450 wild rear axle bearings

[dogsbody]

hi guys, ive got a 450 wild quad with shot rear axle bearings, is it worth attempting myself, or are there special tools involved, i dont want to get into it to find i cant complete it. does any one know how much it would cost to get done at a dealer [im in perth australia] also whats the best engine oil to use for this bike. any help would be greatly appreciated ,cheers.
ps how can you tell from the chassis number the year of manufacture