engine help "dims to be exact"

[Milkman]

allright im rebuilding a 250r 83' and im just trying to figure out waht the dimensions are for the piston(??mm)..and the cylinder is rusted alot but it is in good shape no scrathces..im wondereing how i can get the rust out w/o boriing the cylinder out?

[trikerider2oo7]

if it isnt too bad you can hone (sp?) it

[Milkman]

what do you mean hone