03 Savage with a pretty good amount of white smoke consistently coming out near the muffler to exhaust pipe connection.  I can't pinpoint exactly where it's coming from, but that spot would be my guess. I've taken it apart and clamped that connection down as hard as I can and the bike doesn't seem to be backfiring, so I don't think there is an exhaust leak? It wouldn't blow white smoke even if there was one, correct? I can't see any oil leaking anywhere near the spot either.  It also doesn't seem to matter if I'm accelerating or the bike is idling, same amount of smoke.

It couldn't be coming from the cam cover? Or from the little window where you see the oil?

Idk if this any of this matters, but I have put some seaform in the tank recently, and my muffler does have a decent amount of rust in it.  When it's off and I whack it, the rust specks come out like a waterfall. I just cleaned the carb and the bike still only wants to run on PRI.  It dies after about 5 min. when it's set to ON.

Any suggestions???

white smoke can be oil or gas.
oil tends to be blue but in great quantities looks white.

check the vac line for gas, if you're running on prime, it could be a bad vac line or a bad petcock.
take it off and plug it.

Search "Seafoam" on Youtube and you'll see white smoke all over the place...
Check your petcock for the other issue.

Is the white smoke only coming out at the joint between the muffler and heap pipe, or is it also coming out the back of the muffler?  If the smoke is only coming out at the joint, then it sounds as if something is leaking on the hot pipe.  If the smoke was the result of some sort of issue with combustion, and you had a leak at the joint, then you would expect the smoke to exit at the leak and also from the back of the muffler where exhaust gas is normally supposed to exit.