overheating problem need help!

[300racer]

I am having problems with my 450r overheating! When it gets hot the fan doesn't turn on and the temp light doesn't either! I have tested both of them and the fan motor is ok it runs and the temp light works also. does any one know what the prob could be? and is this the reason why my quad is overheating?

how do you know its overheating? engines get hot you know

[RedRacer44]

I'm wondering the same thing. Whats the initial clue that your bike is over-heating?? My motor runs pretty hot and the fan kicks on every now and then but its never over-heated.

[DirtDevilBT]

Well, my fan never comes on but I run at pretty high speeds most of the time. I only found out it was good when I let it idle for 13-15minutes. And even when it came on it only stayed on for less than 30 seconds. Strange, but I have not had any "overheating" problems nor have I heard of any. :confused: What are your symptoms?

[trost66]

i've seen people have there over heat but it was becuase of the number plate on the front. Wasn't allowing enough air. They took the plate off and it was fine.

[kargaaro]

It will boil out the overflow when it overheats and spew white smoke. try to get the mud all out of your rad when mud riding.

[300racer]

well I know it is over heating because the antifreeze is blowing out of the over flow and the temp light didn't turn on and neither did the fan. I do clean the radiator very well after every race. I did have tape over the front bumper but I don't think that would be a problem. I let is idle for a while the yestarday and the fan didn't' come on agian but that be because it wasn't hot enough to come on cause I didn't let it idle for 13-15 min.

[kargaaro]

when is the last time you changed your gear oil. I think that's what caused mine to overheat. The oil was a little burnt up and the clutch ended up going in a mud GNCC race. There's only a half quart in there and it needs to be changed often. I learned the hard way.

[dunebuggie66]

did you change your antifreeze recently. maybe you put too much in and the excess is blowing out of your overflow. that happened to me with my 520. and it still blows a little out here and there.

[300racer]

I raced 2 gncc's on my gear oil. I did also change my antifreeze also I might have pu to much in. those could be the problem! I will have to change the gear oil and see what happens.

Have you removed your keyswitch?

[300racer]

no I don't have it removed I am going to let it run for 13-15 min tomarow and see if it overheates and see if the fan comes on cause I let it idle for about 5-6 min and nothin happend and thats why I thought the fan wasn't workin. but I know for sure the the temp light isn't working becaue I was less than a mile in the race when it overheated and the light wasn't on then.

[markk]

Does anyone know how to test a temp sensor, Its the little eletronic plug that screws into the thermostat housing. I watched 300racer, and his dad take the thing apart, and I wondered if the temp sensor was bad, that would keep the light from coming on, as well as the fan. ???Wouldnt it??? Or am i just dumb!



If so does anyone know how to test a temp sensor?

[hondaryder42]

here is a simple test for you to try. this will not tell you if the sensor is working but it will tell you if the fan motor is working. also i believe the warning light and fan motor are two different sensors. take the wire off the sensor directly in front of the engine. (i dont have my machine here at work) but it is easy to find. ** single wire plugged onto on sensor going into rad **

then make yourself a jumper wire so you can ground the wire. once you start the bike if this wire is grounded your fan should run constant. it is a quiet fan so you will have to feel the air move.
if it does not run then your fan motor is shot. if it runs the fan motor is ok. once you know the motor works just let it idle long enough to get hot. now if it does not work plugged back onto the sensor after you get her nice and hot then the sensor is shot

hope that helps

[markk]

we found out that the fan does work, But we ended up taking a 12v battery charger, and running it with it for a few seconds just to see if that was it. Thanks for the help!

[jacksongncc450]

Do what hondaryder42 said to do and wire it up like that so the fan will run all the time thats what we did to my race bike and it never gets hot.

[Kauai450]

Did you check the hose that runs from the overflow to the radiator
Had a similar problem and I thought it was overheating ,but it turned out that the hose had chaffed though by rubbing on the fan, and wouldn't leak at idle but would after awhile of riding (I guess from the vibration. Found it accidently when checking the bottle and I shook the hose.
To test the switch or any temp activated you have to know its
working temp. The switch will close providing ground for the particular circuit its in, This case the fan. You can check it two ways 1) With a volt /Ohm meter switch should have continuity to
ground at its "Working Temp" 2)Or you can install a test light in series between the wire connector and the sensor run the bike and when "Working Temp" it reached test light will illuminate.