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Posted by: jaybeecon55
I was questioning the fan on my Eiger a while back - had some motor work done and was worried about it overheating. It seemed like the fan never came on. Finally called the service dept and found that the fan is designed to come on at 246 degrees. Parked it in the garage at a high idle and stuck a cooking thermometer in between the cooling fins. It took a long time, probably 15 to 20 minutes and the motor sure 'felt' and 'smelled' hot but sure enough - right at 246 the fan kicked on. Once the fan forced air through the oil cooler it dropped way down in a few seconds. I don't worry about it anymore - although I do have this fear that my wife will find out where her cooking thermometer has been.
Jaybee
Posted by: Kawi650
How can you run a 350 hard enough to make the fan come on? LOL First letting it idle will not get it hot enough. The fan will run a little but not too often. If you are like me I have a switch that turns my fan on and when the switch is off it turns on when it needs to. Very easy to do all you have to do is give it a different power source from the battery and have a 2 way switch from that to the stock wire. I feel your bike doesn't require a fan... it doesn't need the cooling other bikes need.
Posted by: Kawi650
The 350 has to be running and work constanly for the fan to come on and i found once you stop/ let it idle the fan will shut off in seconds. If a 450 fan comes on it also could be an indication of a lower oil level. Dragging kawis, plowing snow etc.. for a long time would get the fans on a 450 easier than a 350; the 350 fan will come on after a while. Also a clogged oil cooler would cause the fan to come on.
Posted by: hounddog
I have an '02 Rancher and it doesn't come on very often. It will more than likely come on at slower ground speeds, but higher revs, such as mudding or deep snow.
Posted by: Starky
Get stuck in sand or even snow. After working it back and forth for a while the fan will come on. You'll smell it when it gets hot enough.
Posted by: reconranger
Just be patient! The fan will come on eventually. Remember that it is winter, too.
Posted by: snowbuster
i got a rancher. its fine (your fan). mine comes on once in a while, noramlly hi revs in low gears make it come on. but once my fan comes on i let it sit and cool its self down. and jsut because your fan comes on doesnt mean its over heating. the red light on the dash will tell u when that happens.
Posted by: Chilly
Mine comes on fairly often, but most of my riding is slow work under a lot of load, so airflow through the cooling fins isn't as high as it could be. I was hauling some trees out today, and even at -15C air temp the fan came on for about 5 minutes at one point.
Posted by: Chilly
The temp sensor for the fan unit looks at only oil temperature. Ideally , if it were a liquid cooled engine, it would look at coolant temp, but the oil is really the only consistent source it has to look at heat levels. Having said that, in a liquid cooled engine, oil temperature usually runs about 10-15 degrees C hotter than coolant temp, so that should give you some idea what the actual engine temperature is.
I'd be concerned about the exhaust glowing red, it's an indication of an overly lean condition. Fuel does act as a cooling agent in an engine, and what doesn't get completely burned cools valves, piston crowns, etc. If the exhaust pipe is glowing red hot, the valves are dangerously hot as well. All that keeps them from burning under this kind of condition is the contact with the valve seat, which acts as a heat sink to absorb excess heat. If a valve is set slightly too tight, it will be prone to burn.
In today's world of cleaner-burning engines, the trend is towards leaner mixtures to help meet more stringent emissions standards. Liquid cooled engines are better able to cope with this situation, having better cooling consistency throughout the engine water jacket. Air cooled engines, while enjoying greater simplicity and IMO reliability, tend to have hot spots which are hard to control effectively. The leaner mixtures use a higher air-fuel ratio, which means less unburnt fuel to help cool the internal parts of the combustion chamber.
I'd advise you to slightly richen the mixture until the red exhaust goes away. As to whether you need to richen the idle circuit, the midrange, or main jets, that depends on where the engine is running too lean. I'm guessing your spark plug is going to be pretty light colored as well. Check to make sure it is the correct heat range plug, mine had been changed to a colder plug, and was dark as a result.
Posted by: grizz76
I had a 350 Rancher a couple of years ago. The only time the fan came on was when i would ride it in a low gear for a few miles. I was looking for a new hunting location at slow speeds. I wondered if it even worked, and was going to have it checked but it eventually came on. I never overheated while I had it I've had my grizzly for around 6 or so months and I've overheated several times due to mud covering the radiator.
Posted by: steadyfreddie
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Originally posted by: Kawi650
How can you run a 350 hard enough to make the fan come on?
Yeah I don't get this either. My fan comes on when I am trying to pull KVF's out of the mud. LOL.
Mine comes on as needed, which is usually when I am dragging the road and my driveway with the extra heavy drag I have.
Posted by: steadyfreddie
Same here Chilly. I was plowing snow this weekend, it was about 1 degree out, and the fan came on a few times. I was plowing in 2nd and 3rd gear. Fresh oil, and correct level too, it's just the way these Hondas are. The fan's there for a reason, and I am glad it works.
Posted by: natron1
Although you could have a problem I doubt it as you are in michington and the are is still cool or cold enough as it is here in Pennsylvania. To cool the radiator and engin enough. Wait till hot summer to worry if it still does not come on. IHTH
Posted by: goins
my buddy has a rubicon and i think that is jsut the way hondas are, his fan rarely goes on. as long as u don;t smeel nothin i think u will be fine, enough air get forced through there when u are riding that it keeps it cool without the fan. but it prob wouldn;t be a bad idea and make sure it does work.
Posted by: sok
i have a 03 rancher 350 even after a 20mi hard ride and let idle afterwards fan has yet to come on.dealer says will not come on only if its overheating.think i should check by grounding where wire goes to sencer?how do i do this?
Posted by: sok
you can run a 350 hard if you don`t stop to check your makeup every 5mins.
Posted by: outdoornut
I have seen exhaust glow with over rich conditions. I changed the cam in my mustang and there was not enough vacuum to keep the power valve closed. It was dumping fuel, the headers glowed bright cherry red. I also thought it meant lean, but not always.
Posted by: bcalhoun
I was wondering about my fan also. Honda 450. Where is the sensor for the fan? Is it located to read oil temp? The reason I ask is the head pipe will start to glow red sitting still at a high idle. I thought it would be enough to make the fan come on. Should I worry about the pipe. I haven't noticed it riding. Since it's air cooled is this normal.
Posted by: bcalhoun
Thanks for the reply. I'm going tomorrow to see about a jet kit. I think the atv was set up for a different location. I'm assuming my local dealer would have the right size jets for our area. Could it be that it was set up for a different area. I bought it used of course.
