Noel is correct on time for all 6 outer and inner bearings.
To do the one center bearing(suggesting inner as well) will probably take the better part of 2 hours. Need to disconnect the 3 chains running to the center axle, if your machine has bolt on sprockets remove the bolt, the inner bearing has an eccentric collar with a set screw that will need to be loosened by loosening set screw and using a punch rotate the eccentric collar loose, the same needs to happen on the outer bearing collar, though if you wish ,removing the 3 bolts in the bearing flanges will allow you to pull the axle and do that on the bench.
There may be a video in the manual section of the home page.
