The piston's don't come out the bottom... To start with. Buy the manual, eventually you will need it. You can also do a serch on here for top end, and I'm sure there are about 5,000 threads on what is involved in a top end rebuild. But, to answer the origional question, as long as you get a manual, there is no reason why you can't do the wrench work yourself. You will have to pay someone to do the bore/hone on the cylinders though.