I have a 95 KX250 with 43mm diameter KYB forks. I am looking to increase the spring rate but I am finding that only .38kg/mm and .40kg/mm rated are available off the shelf. I need a spring rate of 0.50kg/mm. Has anyone ever tried this on these forks? I talked to a custom spring shop about fabricating a spring with this rate. They were going to hold the O.D of the spring the same and let the extra wire diameter be on the I.D. of the spring so the spring won't rub the outer fork tube. The problem with this idea is that the steel stamped spring guide will no longer fit. I am also concerned that the plastic cartridge will now rub in the spring I.D. If any body has experience with this upgrade, please chime in.