List of Bearings and Seals?

Hello all. Does anyone know of a web site or of literature that would give me the actual manufacturer's part number of the bearings and seals in a 89 yz 250? All I can find is yamaha part numbers. If I can find out the actual numbers, I can order these parts from work @ a much better price. Appreciate any info.

Roto, thanks again for response. I do know that they are on there, but I have a few seals that are unreadable due to age/heat. Also, there are two of the smaller bearings with nothing on them. Basically, I was just wanting to save some time by ordering them all at once and have them on there way versus taking one at a time out getting numbers off of them and so forth.... yes I know, lazy it is.