Fork seals play a vital role in the function of the front suspension on the Honda CX500. These retain the hydraulic fluid that aids in the dampening function of the forks as well as anti-dive and stability during braking. Besides the unsightly cosmetic damage that leaking fork seals do, they can contribute to poor performance of the front suspension. Leaking fork seals should be replaced promptly to maintain the safety and appearance of your motorcycle.
Remove the front wheel from the motorcycle. Remove the two bolts holding the brake caliper to the fork and remove it. Tie up the caliper with wire to avoid tension on the brake line. Remove the front fender.
Loosen the upper triple clamp bolt. Loosen but do not remove the top fork cap. Loosen the lower clamp bolt, and slide the fork out. Hold the fork tube in a vice with soft jaws. Do not overtighten the vice to prevent bending the tube.
Remove the upper fork plug from the fork tube. Slide the spring out. Remove the fork from the vice, and turn it upside-down, pouring out the fork oil. Pump the fork by hand several times to ensure that most of the oil has been removed.
Clamp the fork base in the vice, and remove the Allen bolt at the bottom. Pull the fork tube out of the bottom case. Remove the dust seal from the bottom of the fork tube, then remove the clip that holds in the fork seal. Carefully pry the seal out of the lower half of the fork assembly, careful not to cause any damage. Clean all parts with solvent.
Using a fork seal driver, install the new seal in the lower half of the fork leg, spring side down. Replace the clip and dust seal. Use a new dust seal if the old one is cracked or damaged. Install the upper fork tube and parts into the fork. Screw on, but do not tighten the upper fork cap. Screw the Allen screw back into the bottom of the fork using a new copper washer.
Remove the cap and pour in the recommended amount of fork oil. Screw the cap back on, using a new O-ring. Install the fork in the triple clamps, tightening the lower bolt to specification. Tighten the fork cap to the proper specification before tightening the upper bolt to the proper specs.
Install the fender, the brake caliper and the front wheel. Torque all bolts to specs found in the manual. Pump the suspension a few times to ensure there are no leaks. Pump the front brake lever a few times to reseat the brake pads. Take the bike for a test drive, and check for leaks.