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When I was wrenching I found the over flow tubes sometime developed a crack. I soldered it and told the owner he would need a new bowl if it leaked again. He was happy to be on the road again and I never heard from him again. I guess that was a good thing.
Steve

Just to update, I bought a couple rebuild kits, and replaced the offending needle and seat. So far, no leaks. We will see in the morning.

Sooooo it did not work. I still have the same problem from the carb with the accelerator pump on it. It takes a couple hours, so it must be a very small leak. After a few hours, I check each over flow tube, and as soon as I put my finger over the hole and take it off, it pours out what looks like the amount that is in the over flow tube. Its really strange.
I took the bowl off and filled it with fuel and left if for a while, and it did not leak. so i dont think there is a crack in the tube or the bowl.

I'm going to try checking the float, make sure its not bad, then maybe switch around the needle assembly to try to narrow it down. URRRGGGGG!

Anybody whos got suggestions, shout 'em out! I'm pulling my hair out!

Thanks

#2 carb is connected to the petcock. If the diaphragm on the petcock vacuum side is worn or torn it will leak gas to the #2 carb, causing overflow and potentially fouling the #2 plug after around 100 miles. It took me a while to figure this out on my 79. I got the diaphragm from Z1 and I posted my repair here about 2 months ago.

Also before you get into it. Sometimes just turning the petcock around a dozen times helps seat the seals. See if that changes anything...

One way to test if the petcock is the problem is to bypass it.

Remove the gas tank and make a temp fuel source. I use a plastic ketchup bottle, cut off the bottle and using a 1/4 clear tube to connect to the fuel line that has a fuel filter.

I keep the air hose from the #2 carb in place. Use a 4" 1/4 clear tube on the end of it, bend it over and clamp it with a clothes pin to seal the line. Don't bend the actual air hose.

Run the bike and notice the overflow tubes.

Another way with the gas tank in place is to switch the vacuum line out of #2 to another carb. And use the other plug on #2. The 2 will be fine and the overflow will likely happen on the other carb if the petcock diaphragm is faulty. This is also a way to test if the fuel accelerator assembly under the #2 carb is faulty (it also has a diagram that can be replaced).

Are they new seats and gaskets? If not try a little grease on the gaskets. They might be leaking there. Grease is a good sealer for old gaskets if they're not damaged.

I had a similar problem on my 750. Sometime the overflow tube inside the bowl will develop super fine cracks in them just from moisture and temp changes over 35 years. Pull the bowls out and look at the over flow tubes. If you see anything that looks like a line running up and down them, that's more than likely your problem. Solder or some marine jb weld should do it.

Ok. So for anybody who might come across this in the future, I did get the carbs to stop leaking. Heres what I did.
Checked the bowls for leaks by taking the offending bowl off, filling it to the brim with gas and setting in level soft vice. Let it sit for hours, and checked it for leaks. No leaks.
Next, checked the floats. Took them out, and put them in the said gasoline filled bowl. They floated. I took the neighboring float out (careful not to mix them up) and checked it against my first float to make sure they float the same. Floats are good.
Next, check that floats are not bent: with the floats still attached to the carbs, i got down at eye level with the floats. With the floats hanging in the down position, you can kinda line them up with the main jet as a level line. One of mine was off a whole bunch, so i bent them level.
Put everything back together, still didnt stop the leak.
Next, I switched the floats with the neighbor carb. reassembled, still leaked. Switched the floats back to original place.
Next, I switched the needle assembly from the neighboring carb, reassembled, and the leak followed the needle!
So these are brand new needles mind you. I removed the bad needle assembly, and did what bounty said with the qtip, drill and some brass polish. Shined it up the seat real well, and touched on the needle as well.
Then I put just two wraps of t-tape around the threads, and re installed it. I made sure it was tightened accordingly with the washer, and reassembled everything.

The last thing i did was to reset the fuel levels in the carbs i messed with, just in case. its been a day and a half, and NO LEAKS! VICTORY IS MINE! MWAHAHAHAHAHHAHA!

Sorry. Yes. no leaks, So hopefully that helps somebody in the future, as this has taken me a couple weeks of head scratching to figure out. Thanks for everyone's help!