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you prob wouldnt notice it. It rarely comes on. You need to let the bike idle for a few minutes in order for it to come on. Some guys dont even use them.
 

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i have a 2004 trx450r and my fan to my knowledge has never come on how can i wire it to b on all the time?[/b]



You can check to make sure it works by grounding out the wire that goes to the thermostat housing.
 

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If you unplug the wire from the temp sensor. Its located just below the head cover on the front of the engine on the left. If it is just touch to a ground the fan should come on.
 

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I only notice mine come on if im riding the piss out of it
 

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If you unplug the wire from the temp sensor. Its located just below the head cover on the front of the engine on the left. If it is just touch to a ground the fan should come on. I put a switch on the wire so I can turn it on when I'm doing a lot of slow riding in rough terrain or riding with older folk that are riding their fourtrax's in 3rd.
 

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riding with older folk that are riding their fourtrax's in 3rd.[/b]
My bike Idles at that speed, I race my cuzzins 250 and the deal was, I dont tuch the gas and he only goes to 3 gear, So I turned up my Idle a bit and was in 5th idleing and he was pinned. pretty funny crap.

my fan only comes on when idleing for more than 5 min also
 

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Yah..my fan hardly ever comes on..Everytime me and my friends go ride ..the LTR and YFZ fans are on ALL THE TIME...and mine hardly ever comes on.. But when it comes on you can usually feel that burst of warm air shooting at your leg..
 

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Don't forget the engine is already liquid cooled. I don't ever recall the fan coming on when I had my '05. Even after idling in warm weather.

However, I was working on my '07 in the garage and got the fan to come on......but it was 100 degrees outside and even hotter in my garage.

Jetting also affects engine temperature. If your jetting and coolant levels are correct then don't worry about it.
 

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after a two hour ride in some hill climbs and slow trails. my came on. the 450r engine just runs warm, nothing wrong with that. the fan will do its job, but if u want to make sure ground out the wire like others have mentioned.
 

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What else determines when the fan comes on but the temp sensor? because i unplugged my temp sensor and the fan still wants to run all the time. I have had it grounded, but want to go back because i think mine runs too cool now. Never gets over 180F.. Why is my fan still running after unplugging the wire from the temp sensor?
 

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What else determines when the fan comes on but the temp sensor? because i unplugged my temp sensor and the fan still wants to run all the time. I have had it grounded, but want to go back because i think mine runs too cool now. Never gets over 180F.. Why is my fan still running after unplugging the wire from the temp sensor?[/b]

There are 2 wires that operate the fan. 1 is the hot wire that provides the power to the fan the other wire goes to the thermostat. The contact inside the thermostat is normally open. When the engine gets hot enough the contact closes (just like a light switch does when you turn it on) and allows the circuit to be complete (lets the power travel through the motor to ground). If you have the wire pulled off of the thermostat and it still runs, then trace that wire that goes to the thermostat all the way to where it ends it has to be grounded some where or it would not be running.
 

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Anyone know a part number on the sensor!? i cant find it anywhere or the number.[/b]
I had the same problem as you. It is called a thermo unit >>Thermo Unit click on "engine and exhaust" then "cylinder-head" and it's #15
 

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I had the same problem as you. It is called a thermo unit >>Thermo Unit click on "engine and exhaust" then "cylinder-head" and it's #15
My 450r runs between 23o - 250 degrees in about a 40 min ride I have to pull off some where let it cool down, my radiator will be gurgling inside! I have replaced fan, thermostat, and temp sender still no fan! I am in the process of goin threw the wiring harness checking for broken/ damaged wire.. any ideas?
Also I took my buddies cdi box and switch out mine still no change.. don’t know if this is important but I have 13-1 piston stage 2 hot cam and run on 110 race fuel in summer and 91 with octane boost in winter
 
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