not sure, but take the top cap off of the fork leg.make sure that the front end is off the ground,so you dont pop the spring in your face.find some washers that fit over the spring and slide in the fork leg.make sure the washers are all the same size in hight.i tall depends on how old your springs are and your weight. good luck. ps
you can always add washers to make it stiffer,but dont to much for street use.i hit a tree root in a hard right corner.lets just say my cb550 can jump while turning