Thermostat

teal_210 · Jan 26, 2012

Anyone running one on a mx based 450?

I'm sick of leaving my bike running all day to keep the water temp up. With the powder that we have right now, water temp drops to 60-70° fast. Which, on my '11 Crf results in large amounts of gas in the motor oil. I've been blocking one radiator 100% of the time, and both when in powder, but constantly monitoring temps is getting old.

Would like to keep the water temp up around 150-170.

So... who's running what?

Rush44 · Jan 26, 2012

I'll have Randy respond to this. He is running a thermostat on his KX450 and was able to raise engine temps to 140 degrees. We are going to make some pictures of the install and setup.

Mtn. Muncher · Jan 26, 2012

I have KTM thermostats on my 2012 KX 450’s and all I can get them up to in the deep snow is 120o max, most of the time they are under that. I think I am going to try pinching off the hoses on one of the rads. If that does not work I am going to eliminate the by pass on the thermostat housing and drill a very small hole in the thermostat so the hot water will reach it so it will open when up to temp.

Allen

mtn-doo · Jan 29, 2012

I have the same set-up on mine. I reach 120 to 130 in the fluff and 140 to 150 on the road. It is still a little low but it does raise your temps 50 degrees across the entire range. Helps for sure but needs a little more.

carbondaddy · Jan 29, 2012

Where does the thermostat go on your kx? What thermostat do you use?

mtn-doo · Jan 30, 2012

carbondaddy said:
Where does the thermostat go on your kx? What thermostat do you use?

The thermostat i am using is KTM #59435013044, 70 degree C crack temp. It installs in place where the factory aluminum Y is. Main line from your Head in the bottom and the Y out the top to each radiator.
__________________

cr500afx · Jan 30, 2012

Two ways to go.
1) Try an inline M456-1 thermostat. It's set at 130-140 degrees.
Description: https://www.altfuel.com/cgi-bin/commerce.cgi?preadd=action&key=M456-1
Buy for $ 20 at: http://www.helmarparts.com/product_p/m456-1.htm
Then go to local hardware store and get 5/8 or 3/4" nipples (depending on size of your radiator hose) and install on your radiator hose coming out of engine but before your radiator.

2) Try a thermostat bi-pass. Run hot coolant from engine to bi-pass thermostat and back directly to engine. On Bi-pass side of thermostat run coolant from bi-pass to radiators and back to bi-pass. Bi-pass is set at 170 degrees.
Buy for $ 77 at: http://www.summitracing.com/parts/HDA-163/

I have run both and with good luck on 2009 CRF450R turbo.

teal_210 · Jan 30, 2012

cr500afx said:
Two ways to go.
1) Try an inline M456-1 thermostat. It's set at 130-140 degrees.
Description: https://www.altfuel.com/cgi-bin/commerce.cgi?preadd=action&key=M456-1
Buy for $ 20 at: http://www.helmarparts.com/product_p/m456-1.htm
Then go to local hardware store and get 5/8 or 3/4" nipples (depending on size of your radiator hose) and install on your radiator hose coming out of engine but before your radiator.

2) Try a thermostat bi-pass. Run hot coolant from engine to bi-pass thermostat and back directly to engine. On Bi-pass side of thermostat run coolant from bi-pass to radiators and back to bi-pass. Bi-pass is set at 170 degrees.
Buy for $ 77 at: http://www.summitracing.com/parts/HDA-163/

I have run both and with good luck on 2009 CRF450R turbo.

Do you happen to have a picture of the first one installed? Looks like a clean/simple setup.

cr500afx · Jan 31, 2012

Probably won't help you much, but I attached a picture of both the M456 and the Bi-pass thermostats installed on my bike. I don't have a LH radiator on my bike and coolant runs from engine to the rear of the bike thru the M456 thermostat and then thru the Bi-Pass thermostat and forward to my RH radiator and then into the engine. If/when coolant reaches 170 deg then Bi-pass opens and coolant is sent thru a rear tunnel heat exchanger as well.

On a stock bike application I would install the M456 on the engine coolant outlet hose before the radiator. This should get your temps to the low-mid 100's. You may still need to block one radiator off. Not a perfect solution, but should help a great deal from where your at now.

snowboatboy · Oct 5, 2013

Has anyone else used that M456-1 thermostat? Looks like a really simple way to do it. Also wondered if it lets anything through or if it just stops it altogether?

KAWGRN · Oct 7, 2013

early KTMs used a thermostat only in one radiator the other one was the by bypass, so I'm thinking of using the single pipe stat on the return line of one radiator and the by pass stat on the other,I have also blocked off the rads in the powder ,but then over heat on the trail home, 2 Strokes, I say NEXT

sodahucker · Oct 7, 2013

Does anyone know if placing a thermostat without a bypass will damage the water pump, seals, or anything else?

KAWGRN · Oct 7, 2013

I would think you need some sort of flow, maybe a larger weep hole in the thermostat? Im also thinking of putting a valve in one radiator

summitboy · Oct 7, 2013

Here is what a ice racer from Sweden uses on his 500. He uses twin 55C stats. I think it will be to cold. I am in the process of fitting twin 70C stats in my 500. Would be more or less the same as what MtnDoo ran on his KX500 with no bypass. Gonna try it and see what i get. I still like Thermobobs idea and i think with a 1/4 bypass line it will work well. Still waiting for a good size housing from him though for a 70C. The 195F housing he currently has is to big imo.

teal_210 · Oct 7, 2013

sodahucker said:
Does anyone know if placing a thermostat without a bypass will damage the water pump, seals, or anything else?

I used the one that Summitboy posted a picture of last year with no bypass. I had no problems on my CRF, and it was closed probably 75% of the time.

goodtogo · Oct 7, 2013

I am running a thermo bob, the bypass returns right back to the motor
http://shop.watt-man.com/Thermo-Bobs_c4.htm

summitboy · Oct 7, 2013

Lets see a pic of your Bob. I assume u are running a 90C stat. Are you finding it stays hot or is the bypass to big ? I think with a nice small bypass on a snowbike you will get the benefits of having a bypass.

goodtogo · Oct 7, 2013

This is a kx450f ,i am running the 90c the bypass returns into the bottoms of the left rad return

summitboy · Oct 7, 2013

Where are your temps ?

goodtogo · Oct 7, 2013

I cant give you a solid answer. I packed a temp gun around the first couple days ( temp sensor wouldn't fit between the head and thermostat ) and got always a solid 90, from what I could tell. I also ended up taping one rad off so it wasn't such a shock to to motor when the thermostat opens up. I have a new machined temp sensor for this year but I am turboing, so might be a little different cooling needs I was getting way higher numbers than the other guys running the ktm stat.

Thermostat

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