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Radiator Fan on 2 stroke?

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Has anyone put a cooling fan on a two stroke? I am on the search to make my CR 250 run cooleron slow tech trails... Would you need an aftermarket stator or what?

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I believe that almost every modern trials bike out there, most of which are 2-smokes, have electric rad fans. However, they also use a temp sensor to only engage the fan when the coolant gets hot enough.

So it should be possible! theoretically. I doubt a small fan would require much power so the stock stator is probably up to the task. Best to research tht though.

Maybe you could make a trials fan part fit the CR?

Another idea would be to see if you can find larger radiators, and jet a bit richer to cool the engine temps.

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Has anyone put a cooling fan on a two stroke? I am on the search to make my CR 250 run cooleron slow tech trails... Would you need an aftermarket stator or what?

Or a lighting coil plus a voltage regulator. Or a battery that just runs the fan.

Maybea gear change for less clutch use would help the engine keep cool.

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Yeah I have Rekluse z and makes the motor run noticeably hotter. I use Engine ice coolant, already a little rich on pilot...

The oversized radiators are Deff on the list once I can afford them. I imagine a fan could be picked up relatively cheap though.. Also im thinking of an on/off handlebar switch if a temp sensor is to tricky.. Hmmm

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If you think that is hot, try a 4T in the tight suff. I like watching the hondas blow steam in HS races.

A handlebar switch would work, with a battery and a computer fan. Just realize the fan may die if it gets really wet.

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One thing I didn't know until I had to test my fan a long time ago is that the stator on my 2-stroke Gas Gas Trials Bike puts out AC current while the fan needs DC current so along with the thermostat, the bike is equipped with a small inverter that feeds 12V DC to the fan only.

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also some type of capaciter would help as well

as it holds the charge and will be more stable power out put

as the fan drains from the capacitor instead of straight off teh source

so meaning

your stator is chargeing the capacitor then the fan is draining the capacitor

witch intern should work out to be a more stable charge rate

and a constant same level current with out fluctuations

im not a electrcian so dont hold me to all that

but i have also thought of this idea

and this was 1 of my solutions to loseing current

im probly completely wrong but its worth a try and it might be a good idea

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I would run a Trail Tech inline radiator temp sensor ( $45 ) wich has a nice handlebar mounted LCD display( you have to make the mount or find a spot) and has it's own battery that lasts 4-5 years.. A powerful 120 mm CPU fan can put out 253 cfm but that is a bit over kill and draws too much power..... The powerfull fans are 38mm thick ( too thick for mine) and so I had to find the most powerfull 25mm thick fan in 120mm frame and it was 150 cfm....... You could put a hardcase lipo battery in a fanny pack or make a battery mount someware on your bike and run it threw a switch to your fan.... When your bike starts to get hot just hit the switch, that's what I am doing with my CRF ... I have a 8000mah battery wich could run a 190 cfm fan for 4 hrs continuous and it weighs less than 1.5 lbs.... So if you were to go with a battery half that size you would probably be ok... Lipos can handle 300-500 charge cycles and are the most powerful batteries so adding a powefull light would be no problem...You need special lipo charger/balancer and a voltage moniter so you don't run your pack too low... I have links to pics of my temp mount in another thread .. They are carbon fiber and simple to install...

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Hey Rearwheelin.... you've pretty much hit the nail on the head with what I would like to do with my bike. My original plan was to add a battery just for a tail/brake LED (I have a separate battery op head light), but then thought i wouldn't mind adding a rad fan...

So then... what brand battery and charger are you running? Any idea what the amp draw of the fan is? I like the durability of the SPAL 4" puller fan, but it may draw too much power, even for occasional use.

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Here is a link to pics of what I am doing with mine..... I have a build thread started and I am waiting for my fan to come in to wire everything together...... I will send some links to batteries and chargers n other stuff you will need ... I will post them here... The beauty of lipo is once they are charged they stay charged for years !! and they are fairly inexpensive depending on the C rating/ discharge rate...... You could take a pack than ways only a few ounces and power a fan and more Hi power headlights that you could ever possible fit on your bike ! Cheers:thumbsup: http://m1208.photobucket.com/albums/rearwheelin/Mobile%20Uploads/

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Sorry I didn't address the fan, I havn't read anything about the one you have... Mine will put out 150 cfm at 1.74 amps ... My 8000mah pack will run it in theory for 3.47 hours continuous..... 2.87 hours with a 5000mah... My fan doesn't seem very efficient but it does throw the best air for it's size in 120mm... Her are links to battery stuff you will need...

Battery power for moto*

5000mah hard case 20c

http://www.hobbyking.com/hobbyking/store/%5F%5F16768%5F%5FZIPPY%5FFlightmax%5F5000mAh%5F3S1P%5F20C%5Fhardcase%5Fpack%5FUSA%5FWarehouse%5F.html

Charger

http://www.hobbyking.com/hobbyking/store/%5F%5F5548%5F%5FIMAX%5FB6%5FCharger%5FDischarger%5F1%5F6%5FCells%5FGENUINE%5F.html

Moniter

http://www.hobbyking.com/hobbyking/store/%5F%5F7390%5F%5FHobby%5FKing%5FLCD%5FBattery%5FDetector%5F6S.html

My build thread....http://www.thumpertalk.com/forum/showthread.php?t=1016159

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Thanks! Never saw that site before. For that charger though it says power supply not included... what's up with that?

Here's the SPAL fan I mentioned. It's an OEM quality automotive/motorcycle fan that's supposed to handle dirt bike abuse duty well. http://www.spalusa.com/store/main.aspx?p=itemdetail&item=30103018

They can be had on eBay for about 35 dollars IIRC.

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Thanks! Never saw that site before. For that charger though it says power supply not included... what's up with that?

Here's the SPAL fan I mentioned. It's an OEM quality automotive/motorcycle fan that's supposed to handle dirt bike abuse duty well. http://www.spalusa.com/store/main.aspx?p=itemdetail&item=30103018

They can be had on eBay for about 35 dollars IIRC.

There are very few lipo chargers that you can plug into the wall, the power supply that is missing they are referring to is 12v... I use a power inverter at home and they sell thoughs too or you can clip to a car battery.... I have 2 $120 lipo chargers and run a power inverter... The link to that particular charger was a inexpensive one, I found this site after spending bucks on battery stuff here in the states and now Hobby city has a U. S. warehouse.... Lipo batts need to be used with great care , they cannot be over charged or run to low or they will become puffed or catch fire ! That is why they don't plug in the wall..... They are amazing batteries to say the least though.... Those links were to get you there it's up to you to pick the poison ... Ha ha

The fan you want was just like the KTM fan in there kit.... Looks like it's allmost 150cfm free flowing at 2.2 amps ! It pulls 2.5 amps if you were to put that fan against a solid object and pull no air so getting it in the right spot will be key and it has a brushed motor compared to a CPU fan that use brushless motors for the most part wich are 3 times as powerful as brushed.... My opinion on that fan is they will hold up better in the environments we ride forsure but it will use more power and draw less air than a powerful computer fan... It will be more difficult too install and heavier also....A CPU fan will pull more air threw a bigger area also !

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For kicks and giggle these are the best batteries on the planet..

TP7700-3SPP65 7700mAh 3-Cell/3S 11.1V 12C 65C 130C 92.4A 500A 1001A 626 50 x 44 x 136 $219.99 Yes

Link to made in USA lipos , these are the worlds best and can deliver 1000amps.... 500 amp continuous... *Way more than what we need for our app , but if someone concerned about weight and wanted a powerful electrical system strong enouph to start 10 bikes at the same *time, these batts are the best.....http://thunderpowerrc.com/

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should be able to make a ktm fan work. theyre hell of alot better than computer fan

I agree , I had one in my hands... My concern was the bracket I was going to need to make and getting it close enough to the rad for it to do it's job well with out diging in to my rad in a fall over or from rad movement.... They have acoustic silicon vibration dampeners that go on the frame of the CPU fan allowing you the but the fan directly to the rad with no worries of it diging in and will draw 100% air threw rad .....I Agree the KTM fan way more durable

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I have a friend who put a computer fan on his 300 KTM last year and did a 24 hr mud race...works fine still.

Run a zip tie through the bolt holes and through the radiator. Put another zip-tie on the protruding end and cinch tight. Cut excess off. Do this for all 4 mount points.

He put a toggle on it instead of a temp sensor so he controls it manually. Just have to remember to shut it off when stopped but it is hard to miss the whirring/fan noise when all bikes are shut off.

Edited by MX813

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I have a friend who put a computer fan on his 300 KTM last year and did a 24 hr mud race...works fine still.

Run a zip tie through the bolt holes and through the radiator. Put another zip-tie on the protruding end and cinch tight. Cut excess off. Do this for all 4 mount points.

He put a toggle on it instead of a temp sensor so he controls it manually. Just have to remember to shut it off when stopped but it is hard to miss the whirring/fan noise when all bikes are shut off.

I checked into a thermal switch, I would need to modify a rad to thread one in so decided after I get the bike going with just a LCD temp display and a switch to turn the fan on manually as needed.... I want to find out what temp my bike runs at with easy rideing before I decide to go thermalstatic switch.. I herd the KTM switch doesn't turn on till 220 degrees.

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I have a friend who put a computer fan on his 300 KTM last year and did a 24 hr mud race...works fine still.

Run a zip tie through the bolt holes and through the radiator. Put another zip-tie on the protruding end and cinch tight. Cut excess off. Do this for all 4 mount points.

He put a toggle on it instead of a temp sensor so he controls it manually. Just have to remember to shut it off when stopped but it is hard to miss the whirring/fan noise when all bikes are shut off.

My friend did the same thing with his 09ktm300xc. He uses a toggle switch on the bars to control it. And yes everybody looks around saying what the hell is that noise when the bike shuts off. Seems to work good though, that bike used to over heat constantly but not now.

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The KTM fan kit fits almost like it was designed for honda CR/CRF's. The kit comes with a ~4" Spal fan with a shroud, temp switch, and electrical connector. I had my local radiaor shop weld in a threaded bung (which I made) and 4 flat tabs (I made these as well) with holes in them to mount the fan. The temp switch does come on at around 220-230 so I switched it out with one from a suzuki ltz400 which had the same threads but comes on 20-30 degrees sooner. I had already had a lighting setup on my bike so it was not difficult to tie into. I didn't catch what year CR you have but if it is 2002 or newer, you can jump into the power from your RC valve and it should have barely enough juice to run the fan without having to furher modify your electrical system.

I never fealt the need for it on my cr250r, but can verify that it will fit. Here is a pic of it installed on my CRF450R (512cc)

crf450rfan.png

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