Hey guys.. first post so go easy on me. I have just replaced the rear wheel bearings on my 01 xr400 and on tapping out one side it disintegrated, so as the boys are saying.. any play.. change em. Takes about an hr tops. Another tip.. if you are trying to save money, do not buy bearings from honda, otherwise they'll charge you the national debt of bolivia for two bloody bearings. I paid $15AUS for 4 bearings Cash money.