ok.. i've bought a 1983 YZ250K and at some point the brake side rear sidecover has been swapped over for a 1982 YZ250/490J version. now they're almost exactly the same except the middle mounting position is slightly forward on the J compared to the K due to a different angle on the frame tube, and the recessed mounting point hits on the K airbox. i'd thought about cutting the recessed mounting point off but as this is original plastic it's probably worth keeping original and swapping.
if anyone's interested please send a pm and we'll work something out
