So, I had some time yesterday, and here is what I did: Sprayed the WD 40, didn't notice anything on either side. But, I did notice that the vacuum line was starting to crack and was really hardened, so I replaced that and crudely synced the carbs with a dial vacuum gauge I borrowed from work. It was running better, but still net really great, and dying at idle after it got warm. Then I remembered that I had taken the petcock apart last fall when it first started giving me trouble and thought maybe I didn't get it back together right. So I pulled off the gas tank and petcock, took it apart and checked how everything was supposed to be from an assembly drawing in the manual. Everything was in place. To double check that the vacuum valve was working, after I put it back on the tank I set the petcock to "ON" and sucked on the vacuum line and no fuel came out, but when I set it to "RES" and sucked on the vacuum line fuel came out just fine. That may have been cause there isn't much gas in the tank.
Then just to see what would happen, I put it back together to take a short ride and see if anything had really changed. But when I got going, huge clouds of billowing white smoke came out of both tailpipes. I figured if I was in a tank it would have been enough smoke to make a daring escape.
So: the smoke probably means I'm burning oil. This might be because there is too much oil in the engine, but I'm due for an oil change anyway so I can drain some and see if that changes things, or look for gaskets or shavings in the oil itself. If letting oil out so it isn't overfull doesn't change things, or if I find gasket material or metal shavings in my oil, what do I do next? Is there an additive I can use to seal the leak into my cylinders, would it be the piston rings, burned valves, or something else in there going bad? Would burning lots of oil explain it not idling after it warms up but still acting lean?
Thanks in advance!