I Can't speak for all years of 250, but, the 99-02 is quite easy to do. My avatra is a 05 250f chassis, its a pain in the a$$. The 250 conversion will require the swingarm to be narrowed about 8mm on each side, the swingarm motor mount to be drilled to 17mm, the head stay cut off the back of the motor and a new one fabricated on the front of the head, the 250 fron motor mount will be removed and repositioned, the bottom mount will fit, The pipe has to be modified, some guys are using a CR500 pipe and denting it around the water manifold and kick starter. The air box works as is, either use a short ceramic plug or warm the gas tank a bit and push up the bottom to gain clearance for the plug. This makes an awesome bike that handles night and day better than the stocker, the 250 has better suspension than the k5 and is much narrower.