I just purchased a 2007 400ex. Have only ridden it for about 5 hours. Noticed some popping and grinding in the rear axle housing in the swingarm. I have looked on line and there are many to choose from. Who is the best for the money. Also is this something that I should try, or let a pro do it. If i can do it.....can someone give me the specifics on how? PLEASE HELP IM IN A BIND HERE!!!!