Well after months of working to get my 86 XR600 ready to ride, I found that my front disc brake doesn't work. I installed a Baja Designs lighting kit to replace the lousy lighting the previous owner tried to make work and had the carboraters rebuilt so I wouldn't have any problems later down the road. My front brake was sticking so I replaced the caliper and I haven't been been able to get the brake to work. I'm thinking the master cylinder needs rebuilding because I can't get it to build pressure. I did have it empty for a couple of months so I'm sure the seals are bad now. Any thoughts?