[stomp]

checking your plugs would be a good idea, but it's most likely the result of engine mapping.

What the charcoal cannister does:

The little vacuum lines on the bottom of the throttle bodies pull the fuel vapor from the tank vent hose through the charcoal cannister, thereby cleaning out the nasty fuel vapors before it vents to the atmosphere. Pretty simple, but has absolutely nothing to do with how well (or not) the bike runs.