I had seen other people add Oil Coolers to XR650's and thought it would be a good idea to add one to my ATK as they run hot when run long distance. I used a Cooler off of a XR400 that wraps around the steering head.I also was switching to hard lines as well so you can see the Earls Alloy fittings that I welded to the cooler. If you are not going to do this you will need the oill lines off of the XR400 as well. You will need to weld a tab in the center of the steering head and a nut on each side that the cooler will bolt to.You can see that I had The Damper pin mounted as well as the Triples to make sure there was clearance. You can also see the modified steering stop for the Ohlins lower clamp. If you are using rudder lines at this point you can bolt on the cooler and start making your new lines. you will need the cooler ends of the lines from the XR400 and have your line sweged on. The retun from the engine goes in the Smaller of the two (the one on the right) and the line to the tank goes to the one on larger (left side). I switched to hard line so all of my lines are the same size now. In the above pic you can see the modified fitting on my frame for the tank return, it had to be moved up and a inch or so forward. Here are pics of the finished install and lines.