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09 Kfx450r Fan will not turn on

6K views 20 replies 6 participants last post by  blue99stroker 
#1 ·
What’s up guys. Just bought an 09 kfx450r two days ago. The fan will not turn on when I press it. I’m not sure why. Also, I changed all the fluids with filled them appropriately. And my quad was idling for 10 mins and the heat light came off. I let it sit then i ran it up and down the road and it shut off. Any ideas why the fan won’t turn on and why it overheated while idling for 10 minutes? Let me know please currently taking it on a riding trip to WV and mostly concerned with the fan issue once i get into the woods. Thanks!!!
 
#2 ·
The fan is electronically controlled there is no switch unless someone added one
.
The light on the left is the FI or temp
 
#6 ·
Someone definitely added that.
If you start your bike and let it idle it will increase in temperature slowly until it reaches about 212 degrees Fahrenheit. At that time the fan comes on and it will stay on until the temp is back down to about 200 degrees. The fan shuts off and the temp starts to rise and the process repeats. If the fan wont come on, you will definitely destroy the engine quickly.



Sent from my SAMSUNG-SM-G935A using Tapatalk
 
#10 ·
taking advantage of the topic because I have the same problem that does not turn on the fan wanted to ask a question in the photo I send attached on the top of the engine behind the marked cover does not have a thermostat like in the KXF400? Can't this thermostat be broken by not opening the water circuit and then not turning on the fan?
It's just an idea and I'll see if next weekend I can check if in my case it's also the relay or thermostat because the temperature sensor is good and if I disconnect the temperature sensor plug the fan works as soon as I turn on the key
 

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#12 ·
hello, after testing the relay is ok, the fuse is ok, and i don't understand what's going on because when i unplug the sensor plug the fan turns on ... i think it will be the control unit that is not working well or the sensor that doesn't work ...
I will take the temperature sensor and test as soon as I have time.
or other suggestions ???
 
#13 · (Edited)
The fan should come on at 200~205 degrees F & turns off at 190 degrees F...sometimes the motor just doesn't get hot enough to turn the fan ON..but check the water temp sensor to functioning correctly...!!

Also remove your radiator cap & check your radiator coolant level...Air in the system will prevent the coolant to circulate, air around the Temp sensor will prevent it to function...keep the cap off & burp any air out of the cooling system...squeezing the lower hose & running the motor for a couple of minutes with the radiator cap off..usually does the trick...
 
#15 · (Edited)
hello, after many test the fan already works.
I think it would be air in the circuit, I took the sensor I tested and it was working, I assembled I took the air out of the circuit as you said to do and the fan went back on.
thank you very much to everyone for the tips and suggestions to solve the problem.
where I can put some videos of the roads we make with the bikes??for you to see what kind of roads we go
thanks
 
#16 ·
Also taking advantage of this post and my fan still wont turn on. Confirmed that fan does work, burped the system and put blue ice in there, new relay, fuses are good. New water temp sensor. Fan still not kicking on. My vapor trail tech shows the engine going up to 220 degrees and fan wont kick on. When I unplug the water temp sensor the fan stays on. Any ideas? Dont know what else to do
 
#17 · (Edited)
You mean Engine Ice coolant..

Is your ECU OEM or after market (Procom)...??

If it's an OEM ECU does your F.I/water temp dash light remain ON for more than 3 seconds...??

Have you removed your Water temp just enough to see if any coolant comes out with the radiator cap "OFF" ...?? An air bubble might be there that's stubborn & doesn't remove by burping easily...
 
#19 ·
hello, is it possible to put a thermostat with a fan trigger to turn on at 92ºC and turn off at 87ºC?
if possible where can i get one?
here I drive a lot at 1st and 2nd speed and I use the clutch a lot and I need the clutch not to warm up so much, or suggestions for better cooling of the clutch
thanks
 
#20 ·
No...thermostat will cause the head to warp due to reduced flow of coolant...!

Cooler clutch is to get an oil cooler...if you can find one...??

Check the wires with an ohms meter of your fan circuit fuse box & relay..could be a broken wire or loose connection somewhere in the wiring harness...
 
#21 ·
If the clutch is fading it’s time for an oil change...kfx’s are really hard on oil because of the small sump.

Or you need to use a better quality oil that doesn’t shear so fast and cause worse clutch feel.
 
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