Cooling fans and amp draw on WR450F

I have a 2007 WR450F that I just bought brand new from the dealer. I was thinking of maybe putting a computer fan or two on it, one on each of the radiators and a temperature sensor to switch the fans on and off. The temperature here in NC has already reached 97 degrees F and my bike overheated the other day riding some slow trails. Yesterday I put Engine Ice in it but I haven't had it back out yet to test and see if that helps any. Anyway, the fan(s) I plan to use draw about .5 amp each. How much can I demand from the electrical system before it becomes a problem? Being that it is designed to run the headlight from the stator and the battery is only for powering the starter, should I have a problem with the battery discharging if I run the fans directly to the battery? If anyone has any experience with this or any constructive input I'm all ears.

Here is the fan I put on my WR450. Works great. I forget the exacr current draw but it isn't much. The stator keeps up with it easily and the battery does not die when I am using it. I did not do a automatic thermostat figuring that is just extra complexity that I don't really need. I am fine just hitting the switch on the bars when I need it. I use this bike in the Philippines where it is hot and humid all the time and I no longer have any overheating problems even on slow, technical trails. One fan was plenty, and there isn't room on the other radiator to mount one anyway.

I made the bracket myself, it was quick and dirty but works just fine. Will probably do a cleaner one in aluminum though.

The fan is a SPAL brand waterproof 12V fan. While better than nothing, I don't think a computer fan is going to move enough air to really give you enough benefit to justify the effort. And also not being watertight (and likely made as cheaply as possible in china) I would not expect a computer fan to last very long in this type of duty.

If you are interested in the fan I used I can get you the exact model number and the current draw specs. Just let me know.



I'd love to have the part number if you don't mind. After last weekend I proved that I need to do something.

Is it just me or is there only one mounting bolt on the bracket??

Is it just me or is there only one mounting bolt on the bracket??

No, there are three... in addition to the one you see in the picture, there is one on the frame mount bolt of the radiator (to the left of the fan, hard to see it), and the bottom one (the empty hole you can see in the picture) can't go in until the shroud goes on.

Ah, Ok. I figured there had to be more to it than the picture let on. I was wondering about the bottom one!

The fan is SPAL model VA32-A101-62A "PULL" type

Specs are HERE

I got mine for $30 on ebay about a year and a half ago, there is one on ebay right now for $36 with free shipping

ebay item # 200609660461

Appears to be the same seller I got mine from.

Yea it costs more than computer fans for sure but moves a TON more air and will outlast a computer fan by a large factor.

Definitely happy with mine.

Thanks! Just what I was looking for.


Thanks for the reply and the pictures. I was going to go with the computer fan because it was thin enough to fit in there behind the radiator without hitting anything. I do like your point though about it being water proof. Do you have a general idea of how heavy your fan is? I was thinking about mounting it with zip ties like the photos I found in this thread. I really like how cleans the install is without any type of fan shroud. I just have two concerns, will the zip ties melt and is the fan light weight enough not to bend the radiator fins. I think I might try that guys set up first because I already have everything I need on hand. I will post some pictures when I get it done. I would like the temp sensor but I think I will try a toggle switch first just to if the fan works well enough to cool the bike. If it does then maybe put in a temp control switch. I fhte computer fan don't work out then I'll scrap that idea and buy a better fan. Thanks for the replies everyone.

The zip ties won't melt but they'll get brittle and break faster because of the heat. I was going to use a mounting kit for trans coolers, they're built for that environment.

Unfortunately most anything that touches the fins will bend them. The idea is to keep it to a minimum. That mounting kit actually has soft spacers that will help keep the moving parts of the fan away from the fins.

Yea I thought about the "through the fin" method like the add-on trans coolers for cars but dismissed it as dangerous for the radiator. That method is probably OK for cars which drive on (mostly) smooth roads but on our bikes which are pounding through bumpy trails there will be shock loads generated by the fan. At best, it will only stretch, loosen or break the zip ties resulting in the fan bouncing around or at worse cause actual damage to the fins or radiator itself. I didn't want to risk it and making the bracket was so easy that I just went that route. I made a cardboard template and then cut it out of the top of a dead battery charger. Quick and dirty hack but it works and "proves the concept" My plan is to make a cleaner and lighter one out of aluminum.

As for weight I am guessing the fan is around half a pound, and the bracket somewhat less... maybe a quarter pound? Overall the whole setup doesn't add much weight considering the benefit.

I think the computer fan is better than nothing but it isn't moving much air. The SPAL puts out many times that airflow and not only quickly cools the bike down when needed it is able to keep up with the heat generated when the bike is not moving whether it is in traffic or jammed up on a difficult single track. In theory it could sit and idle until it runs out of gas and will not overheat. The fan uses 24watts at most so the stock stator can keep up with it and the battery does not discharge if the engine is running. The computer fan is cheap though and probably worth a try.

Oh the bracket is the far better way to go, in fact I'm considering that myself. I know me though so before long you'll be able to ask how the through the fin method holds up off road!!!

Well, I decided to go with the SPAL fan. Last night I started constructing a fan shroud for the mount. I used some 20 gauge aluminum recycled from an old sign. I think I will split some rubber tube with a knife to use as a cushion between the shroud and the radiator. I also wired up a switch, ran it up next to the power button and attached it with zip ties. On the aluminum frame WR the spacing between the tank and the radiators looks to be a little different than the steel frame bikes. So I ended up making the bracket for the left radiator instead of the right side like I have seen done. There is more room on the left side of my bike to fit the fan. The fan should arrive in the mail on Friday so I can finish up the project. If it works well and cools the bike properly I plan to buy a thermo switch to turn on and shut off the fan automatically. As soon as I figure out how, I will post some photos.

I got the Spal also, it should be here tomorrow so I'll have a busy day Saturday with my new exhaust arriving tomorrow too.

I'm probably going to wire it hot to start with to prove the concept then move up to the thermostat controlled relay. I may go with a switch but probably won't do a fancy mount since the ultimate plan is the automatic controller.

Ahh this is going to be a fun weekend.

The thermoswitch is a good idea, just didn't need the added complexity in my situation.

SPAL has a thermoswitch kit with a wiring harness that will mate with the plug on the fan. It seems a bit pricey at $45 but includes everything you need to do the automatic control....

Check ebay # 390231281599 or search for SPAL 185FH Harness Kit

Can you remember what switch you used for controlling the fan?



Can you remember what switch you used for controlling the fan?



I went yesterday to PepBoys and purchased a universal fan control $34. The kit is prewired with good instructions and was very easy to connect to the bike. It came with the relay and a thru-the-fin heat sensor which makes it easy. This way there is no worries about messing with the plumbing on the bike to insert a sensor that reads temps directly from the coolant fluid. All you do is insert the sensor between the radiator cooling fins to get the heat reading.

Anyway, I wired it all up last night and it works like a charm. It has a wire that goes to the ignition so you don't have to worry about forgetting to turn off an external switch. The relay itself is somewhat large but still works well. I originally thought to mount it under the seat near the battery with all the other electrical junk but it was too big. So I just ended up mounting the relay on the bracket where the AIS module used to be, the bolt holes even matched. The temp control also has an adjustment so you can kick the fan on anywhere from 170-210 degrees F. When I get home today I will post the exact model for the relay/sensor kit I bought and I'm also gonna figure out how to post pictures.

Here is a trial fit of the bracker I made.?action=view&current=shroudonrad.jpg

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now