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Discussion Starter · #1 ·
Hey does anyone know if there is another way to purchase a thermostat, other than buying it from Harley. For a 2012 dx they want $157 because its sold w/ housing. This is outrageous WTF. The manual says it requires a special tool to remove it from housing. Whatever! So I guess they did away w/ that and decided to sell a complete assy. Another version cost was 102 a platinum one. Mines was more expensive shit. I have a feeling my thermostat is stuck. No triple sprocket issues. Engine light never comes on, but fans run way to long at around 90deg out side on expressway and may not even cut off. But on a cooler day its all good. I have leds tied to my fan circuit so I can watch things. Radiator is clean, I am also looking at temp sensor and pressure cap. The reason I suspect thermostat is because the gage runs at 210 on expressway and fans are on, then when exiting and coming to stop the gage shows engine temp dropping. When it use to rise somewhat. And on cooler days its ok.
 

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Hey does anyone know if there is another way to purchase a thermostat, other than buying it from Harley. For a 2012 dx they want $157 because its sold w/ housing. This is outrageous WTF. The manual says it requires a special tool to remove it from housing. Whatever! So I guess they did away w/ that and decided to sell a complete assy. Another version cost was 102 a platinum one. Mines was more expensive shit. I have a feeling my thermostat is stuck. No triple sprocket issues. Engine light never comes on, but fans run way to long at around 90deg out side on expressway and may not even cut off. But on a cooler day its all good. I have leds tied to my fan circuit so I can watch things. Radiator is clean, I am also looking at temp sensor and pressure cap. The reason I suspect thermostat is because the gage runs at 210 on expressway and fans are on, then when exiting and coming to stop the gage shows engine temp dropping. When it use to rise somewhat. And on cooler days its ok.
I've tried high and low to find a replacement and even talked to a couple of thermostat manufactures. No luck. Damn HD proprietary pricks. I did score a brand new housing and t stat on ebay recently for $19.99. Likely the best place to look for one. I've seen several advertised. Housing and stat 26740-01K

Ron
 

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Nope. I might have posted that originally. Dimensionally it doesn't work out. It is however a Porsche design but unobtainable. Here is the actual t stat sizes, and they are the same from first v rod to 2017. Proprietory shit that nobody but HD is allowed to sell.
Ron
 

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That's for an 06. I have a 2012, there must be some kind of difference maybe. Like I said he had another one that was 102$ mines was considerable higher. The number Ron has shows to be different. Guess I will be on the look out for one. This should be illegal.

Thanks
Don't think there's a difference in sizes. 26740-01k is platinum and the 26769-04k is the black one. Does that match up Rob?
Ron
 

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I wonder what the negative effects would be to run sans T-Stat, remove it completely, and let the coolant flow at all times.

As long as the temps rise above the REV cutback threshold then I suspect all is good, if that does become a problem,during the cool/cold riding season, Franks special override switch could be used to fool the ECM into normal rev limits.
 

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I wonder what the negative effects would be to run sans T-Stat, remove it completely, and let the coolant flow at all times.

As long as the temps rise above the REV cutback threshold then I suspect all is good, if that does become a problem,during the cool/cold riding season, Franks special override switch could be used to fool the ECM into normal rev limits.
It would work but a restrictor would need to be added. Having too much flow , it will actually overheat most times.
Ron
 

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Discussion Starter · #10 ·
Don't think there's a difference in sizes. 26740-01k is platinum and the 26769-04k is the black one. Does that match up Rob?
Ron
Ron
The parts guy said that mines was more expensive. I though surely that cant be that much difference in the paint color, price wise I mean. And of course they dont have them in stock so u can compare. I wonder if our European Riders can get the stat only.
 

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Ron
The parts guy said that mines was more expensive. I though surely that cant be that much difference in the paint color, price wise I mean. And of course they dont have them in stock so u can compare. I wonder if our European Riders can get the stat only.
No. Harley parts lists are pretty much std across the board. They list the same 2 part nos in the UK, one for platinum and one for black with a £54 premium for black. It is not the first time I have seen these rip off prices just for a colour difference. E.G. DX headlamp cowl is £152 in black but if you want an orange one it's £431. Amazing eh!! And there are many more examples just like that.
 

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Discussion Starter · #12 ·
No. Harley parts lists are pretty much std across the board. They list the same 2 part nos in the UK, one for platinum and one for black with a £54 premium for black. It is not the first time I have seen these rip off prices just for a colour difference. E.G. DX headlamp cowl is £152 in black but if you want an orange one it's £431. Amazing eh!! And there are many more examples just like that.
Maybe I will just order the platinum and rob the thermostat and install in mines.
 

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My Last Ride
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It would work but a restrictor would need to be added. Having too much flow , it will actually overheat most times.
Ron
CORRECT !

The coolant has to stay in the engine long enough to become heat soaked. Otherwise the coolant doesn't extract heat from the engine.
 

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CORRECT !

The coolant has to stay in the engine long enough to become heat soaked. Otherwise the coolant doesn't extract heat from the engine.
Can you elaborate on this?

1 gallon of coolant can carry X amount of heat out of the engine, so why does it matter how long that 1 gallon of coolant stays in it? There'll be another cc of coolant incoming. For each gallon (or cc, whatever) leaving the engine, another comes in.

That's why it take a motor without a thermostat a much longer time to heat up, and in the winter it may not get to operating temp, right?
 

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Can you elaborate on this?

1 gallon of coolant can carry X amount of heat out of the engine, so why does it matter how long that 1 gallon of coolant stays in it? There'll be another cc of coolant incoming. For each gallon (or cc, whatever) leaving the engine, another comes in.

That's why it take a motor without a thermostat a much longer time to heat up, and in the winter it may not get to operating temp, right?
Overheating occurs in some engines because the fluid is moving too fast. Some systems have more natural restrictions in play that might prevent overheating but most commonly, fast moving coolant doesn't have enough time to absorb heat from the surfaces it contacts and not spending enough time in the rad to be cooled from the cores. Most common solution is to put a restrictor, usually a washer in place of the thermostat or elsewhere in the hose systyem to slow the fluid the the same rate as a fully open stat would give.
I've not tested this in freezing weather but it should behave the same way.
Ron
 

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Autobanmod
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Overheating occurs in some engines because the fluid is moving too fast. Some systems have more natural restrictions in play that might prevent overheating but most commonly, fast moving coolant doesn't have enough time to absorb heat from the surfaces it contacts and not spending enough time in the rad to be cooled from the cores. Most common solution is to put a restrictor, usually a washer in place of the thermostat or elsewhere in the hose systyem to slow the fluid the the same rate as a fully open stat would give.
I've not tested this in freezing weather but it should behave the same way.
Ron
Sorry but this is nonsense. Heat transfer improves with flowrate.
 

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Sorry but this is nonsense. Heat transfer improves with flowrate.
You are entitled to your opinion, however overheating without restriction in a cooling system to slow the flow has been proven over and over again. An increase in energy transfer occurs with a slower moving fluid. This in effect takes heat from engine and cools better in the rad with better heat exchange to the cores Some engines have more natural restriction then others. I didn't dream this thermal dynamics shit up over night. What I will give you is, not all will overheat.
Ron
 

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You are entitled to your opinion, however overheating without restriction in a cooling system to slow the flow has been proven over and over again. An increase in energy transfer occurs with a slower moving fluid. This in effect takes heat from engine and cools better in the rad with better heat exchange to the cores Some engines have more natural restriction then others. I didn't dream this thermal dynamics shit up over night. What I will give you is, not all will overheat.
Ron
You are only half rite and your backwards, sorry fact not opinion.

You will have greater flux at a higher mass flow rate

Q=mCpdT standard equation used to govern heat flux where:

Q= heat flux
m= mass flow rate
Cp= specific heat capacity of the fluid
dT= temperature difference between point 1 and 2,

As m gets larger so does Q meaning more heat is transfer. also as dT gets larger so does Q. Increase either/or will increase Q.

ill give you this, what you are trying to say is that if the fluid slows down in the radiator, you allow that fluid more residence time in the radiator to equilibrate to the ambient temperature. The temperature of the fluid in the radiator will asymptotically approaches that of the ambient air. This created a larger dT as the fluid is reintroduced to the motor.

As that same cooler fluid enters the motor our good old friend Bernoulli that states that in order for the system to maintain adherence to the first law of thermodynamics, the velocity of the fluid must increase at a lower pressure. So as that coolant goes through those smaller journals bends and restrictions you mention the velocity is sped up. Thus you have what was mentioned earlier; a higher flow rate at a greater temperature differential thus facilitating more energy removal.

The fluid them leaves the motor is recombined into a single stream which again, in order to maintain adherences to the first law, it slows down and pressure increases. This is why you get a slower moving fluid in the radiator.

What you are doing by put a washer in is physically creating a restriction. You are purposefully introduction a frictional losses which results in a lower flow rate and pressure downstream of the restriction. You are purposely wasting energy to get that fluid to slow down, this increasing residence time further in the radiator.
 
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