Hi Mors welcome to YOC the best place to start is new members sec, just a quick hi where you’re from in the world, bike experience etc. You’ll get a much better response as it helps other members help you. It is a tricky one as the frame is unusual on your bike but I have seen them with the pre division xj600 tank on. it’s not a straight swop though and obviously you’re gonna loose your side panels. Have a look on xs400.com, plenty on there with mods.