steps for 2011 bike:
intake cam sensor - 10mm socket required. unscrew bolt and pull the sensor out (turn and pull). i used a toothpick to pull the old o-ring off, wouldn't scratch up anything.
exhaust cam sensor - 10mm socket required. i prefer to reach in from the right side of the bike, easier. top 2 radiator bolts needs to be taken out, and radiator needs to be shifted forward to make space. unscrew sensor bolt and pull sensor out.
both sensors will most likely have quite a bit of dirt on the outside, especially the exhaust cam sensor since it's facing the front. clean up the area before removing the sensor, prevents dirt from going into the engine when reinstalling the sensor.
hope this helps.