I have been interested in reading about the different repairs/fixes from several members about various Computer Leveling Air Suspension System (CLASS) related problems, in particular, compressor failures. Having had only intermittent use of my CLASS system last year and complete failure this year, I decided it was time to go to work on the compressor. When the system would fail to operate, I would get different error messages on the controller; E 1, E 2, E 3, and E 4 in no particular order. This is on a 1983 Royale with 35,000 miles when the trouble first appeared. Removal and cleaning of compressor was simple and took in the hour and half time range. The factory service manual is more than adequate in the removal and replacement of the compressor; however it does not go into disassembly or give a break down of the compressor itself. The only caution I have here is to be sure and pay particular attention to how the two reed valves are placed under the head and above the compressor's piston. They could easily be installed backwards and in the wrong sequence. After reassembling the compressor, it was bench tested for operation and then reinstalled.
CLASS still would not operate. Back to the service manual to troubleshoot the CLASS system. The first item was to remove the controller from the right-hand side of fairing and check for battery input voltage which was present. Next item was to check for sensor output voltage, the valve output voltage for front forks, rear shock and decrease pressure valve. At first no output voltage was present but as I would move the controller to test the different value voltage, the voltage would come and go. My first thought was the electrical connector plug to the microcomputer in the controller was not making good contact. Further tests proved the connector contacts to be good. This left the microcomputer as the cause. I then recalled the article by Buck Parrot in the April 1992 issue of Venture Road about cold solder joints. I disenable the controller to get to the circuit boards of the microcomputer. A caution here; you can handle the circuit boards by the edges with no problem but be sure and don't touch any of the components on the circuit boards themselves. They are very sensitive to static electricity from your body and can cause damage to the components. They are not particularly fragile from rough handling but to the static electricity charge itself. Upon inspection with a magnifying glass, 4 cold solder joints were found on the under side of the electrical connector where the solder connection was made to the printed circuit board. Using a low wattage soldering iron, the cold solder joints were resoldered. The controller was reassembled and installed and the CLASS was returned to proper operation.
One final thought on the compressor; I'm not so sure if it wouldn't be a good idea when you or your dealer performs your regular maintenance on the dryer and the suction filter of the compressor to use a little WD-40 or Break Free in the suction filter pipe on the compressor to lubricate the inside of the compressor and thus eliminate the necessity of the complete disassembly of the compressor.
Dwight E. Dowds #00186
Yuba City. CA
? A good way of finding cold solder joints is to spray them with a freeze-type solution (available from electronics stores).