So I just got done rebuilding the carburetors. Bike seems to start up. However I noticed after the bike warms up the idle starts to climb. I set it at about 1400 RPM. But by the time the bike reach is operating temperature the idle is closer to 4500 or even 5000 RPM this is even after turning the choke off. The only way I have been able to lower the idle after the bike is warmed up is to turn the idle down on the carburetor. The problem is at that point the bike doesn’t want to start. My guess is that something is opening up as it warms up causing increased airflow Which of course raises the idle
Air leak between the carburetors and rubber joints to the cylinder head potentially - spraying with brake cleaner can aid in locating the source of the leak Otherwise that's an idle jet setting being too lean or it's a combination of several elements
Yeah check for air/vacuum leak's on the intake manifold's, as they age they'll develop small hairline crack's that can let air in. Did you sync the carby's after rebuilding them ?
What @ruckusman said, screw the pilot mixture screws out 1/2 a turn and see how that goes. If it improves then try tuning by ear http://litetek.co/Guide_FuelScrews.html