I'm not really sure what your problem is. It doesn't really sound like carbs to me, as gunked up carbs should be more consistently terrible to ride with. My wild guess is that there could some sort of issue with your shifter, causing you to get some false neutrals, but I'm really not sure. You could also double check that there's enough slack in the clutch cable, and that it's not binding on anything -- if it's occasionally sticking it might cause the issue you've described.
The only ways it would make sense as a carb issue is if you either had an intermittent vacuum leak, if there was some loose debris rattling around in your carbs which was occasionally obstructing the flow of gas, or if the floats were adjusted incorrectly (or not floating properly), keeping the float bowls from filling up with gas properly.
My prescription: ride the bike around the neighborhood a bit more and see how often it happens.
As to the idle: adjusting the idle is fine, but any time you make a change to the bike you'll want to keep track of what you do, and not change too many variables all at once. Also, I think fishdip was referring to
adjusting the idle mixture screws on the carbs, rather than the i
dle speed adjustment knob. I don't see where you said anything about adjusting the idle on the bike, so I'm not really sure what fishdip is talking about either...
