Got my cooling fan installed today on my 400ex! I ordered this fan off Ebay, its a 220 CFM PC Server Fan (120mm or 4.75") and it moves some serious air!! Yes, I know it will not be water/dust proof like the Spal fan most people install, but I never ride in wet conditions down here in the desert, and even if the sand/dust damages the fan, it only cost me $5 with free shipping on Ebay! This fan was only a fraction of the price of a Spal fan, and this fan moves more air (the Spal fan is only 147 CFM).

I have not get a chance to really test out this fans cooling ability yet, but as soon as the temperatures warm up a little bit around here I will take it out and run some very thorough tests. I have a digital thermometer probe to measure the oil temperature in the tank when the time comes for testing.

 

Cool, spay the fan with electrical ignition spray. I spray all my elecrical with it. It leaves a invisable coating that repells water and seals conections. 3-in-1 Silicone Spray | Canadian Tire

Cant hurt.

 

Well I still haven't got a chance to thoroughly test exactly how much of a difference this fan makes in oil temperatures. But, I did ride it around my yard the other day to do a small test. I only have about 3/4 of an acre to ride on in my yard, so its fairly slow but aggressive riding mostly in 1st gear and just a little bit of 2nd gear. The ambient temperature was about 67 degrees F. After the engine was warmed up I went for a ride around the yard for about 15-20 minutes with the fan on and my oil temperature never got above 150 degrees F.