Brake Fluid: If I had to pick the most overlooked aspect of brake maintenance, it'd be regular brake-fluid changes. Most motorcycles use DOT 4 brake fluid, which is a polyglycol-based substance with a fairly high boiling point when dry. Unfortunately, DOT 4 is hygroscopic, meaning it'll absorb water directly from the atmosphere. As the water becomes entrained with the brake fluid, it lowers the fluid's boiling point, and since the water is heavier than the brake fluid, it sinks to the lowest point in the brake system, namely the caliper. Calipers can get mighty hot in use. In fact, they can get so hot they'll cause any water in there to boil, releasing vapor bubbles into the brake fluid, which isn't a good thing. Vapor, like air, is infinitely compressible, meaning it won't transmit any braking force. When you've got vapor in your brake fluid, you can squeeze the lever until you're purple and you still won't have any brakes. This unpleasant phenomenon is known as brake fade, and trust me on this, it's an experience we can all do without. Fortunately, when things cool off, the system should return to normal, which will be of little comfort if the brakes are now attached to a wadded-up motorcycle.