Fan reversal

A problem experienced by some owners of the GL1800 Goldwings is overheating at slow speeds. At speeds ~20 mph or less the fans are used. These fans suck the air through the radiators and out the front of the bike. This presumably is for rider comfort. At speeds in the range of 15-20 mph the incoming air clashes with the outgoing air from the fans resulting in poor air flow through the radiators. Prolonged use at this speed (slow traffic, parades, creeping along) can cause overheating. The 2006 and newer Goldwings have larger fans and radiators to lessen this problem although I think it occasionally still happens. There was also an ECM update on the older Gl1800s. A mod some people do is reverse the fans so the fan-generated airflow is always out through the sides of the fairings to match the incoming air. People have gotten good results with this setup. I had my bike taken apart for other reasons so I decided to do the mod. It couldn't hurt anything. Reversing the fans requires two steps: (1) reversing the fan blade assembly on the motor, and (2) reversing the wiring in the connector so the fan motor turns the opposite way. You can access the fan & radiators without removing this much but I had it all off anyway doing other things. I wanted to see how the bike is assembled and where everything goes. When you take this off the bike there's a lot less mystery about the bike. Here the fan & radiators were removed without taking off the front plastic. Here is the left side fan/radiator assembly off the bike. There are two bolts holding it on and one tab it sets in. I tested the setup to make sure it worked and that someone hadn't already reversed it. The fan puts out lots of air. The stock setup has ~1/8" to 1/16" clearance between the fan blade assembly and housing bottom. When the fan blade assembly is flipped it is now higher than the housing. If reassembled now it would hit the radiator. The fan housing needs shimmed away from the radiator. I used two 1/4" washers on each mounting tab to regain the needed clearance. Three washers were too tall. I ran the fan to make sure it would not touch at speed. The stock bolts are too short to be used with the new shims. I bought new M6 x 1.0 x 1" bolts from Lowes. Use blue locktite on all the bolts. The last thing to modify is the plug. Insert a small jeweler's screwdriver in the tab to release the wires and reinsert them reversed. Repeat for the other radiator/fan assembly. Reversing the fans is actually a pretty trivial project. It's getting to the fans that takes time. I reinstalled the radiators, filled the bike with coolant, and let it idle until the fans kicked on. The fans blew the heat 3-4 feet to the sides of the bike, and I had no leaks.