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KTM Radiator Fan on 03' 400FE??

sueyoulater

sueyoulater

Joined Apr 2005
48 Posts | 0+
Eugene, Oregon
Does anyone know if the KTM Radiator fan will work on 400FE. Bad overheating problem unless I am moving. What are chances of engine damage from first over heat? Is there a thermostat I should remove? I am a brand new Bergite. Need all the help I can get. :?:
 
hi sue (have i put 2 & 2 together and made 5?)

i trust that you have bought the bike used. and that it bubbles up and spits the coolant out? to check if you have a headgasket gone start and run the bike full of coolant but with the cap off. very tiny bubbles will keep making their way out and up through the coolant.

i had this 2 years ago. i pulled the head off and using some 'wet 'n dry' paper wrapped around a wooden block, and soap i rubbed down around the head just cleaning it up. cleaned the block up the same and then wiped down the bore wall pretty sharpish to stop any grit getting down the side of the rings.

for the second part, i fitted a new head gasket and torqued it down more than the factory figures recommend. see the 'owners doc' at the bottom of this post for slightly higher figures.

anyway, that cured it. you shouldn't be boiling up a 400 i don't think. you can try re torqueing the head down as a first cure.

regards

Taffy
 
Sue

I have seen the fan mounted, but very crudely.

What type of riding are doing?

I ride in the Rocky's in altitude with lots of elavation change and this is what I've found to control heating issues.

Try to keep your engine rpm higher so that you are moving the coolant through the rads at the highest rate possible. Lugging your engine creates more heat and cirulates teh coolant slower.

Avoid clutch usage. Fanning the clutch is a sure way to add engine heat.

taffy may have the answer for you and on the mechanical failure topic try a different rad cap, they can fail.

fry
 
The KTM fan will not work, there is not enough room. I have just mounted two 92mm computer fans on my 04 FE650e. As of yet the setup remains untested. Perhaps I will have the results next weekend. My biggest concerns are actual effectiveness and durability (due to water intrusion). The fans will move 250 cubic feet of air per minute, this should be great at low speeds. The big question is that will it be enough at higher speeds. If it works it will be an inexpensive modification. $150 with the BOSS radiator guards being the most expensive parts.
 
I am a college automotive instructor and we teach (sounds weird) that removing a thermostat will lead to overheating quicker because the coolant can move too fast, thus not transferring any heat! I have seen it for myself on a few race applications and a restrictor cured the problem in both cases. As far as the "physics" behind this, maybe someone else can shed some more light. Volvonut
 
Volvonut,

You are right on the money. What happens is that the coolant flows too quickly through the heat exchanger (radiator), and, as you said, does not have time to dump the heat. So, what ends up happening is that the coolant becomes heat saturated, and then boils.

The new husaberg's have a thermostat, where as the 04's on back do not. My 2004 550 overheats very seldom, usually when I'm having to abuse the clutch in tight races. What I have found as the cure most of the time is (as another post pointed out) is to keep the rev's up enough to circulate the coolant a little faster. Just the opposite of what's happening in the above paragraph.
 
Excellent info Daleo and Volvonut. I was considering removing the thermostat for complexity reasons and have ruled that out now. And now I want to go thrash them in the tite stuff!!!!
 
I have been running the two 92mm computer fans on my 04 550FE for almost a year now. No problems with durability on the fans, I replaced one due to a cracked fan blade from a stick lodged in the guard. They are also behind a aluminum radiator guard. They help, do not completely cure the heat build up in the slow going. I run Evans waterless coolant and a temperature gauge, when the temperature gets above 240 on 90+ degree days I pull over and let it set a while. I don't have any overheating problems if I can keep it above 15 mph.
 
I doubt that removing the thermostat would be detrimental in this application. Just my 2 cents. It would easy enough to experiment with just the same.
 
I am not worthy...I am not worthy.... You guys seem to understand the problem fairly well. I just need the fix. I do not think my bike has a thermostat. Thermostat does not show in the manual as I recall..

I like the idea I saw posted with regards to using an overflow bottle. KTM makes one in the hard parts catalog, but one post I read talked about pirating a Yamaha overflow/recovery bottle under the seat. The fix looks good/hides well and will at least save the fluid from total loss on an overheat.

I was on very rough trail and slow speeds, fanning the clutch and not enough air over the radiator. I thought a fan would fix the problem, but the KTM apparently won't fit. We shall see. There is an Italian outfit called SPAL that makes a 6.5 and 7.5 inch cooling fans for motorcycle radiators. I assume they are water proof. If I hit upon anything, I will announce.

Thanks you for all the input. By the way, the bike is a left over BRAND NEW 2003 FE400 off the floor from G&G in Albany Oregon. :)
 
As Daleo pointed out the 03's do not have a thermostat. It was introduced in 05. I have not experienced any overheating on my 05 FE450 so far (20 hours) . It would be easy to fit an 05 thermostat to an 03 as they just splice into a hose. If you ride a lot of tight technical stuff perhaps a Rekluse autoclutch might help keep things a bit cooler as you wouldn't have the extra clutch abuse heat to contend with. Also slightly richer jetting could help.
 
Sacberg,
I am running the Evans coolant as well. Where did you find your temp guage?
 
Just wondering, would Water Wetter work to keep the temps down? I know that road race bikes use it because of the glycol coolant spill hazards and it is said to keep engines cooler (I never ran it). Only problem is the lack of freeze protection. I know Evans coolant was mentioned and I am not familiar with it but if it about the same stuff then sorry.
 
Water wetter gave me no apparent advantage, the same can be said about Engine Ice. The only advantage of Evans is that you WILL NOT boil over and run basically a zero pressure system (which is nice). The boil point of Evans is 370F at zero psi. I would imagine you would sieze before you boiled over using the factory pressure cap. That is why it is a good idea to monitor the actual coolant temp..
 
I concur, I got NO improvements using Water wetter or Engine Ice before switching to Evans. One benefit of Evans it eliminates the need for an overflow catch can, you engine will go before it will boil.
 
I would like to know the wiring diagram for the computer fans. Where do you connect it on the bike's electrical circuit and do you add any type of resistors? Computer voltage is 12 volts (ok so far) and the amps delivered to a computer fan is below 0.2A (err....)

Also it seems that Evans is 100% Propylene Glycol. Why not get some automotive coolant like stock Dexcool (although I have read it plugs up the hoses).

Just found this on KT:

http://ktmtalk.com/index.php?showtopic=97608
 
The fans are fused through the battery and switched using a common automotive fan switch. Dexcool sucks and has a boil point of about 230F.
 

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