I only know stuff about the 93-97 bikes. Have you tried looking for interchange here?hi Mike, I did just speak with you about the motor interchangeability for the 92 model EXC I am trying to rebuild, versus the 250/300 motor you're working with. doubledoor, you may know as well, I sent some messages to you about this also. Do either of you , or anyone else, know what motors interchange with what years? Mine is a '92 model 250EXC. What transmission cases bolt into what all year frames ? If possible,I may be also looking for an upgrade to 300cc engine. The one I have prolly needs it all, crank,cylinder,etc. If I'm gonna spend money, and resurrect it, should I, could I just upgrade to a 300cc? Will it bolt in? Should I just part it out , and get a later model 2 stroke? I want a KTM 2 stroke dirt bike. I have one , that needs some megadolleros spent upon it. Advice ? what info u got for me , doubledoor ?