Cooling the pig: Adding an oil cooler fan

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The GS has been the best bike i've had thus far. It's taken me through 23 states and 2 countries through the short 2.5 years (and 41,000 miles) we have been together. Although there are many modifications on the market for all sorts of issues or qualms, not much is on the market to help with cooling these pigs. The GS-P kits are available through BMW, not cheap or easy to find though. RT-P oil cooler fans and shrouds can be found, but are not plug and play. I've read of people using 12v fans from computers or electronics with success, but have not seen any write-ups or even pictures. This is the route i decided to go

After some measurements, i visited McMaster-Carr and found a nice little fan that i will be using for the project. Measuring 3.15"x3.15"x1.5", it's a touch large, but it is spec'd at pulling 130cfm of air.


The fan is not advertised as being waterproof or even water resistant. No idea how long it will last, but it is a starting point.

Picture showing how it will be mounted. As seen in the picture, the fan fits under the crossmember and extends down to the top of the light bar. Ignore the yellow wire, using that to help hold the fan up while i take a picture. Did a quick jumper wire just to see it run. Fan winds up a little slow and is pretty damned loud when running (71dB), but it moves quite a bit of air.



The goal of the project is to allow the bike to move at slower speeds off road and in traffic without worrying about the oil temp rising to 7+ bars (260F+). Although the police bikes use thermoswitchs to turn on the fan, i plan to use a simple on/off switch on the bars down by the triple tree.

[Beard]

let me know how it goes

[Dan Alexander]

[Yeahbaby]

Hey NONE, I have a RTP fan housing less the fan if your interested, gratis. Lets see what you can do with it. PM me with the address. I too have been working on this. I thought a 3' bilge blower might work. But I was looking for a higher cfm blower. I was also trying to come up with some way to blow air onto the front of the cylinders to cool them down as well, because I believe most of the cooling is done at the cylinders, not oil cooler.

[Twilight Error]

Originally Posted by Yeahbaby

Hey NONE, I have a RTP fan housing less the fan if your interested, gratis. Lets see what you can do with it. PM me with the address. I too have been working on this. I thought a 3' bilge blower might work. But I was looking for a higher cfm blower. I was also trying to come up with some way to blow air onto the front of the cylinders to cool them down as well, because I believe most of the cooling is done at the cylinders, not oil cooler.

There is a large oil passage in the head that runs around the combustion chamber's circumference. Oil picks up heat here and it gets pumped through the cooler. In that respect, its very similar to the way a liquid cooled engine is set up. My bike hasn't overheated (yet), so I'm not entirely sure what set of conditions would have to occur, but I strongly suspect low speeds and high ambient temps are on the list. Boosting airflow through cooler can only help keep oil temps down.

[Undermoose]

http://www.bmwmotorcycles.com/us/en/..._overview.html

[GP1200]

Why exactly do you need a fan ? These bikes were designed to run without them. Has there ever been reports of overheating and destroying the engine ? The GS is sold in desert states like Nevada and California and I'm pretty sure if there was a threat of overheating BMW would have put one in as standard. Ha ha ha just kidding , they can be pretty stupid sometimes. But I'd like to hear feedback of one person who suffered a failure from overheating.

[mwood7800]

My last trip to the blue angles air show I was stuck for an hour in stop and go here in fl. My temp gauge on my rt was topping out. I tried pushing but that got old. No where to ride the side of the road. Same thing happened at bike week in Daytona. My buddy fried his road king.

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so things just got a little more interesting...

Yeahbaby graciously donated an RT-P fan shroud to the cause. I'll be test fitting this later this week. looks like it will take some trimming to work, but if it can be made to fit, will allow a larger fan to be utilized.

[Gregg Wannabe]

Bump to keep thread alive. I am very interested in this modification. I overheated my 1200 GSA last weekend and need a fix.

[(none)]

Originally Posted by Gregg Wannabe

Bump to keep thread alive. I am very interested in this modification. I overheated my 1200 GSA last weekend and need a fix.

No worries. Haven't had much time to do anything with it yet. Hopefully this weekend. Got the switch in i'll be using this week.

[mwood7800]

Why not a fan off a k75. Always some on eBay. They put out great air.

[(none)]

Originally Posted by Yeahbaby

Hey NONE, I have a RTP fan housing less the fan if your interested, gratis. Lets see what you can do with it. PM me with the address. I too have been working on this. I thought a 3' bilge blower might work. But I was looking for a higher cfm blower. I was also trying to come up with some way to blow air onto the front of the cylinders to cool them down as well, because I believe most of the cooling is done at the cylinders, not oil cooler.

Sent you a PM. I was toying with using some ducting, i can see how well the housing works.

Originally Posted by mwood7800

Why not a fan off a k75. Always some on eBay. They put out great air.

Any idea how large they are? The ones on the K1200 i had seemed quite a bit bigger then needed for the short oil cooler.

[GS Addict]

If you are satisfied with the results take it to the next level and get the motronic to turn the fan off and on.
On 1150 RTPs a relay is sinked to ground thru pin 17 of the motronic ma 2.4.
The relay contacts can be used to automatically and optimally operate the fan.
If you need a contact pin to do this mod, PM me and I'll mail you one.

[WindSailor]

Originally Posted by GS Addict

If you are satisfied with the results take it to the next level and get the motronic to turn the fan off and on.
On 1150 RTPs a relay is sinked to ground thru pin 17 of the motronic ma 2.4.
The relay contacts can be used to automatically and optimally operate the fan.
If you need a contact pin to do this mod, PM me and I'll mail you one.

Interesting. What about the 1200?

Here is a picture of what I've got - SPAL fan - around 120cfm - lighted LED switch is by the speedo. This is bolted to the upper crash bar on a 1200GSA. The SPAL is waterproof etc. (got it on eBay ~$50) but I can only fit one in there. Since I've installed it I really haven't had to use it, so I can't say just how effective it is. I know it works though...