Check your brake rotors for three thinks. First, make sure they are above the minimum thickness (this measurement is often encraved on the disc or given in your owner's manual). A badly worn disc wll often have a lip on the outer edge, making caliper removal difficult. Second, check that the disc isn't warped. With the motorcycle on a stand, kneel in front and slowly rotate the wheel: the disc should not move from side to side. If it does, it will push the brake pads away from the disc, requiring the lever to be pulled in further before braking starts. Third, check the brake rotors for cracks and heat-spotted or scored disc surfaces. Scores and heat spots will reduce friction and poor braking performance will result.
Replace brake rotors displaying any of the above issues and then fit new brake pads (new rotors come with a wax covering to stop rust, so make sure you clean the new brake disc thoroughly with brake cleaner before fitting).
The Brake CalipersRemove the calipers and inspect for leaks. Lever the pistons back into the calip; they should move smoothly and freely. Stiff or seized pistons will reduce braking performance and a caliper overhaul is required to rectify this. Check the caliper slides freely on its slide pins, and check the rubber covers are not perished. Pull back and grease inside.
The Brake LinesCheck all brake lines for damage, ensure all the routing clips are in place and the lines don't rub on anything through the full movement of the suspension.
The Disc PadsCheck the brake pad friction material; replace any brake pads showing 1mm or less. It is advised to use 'sintered' brake pads for Thailand, as wet and tropical conditions are not good for organic brake pads. Ensure wear is even between pads on the same caliper. Uneven wear could be due to a seized caliper piston or seized caliper slides.
The Brake FluidEnsure brake fluid level is above the minimum (most master cylinders have a sight glass). Replace brake fluid every two years, regardless of use. Completely drain and then flush fresh fluid through the entire brake system. Finish off with a bleed and ensure you remove all air fro the brake system. A spongy feel at the lever usually means you still have air in the brake system. Always use the specified brake fluid. If the manufacturer specifies DOT 4 use only that.
The LeversCheck lever adjustment. Ensure they are at the correct heights and not adjusted so much that the brakes start to drag. Replace any bent or broken levers.
Never leave brake fluid in open containers. Brake fluid is hygroscopic and will therefore absorb moisture from the atmosphere, drastically reducing its effectiveness and causing corrosion within the brake system Tag: Brakes Brake-Levers Brake-Fluid Brake-Lines Hygroscopic DOT-4 Brake-Maintenance