I just got done with my first one. I havent read the link yet about the exhaust port but The sleeve and the crank case did not match up well at all so I took alot out of the case to match the port on the sleeve. I bored out a smoother more tapered outlet on the crank, also smoothed out the inlet on the crank. I really shreaded the intake ports, didnt do very well on these but hopefully I didnt mess it up to bad. Im sending it out to a freind that does this professionally so he can polish everything out and hopefully fix anything I did wrong. I didnt have the correct bits, I know I HAVE to get a good set if I ever want to do this again lol. Aside from a couple mistakes I can say Im not worried about doing it again, just not on a nice novarossi or something.