Welcome to the forums. Yes, I've changed those many times. If you look in the Fourtrax 300 repair manual, it will tell you that that bearing can't be removed and that you have to replace the whole case, but that's wrong. To get that keeper out, rotate that ring until the ends of it are visible in the small hole in the case. Now take a small screwdriver and bend one of the ends up through the hole. Now take a pair of needle nose pliers and grab the end of the keeper ring and pull it out. Don't worry about breaking anything, the wire will bend and pull right out.
Now, getting the bearing itself out can be a little hard. Make sure all the other bearings and seals are out of the case. Also make sure the filler cap is screwed out of the case. Put the case in an oven and heat it up to around 175 degrees F. Don't preheat the oven, put the case in the oven and let the temperature slowly come up to 175 degrees F. Wearing gloves, take the case out and take a punch and put through the small hole in the case, the same hole that you pulled the keeper ring from, and angle the punch so you can hit and and knock the bearing out. Be careful not to break the case. Sometimes it can be hard to get the bearing out, but heating it usually makes it come right out. I have tried without heating and haven't had any luck.
If you can't get the bearing out by heating it, Honda makes a special tool to remove it, even though the manual says it can't be taken out. LOL. I've never had to use the tool, though.
