dies at idle after running fine

[Triesandluth]

Still dying.  Had things to do,  hopped on,  warmed it up,  drove to the corner,  idling at the red light it died.  After minutes of trying to get it to stay running for more than two seconds at a time,   it finally started and let me rev it up.  Got it back home,  seemed fine.  Traded to my other scooter but the damned throttle cable froze from all my rain driving yesterday and being freezing temperatures.  Tried the s9 again,  made it to a different stop light,  died.  Took over twenty minutes to get it to start.  The way I got it started was by draining some fuel from the bottom of the carb, and pulled the fuel line and let the filter drain some.

 I dunno at this point. I've completely cleaned the carb and jets,  air filter is good.  When I pull the vacuum line from the intake that regulates the fuel flow, the idle goes up.  Getting too much fuel? Maybe my float is too high? I don't want to blame it on my low compression.  I'd hate to spend more and it still not work.
I'm no genius,  far from it, but I've made some junk run awesome from the grave (see my taotao). This is a fine machine that I can't get going.  Makes me sad.

[chaz35]

I get mine to start easy by choking the airbox with my fingers.  1st you have to disconnect the hose coming from the left plastic body panel to expose the small round opening at the top of the airbox.  Then, just use your 2 fingers to cover it.  My engine will start up, then rev up and die.  After I choke 1 or 2 times it will settle down and idle nice.  Without choking it, will take forever to start.

If dying at a stop after you have it running you have some other issue.  Don't know, but I think vacuum petcock could be your problem.  Try disconnecting fuel line and turning over engine with ignition off to see if a fair amount of fuel is coming out the carb (open the carb drain and put a can under the drain outlet to catch fuel).  Maybe fuel filter is clogged.  Good luck.

[zombie]

Couple things... When you pull the vacuum line you add air to the mix. The idle will go up or the bike will die out.  Revving up is normal.

Low Compression? 120 is the minimum the bike will start on. As the cylinder heats it expands, and the compression goes lower. Perhaps too low to run till it cools.

CDI/Stators also sometimes fail when they warm up, and will not work again until they cool off.

Draining fuel may be a coincidence in starting the bike or it may be you have some water in the fuel.

Start off by draining your fuel, and re-fill w/ 2 ounces of sea foam in the tank. Install a NEW fuel filter, spark plug, and verify the petcock is working as per Chaz. Pull out your auto choke, and make sure it moves at least 4mm.
Adjust your idle mix, and speed settings.

Once you know the fuel system is 100%, do another compression test. if it is 120 or below... Scrap the cylinder kit, and get a new one.

Once the fuel, and compression are 100% try the bike again. If it fails IMMEDIATELY test for spark. If there is no spark followed by spark after cooling off replace the cdi, and stator.