One of the problems with using compressed air however is moisture. Water vapor is present in the air when it is sucked into the air compressor - and the more hot and humid the environment, the more moisture is sucked into the system. The higher the temperature of the air, the more moisture it can hold. When the compressor compresses the air, the air is heated up, which means it can hold even more moisture. When this air is pumped into the suspension, it cools off, and the moisture condenses out of it - leaving water inside the suspension. This can cause corrosion.
The way Honda mitigated this problem is by putting an air dryer in between the compressor and the suspension. This air dryer is filled with a dessicant, which adsorbs the moisture from the air. The dessicant is a silica gel - the same sort of thing you see in little packets inside new product packaging. However, at some point it will become saturated, and incapable of adsorbing any more moisture. At this point, it has to be restored. This is something that should be done every year or two, depending on how often the motorcycle is ridden (and how often the suspension level is adjusted).
1. Open the false tank compartment and manipulate the compressor/dryer assembly to allow access to the hoses. Remove the banjo bolt fastening the hose on the left side of the control panel (1983 model is different). Be careful not to lose the O-ring between the banjo bolt and the control panel.
2. Remove the banjo bolt fastening the hose to the left side of the dryer. Again, be careful not to lose the O-ring between the banjo bolt and the dryer.
3. Disconnect the wire harness for the compressor.
4. Remove the compressor/dryer assembly from the motorcycle.
5. Unfasten the rubber tabs holding the top cover to the bottom cover surrounding the compressor and dryer. Pull the top rubber cover back to expose the compressor (on the left of the picture) and the dryer (on the right of the picture).
6. Lift the dryer and identify the cap. Remove the three screws fastening the cap in place. Be careful as you do this - there is a spring inside that will lift the cap as you remove the screws, so hold the cap in place until all three screws are removed.
7. Remove the dryer cap, and the spring, and set them aside.
8. Remove the retainer plate and set it aside.
9. Remove the packing and set it aside.
10. Once the packing is removed, you will be looking at the dessicant beads inside the dryer.
11. Line an oven pan with clean aluminum foil, and pour all of the dessicant beads onto the foil. Ensure all of the beads come out of the dryer.
12. Spread out the dessicant beads evenly on the foil.
13. Bake the beads in the oven at 350 degrees. When the beads are saturated with moisture, they will appear pink and red.
14. After approximately five minutes, the beads will turn blue. This indicates that the moisture has been removed from the beads.
15. Remove the beads from the oven and allow them to cool off for a minute or two.
16. Lift the sides of the foil to gather the beads.
17. Use a clean spoon or funnel to pour the beads back into the dryer.
18. Replace the packing and retainer plate in the dryer.
19. Replace the spring in the dryer, and carefully push the retainer plate down, compressing the beads.
20. Position the dryer end cap in place, compressing the spring, and replace the three screws.
21. Place the dryer back into the rubber housing, and refasten the rubber housing top in place.
22. Place the compressor/dryer assembly back into the false tank and reconnect the compressor wiring connector.
23. Reinstall the banjo bolt on the dryer fitting, making sure the O-ring is place. The O-ring should be lubricated slightly with oil, and the shaft of the banjo bolt should fit between the tabs on the dryer, to prevent it from rotating.
24. Reinstall the banjo bolt on the control panel, making sure the O-ring is in place. The O-ring should be lubricated slightly with oil.
25. Close the false tank, switch the ignition on, and repressurize the front and rear suspension to the correct pressures.
