$140 and there yours.
http://www.ebay.com/itm/Front-Hub-Wheel-Bearings-Conversion-Kit-YFZ450-2004-08-/250850735376?pt=Motors_ATV_Parts_Accessories&vxp=mtr&hash=item3a67de7510#ht_3991wt_1185
not sure if that link will work but check it out, it might work for these hubs and its alot cheaper.just an idea