I bought mine on ebay, its not a actual manual but a disc for your computer. Its nice when working on sleds to be able to print out what I need instead of a book. Pretty cheap if I remember right.
I bought one from here for my Yamaha RX1 and Indy 400, Th RX1 was the yamaha factory manual. I just downloaded the 400 last night and haven't had time to look at it so I don't know how it is. For only $9 you can't go wrong. I agree with volcano buster that the factory manuals are the best. http://www.recrepairinfo.com/