Harley-Davidson equipped touring models with adjustable rear-air shocks and adjustable front-air forks standard from the factory. Control the suspension firmness by adjusting the air pressure in the system. Minute changes in air pressure have a dramatic impact on the ride. Leaks in the oil seals, Schrader valve or the connecting tubing cause the system to lose air constantly and result in a soft, and dangerous, ride.
Inspecting the Oil Seals
Inspect the upper portion of the front forks and the shocks for signs of excessive oil leakage, which can indicate worn oil seals. Leaking oil may be visible on the components, or they may appear dusty due to dust becoming trapped in the leaked oil. Replace the rear shocks and rebuild or replace the front forks, if necessary, and ensure that the proper amount of fork oil is added to the front forks. Oil loss can lead to diminished rebound dampening and can cause loss of control due to the reduced contact patch integrity caused by the tires bouncing on rough pavement.
Inspecting the Valves
Remove the caps from the Schrader valves for the front and rear suspension. Attach a no-loss air pump to the valve and inflate the system to the appropriate pressure for the current bike load as stated by the manufacturer in the owners manual or shop manual. Do not use compressed air or a conventional pressure gauge to check the pressure. Compressor line pressure is sufficient to damage the air lines and fittings in the system, and conventional pressure gauges are too inaccurate to be relied upon for this procedure. Remove the pump from the valve and wipe a soapy water solution over the valve. The soapy water creates bubbles where there are leaks. Watch the valve for bubbles that will indicate a leaky Schrader valve. Repair the valve by removing the old valve core and installing a new one with a valve core tool.
Bleed Down Test
Ensure that the air pressure is at the appropriate level. Allow the bike to sit for a few hours and test again. Low air pressure indicates a leak in the air tubing going from each shock or fork tube to the Schrader valve. Inspect the tubing for kinks, cracks or leaks. Check each fitting with soapy water to eliminate them as a leak source. Replace any tubing or fittings that are found to be bad.