hello, and welcome to the board. there is a ton of information on these machines to be found by looking around here. the stickys at the top of this page, HL Chauvin from the main page, http://www.atis.net/
but to your specific question. the two halves of the governor split like an egg. it is interference fit together, and simply needs to be tapped apart. the required bushings and bearings are available from Case IH.
if you have a little time, Lurker Carl has the photos from the governor rebuild workshop at Cubfest to post on Rudi's site (cleancomputes.com), along with a detailed writeup on the topic. but the basics of good bearings, bushings, clean, freely moving parts, and pay particular attention to the cross shaft and carb rod connection play. as much of the 'slop' as possible needs to be removed for good gov function.