I am tempted to retrofit a rear disk brake on my '87 XR600 to replace the marginal drum brake (and upgrade to a 18" wheel as well). It looks like a fairly simple swap - it appears that I can use my existing swingarm - will the brake caliper holder fit onto the existing drum brake hub stay on the swingarm? Will the brake pedal need to be replaced with a disk brake unit? I know I will need to fab and weld a couple of brackets to hold the master cylinder & reservoir. Are any additional/different wheel spacers required? On another subject: Does anyone know if a '88 & newer front disk brake rotor will bolt-up to the '87? Anyone have any extras of these items laying around that they want to get rid of? Thanks!