It will work ok with the HD springs. However.... It will take little to no weight to work with those springs and it will lock up faster and way harsher and almost cause a bog situation till you dial it in. If you spend the money on the lock up, get some lighter springs. The lock ups do two things. Keep the power to the ground by eliminating wheel and clutch slip(except when wanted), and make riding easier with lighter springs. I get flamed for it, but I reccomend a lock up on any bike. They aren't just for big motors. You can put them on trail motors and ride effortlessly. Mine is almost comparable to the 450's