It is often said that you should not store your bike hot. For this reason many recommend you take it easy as you approach your destination, letting the bike cool down before you switch it off and leave it. Motorcycle engines (or any engine for that matter) think it is seriously uncool to ride them hard then, just as they reach harmful temperatures, switch off the cooling systems and leave them to sit, searing hot...

My solution: full fan indication and control

But sometimes it is hard to control this, some days it can be baking hot, or traffic is bad as you approach your destination. For me, I live halfway up a very steep hill, so when I get home the bike has just had a low speed high-grunt workout getting up the hill. It would be nice if I could have that fan running before I got in the garage, ready to switch off. Also, what if you are driving along, and you can see a blockage ahead, its blistering hot, and you know that there is no way around the traffic jam? I live in a city where this is not uncommon, and I have always wished I could have that fan running before I had to sit in traffic for ten minutes and the engine has gotten quite hot... and it would also be nice to see just when the fan has come on, as this can give you an indication of engine temperature.

The fan assisted cooling on the Shadow ACE750 is a simple circuit. A thermostatic switch merely senses high radiator temperatures and switches the fan on. Having the fan on when it is not needed can never do harm, as the flow of liquid through the cooling system is controlled by a separate thermostat. Having the fan on when you are going at some speed would of course be of little benefit, as the flow of air past the radiator would already be such that the fan would not increase it greatly. But if you were stationary, or nearly so, then the fan would be of great benefit, ensuring the engine remains a reasonable temperature.

One very bright LED...

I have not only added this functionality to my Shadow, but I can say that I have felt that it has well been worth it. I can now easily switch the fan on when I wish to, allowing for much more "intelligent" engine cooling. I can also see very easily when the fan comes on automatically. I can never hear my fan unless I am stationary, and usually only then when I am in the garage. I was previously under the impression the fan rarely came on, unless I was in stop and go traffic. I can now say that is not true, and can identify when the engine gets hottest. The most prevalent scenario is coming off the freeway. Every time I go from high speed (especially two-up) riding, down to slow riding the fan will come on briefly. The engine gets hot pushing it on the freeway, and when you exit and slow right down for lights etc. the engine no longer has that high speed wind whipping through the radiator, but it does still have a lot of heat from the highway ride, hence the fan will come on briefly.

All you need to do to add all this functionality is to add a light across the two wires that go into the fan, such that any time the fan is on the light is on, and a switch that could ground the lower fan wire in order to switch the fan on manually. Below you can see a circuit diagram of what I did. The blue sections indicate the part of the circuit I added:

I used an incandescent lamp bezel on the box, but replaced the insides with a extremely bright LED (green). The LED is much much brighter (14,000 mCd) than a light bulb could ever be, uses less power, does not generate any heat, is immune to vibration, and will never need replacing. I used a waterproof hood on the switch, and a waterproof cable gland for the wiring. All the wiring was run through military grade heat-shrink tubing, most of which I did not shrink in order to help match in with the existing wiring. I purchased all these components, along with medium duty automotive wiring and a cast aluminium box (which was waterproof) , from a local electronics store. It came to a grand total of about $30.oo Australian (around $18.oo US).

Under the switch box housing there is a hole (originally used for the choke cable as I understand it) which is a perfect location for mounting additional controls. I purchased a cast aluminium box from a local electronics store with this location in mind. The box I picked up was the exact width of the left handle bar switch box housing, and it was sufficiently deep to reach back far enough to allow a bolt to secure the box to the vacant bolt hole. There is a second hole a short distance in front of this bolt hole, and this was used to stop the box from rotating. I simply screwed a small screw out from the inside of the box that locks the position of the box. The screw does not actually screw into the switch box housing, but simply extends from the box into the small hole in the switch box housing. You can see these two points in the photo below:

Bolt hole A is what the box is bolted to, while the screw extends from the box into hole B, preventing the box from rotating.

@ Sean Flanagan, 2004. All rights reserved.