yeah its easy. one bolt and it'll slide out. the metals are machined with tight tolderances so its kinda difficult to stick it back in but once you do its easy...
if you have ever played a brass instrument...its like putting a tuning slide back on...kinda fights.
put some oil on the seal when you put it back in and also in the hole in the head so it slides in nicely.
since its one of those gears with angled teeth it will turn when you remove it and when its inserted, so you should make a note of this...as you pull it out feel for where the gears no longer mesh and THEN note another spot where you'll want to put the rotor when you insert it, or just do it a few times until you get it to line up once its all the way in....if that makes any sence.
basically you pull it out, cut/break the old rubber (now stiff plastic) seal and slide the new one on, and put a little oil on it andthe shaft i think.