I just did this yesterday...
Get a jack stand and tip the wheeler on its side, making sure you turn off the fuel and that your oil breather is blocked. Take the bolts off the foot peg and move it out of the way, then loosen the kickstart. Remove the bolts on the crank case and slowly pull the case up, you'll most likely hear a 'ping', thats ok, its just the spring for your kick start. Remove all the old seal, clean, reset that spring before you put the cover back on and put all your bolts back on. Rebolt your foot peg and its as simple as that, done in 25 mins.