A quick background: a little while ago, I bought some of those permanent brass adapters to put into my carb intake boots, which makes it much easier to do a carb sync. They are little brass plugs with holes in them, and a rubber cap.
This past Saturday, I went to start the bike, and noticed it was idling funny. Hmmm, I thought, that's strange, but chalked it up to the unseasonably cold weather, adjusted the idle screw a bit, and went on my way. I went for a 400mi ride, and the bike ran awesome, no issues, other than the strange idle, temps were normal, never hit the fan once. I did notice a backfire on decel/engine brake a few times, but thought I actually was running a bit rich if anything. The idle seemed lower than normal, and when revved, it took a bit longer to return to idle. I thought "lean" right away, but that didn't make sense, so didn't worry about it much.
The trip was awesome! Went through a couple of rainy patches, but overall, really good road conditions, lots of twisties, absolutely amazing scenery!
So today, I go in to have a quick look and see what could be wrong with the bike. I pull of the tank, and figure I'll start with the idle screws, and see if I could figure out the strange idle. That's when I noticed it: the rubber cap from the brass plug on cyl #2 had somehow "popped" off, and was sitting underneath the starter.
Right away, I knew what happened. That whole trip, #2 was running lean because effectively it had an intake leak from the uncovered plug on #2 carb boot. So this brings me here to ask this question: Is there any chance I could have done any damage since #2 was lean the whole time due to the intake leak? For like 400mi? I'm hoping I didn't burn out any rings, since I just put in all brand new rings not too long ago. I did notice my oil level went down a bit, so I'm just hoping it was normal loss, and not burnt rings or glazed cylinder? Would that be enough? The trip was mixed riding - cruising/full throttle bursts - so I'm really hoping I didn't do any damage. 
Let me know your thoughts so I can sleep tonite...
Needless to say, the stupid adapters are out, and the stock screws are back in so this doesn't happen again! I wouldn't recommend the permanent adapters to anyone. If I did do damage, you bet I'll be writing the company to get myself a new engine/bike. LOL2
