1987 yz 250, parts help?

I have a 1987 yz 250, but the bottom end is shot. I am looking at purchasing a shifting, functioning bottom end off ebay. the crankase and piston and crank parts numbers are the same, but I'm not sure that the cyllender will fit.

is there anyone out ther that can help me out? before I buy anything, I would like to know that it'll all fit.

thanks!

-Alex

ok . I can get an entire bottom end of ebay that functions, for about $100