sickly, not as healthy and eager sounding as it was. I took off a couple of plugs, and they were soot black (running rich) any tips on how to adjust this? I already cleaned my air filters. ill also include a picture of my carbs. the mixture screw is the one closest to the air filter and with two notches marked around the edge right?

I may be wrong, but I'd say you have a carb jetting task in your future. Those carbs are not KZ650 carbs (VM24). They are larger than what would have come stock on any KZ650. Combine that with the fact that they are using pods and it becomes clear that they must be rejetted from whatever their original engine required if they are to have a fighting chance of working on a KZ650. That may have already been done by the previous owner, but if your plugs are sooting up so badly that the engine runs poorly it is quite possible that either the rejetting didn't hit the mark or wasn't done at all. Ed