First thought is: you're running low on fuel.  If I were a smart aleck, that is what I would suggest you check first.  But I'm not.  My bike was running rough in the "on" position, but better on "res."  Also, gas was leaking from the carb in "on" but not on "res."  On "Pri" it ran great.  I bought a new petcock and now it runs like a champ.  I tore the old petcock apart to attempt the "on, off, res" mod that you can read about on this site.  It is still sitting in pieces in front of my keyboard, because I got sidetracked with other cool stuff I can do to the bike.

Anyway, I couldn't find anything obviously wrong with the petcock, but replacing it certainly fixed what ailed the bike.  The acid test for me was: If I switch it to "Pri" and all the problems go away, then it's time to replace the gadgetry that is between the tank and the carb.  Pri bypasses that gadgetry, so I figured something must be wrong with it.

There are several very informative threads on the site that explain clearly how the vacuum hose influences the operation of the petcock, and the weaknesses of the system.  

Thanks for the responses. I think I'll check the lines and then replace the petcock. I had the fuel spilling out of the carbs also. I thought that was just me. I guess not. I'm surprise to hear that it might be related to the petcock. I don't suppose the poor idle is related as well. At idle, the bike sometimes feel like its going to die.

Fuel spilling out of the carb?  definitely check your float level, float valve and screen.

But this happened on my original carb and then my replaced carb. What are the chances of 2 carbs being off? I thought it was from me flooding the carb through repeated cranking during the hard starts in the cold mornings.

Pardon my ignorance, but where is the float valve and screen?