I have a 1981 CM400T. I re did the brakes in 2013 and replaced the fluids and the pads and cleaned and inspected the caliper. Since then I have put 6000 miles on the bike. Just wondering what the maintenance schedule for changing the fluid is. Is it based on time or miles driven? I was going to pull the caliper off to check the pads this winter so now would be a good time to change the fluid.