The '84 CR250 Husky is water cooled and I am assuming you want an air cooled top end . I will have a look through my stash and see if I have one surplus to my requirements . When you say that you have an '85 WR250 that you want to use in Evo , I take it that it is a twin shock , water cooled model ? You may run into trouble fitting the air cooled top end , because the liquid cooled cylinder has a centre exhaust port exit , where the air cooled cylinder has a side port exhaust exit and the frames are different to suit the different pipe configuration .