I did it recently on my YSM8R and it wasn't to bad a job. I DO have a small machine shop so my ability to make tools is a bit higher than a lot of folks.
I made a puller from 2 pieces of steel
bar stock and a length of 3/4" threaded rod. The piece in the bottom of the sleave mated closely with the bottom edges of the cylinder and the top piece spanned the head
bolts. I tightened a nut on the rod at the top and the bottom block forced the sleave out.
Putting the sleave back in is a bit more work. Once everything is out of the block you must clean all the water
passages you can get at very well to be rid of all the built up crud.
Once clean and ready for insertion lube the orings with heavy grease, align the sleave as closely as you can and use a large rubber mallet to(gently?) bump the sleave into place. You MUST be sure the sleave is seated correctly to the correct depth
or the head
will never seal properly. Your manual should give you the specs.
I used a vacuum cleaner(wet/dry threw away hose afterwards) to get all the scaped off crud out of the block before putting the sleave in. Fair warning: Do not even think of reusing the clothes that you do this job in as they will transfer black diesel
to all your possesions for yards in all directions. A couple of tyvec suits would be a good investment.
Good luck, go slowly, follow the manual, and its not that bad of a job and certainly beats the heck out of the cost of a new motor