If your bike seems to have a rough idle (rpm "lopes" or fluctuates) and idle speed is low, then you might have clogged pilot jets (causes a lean condition). Many if not most Concours owners will adjust the idle speed knob to compensate for the drop in idle speed. That is a valuable clue if you just recently bought one like I did. If the idle adjustment knob had been adjusted to the max position, that's a red flag. It suggests there's a problem. The pilot jet is not only used for idle, but covers low speeds up to 3000-3500 rpm. Problems with the pilot jets mean poor low speed performance. Hard starting is another clue. Be careful, a vacuum leak might have the same symptoms. I recommend checking for vacuum leaks prior to carb removal. MOB has good info about looking for vacuum leaks.
Why do pilot jets clog up so easy? They are the smallest jets in the carb, so they are the first to get gummed up. Untreated gasoline (especially if it contains alcohol) will go stale after a few weeks and start causing problems. If your bike sat for a long time, there's a good chance you'll have some issues with gunk in the carbs from the bad gas. Where is the pilot jet? Under the bowl next to the main jet. I'd say carb removal is pretty much required. Technically, some people have removed the bowls from the carbs with them still on the bike, but you'd need small hands of a child and special tools. So, not impossible, but realistically, forget it. Carb removal is a bit intimidating, but if I can do it, anyone can.