Thermostat choice

[Mase]

I am going to pull the carb bank and replace it with a spare rebuild I have this winter.  Any advantages to going with a cooler rated thermostat than stock?

Mase

[sandy]

Keep it stock. Fuel economy and HP can be affected negatively.

[John Schmidt]

When I added the I/S pods and the plastic thingy behind the fan, my Tourer started running hotter. Prior to that, it never went high enough for the fan to come on except in temps in the high 90's and stop and go traffic. After the additions, it was on/off all the time and running hotter even at highway speeds(I have gauges for everything). So, before my summer trip this year, I changed the t'stat from the stock temp down to 160-165(forget exact figure). Now, in the heat of summer the fan comes on about like before....only periodically in stop/go traffic. At speed in the summer, it will run between 180 & 190 at the very most, depending on how hard I'm pushing it(most of the time more like 175/180). As for mileage, it wasn't affected in the least, still got in the mid 30's with a good load on. Highway mileage is slightly less the last couple years since I added the pods and a fairing, dropped 2mpg at the most, running around 70 or a bit higher.

[Robert]

I agree with John and its alot friendlier on the legs and body when its 98 and Humid.

[98valk]

as long as the oil temp gets to at least 200F and water temp at 180F then for your local climate the engine will not see excessive wear.

[John Schmidt]

Bought it at Advance Auto Parts, along with the gasket. The 160 deg. t-stat is p/n 143-0687, made by Beck Arnley, perfect replacement except it's 160 deg. instead of 180. The gasket needed is Fel-Pro #25565, for a Volvo. I replaced it by pulling the radiator and letting it hang forward. You need to release the wire clips on the back so it doesn't break the wiring, I just tie it up and let it hang....after draining the coolant naturally.    You can then get to the three bolts that hold the t-stat in place, the one in back is tricky but can be done.

[98valk]

as long as the oil temp gets to at least 200F and water temp at 180F then for your local climate the engine will not see excessive wear.

Interesting quote.  Can you elaborate more?

engine wear increases when lower than those numbers. some websites on oil have indicated that some additives in oil need at least 200F to function correctly.

I have ridden down to 25F and the water temp does not get above 150F unless I block the rad. Around 40F I run with 95% of the rad blocked. This will give me close to 190F after a 13-15 mile ride. oil temp will get to 190-200F

[Robert]

CA I know that you are pretty technical but to put this is perspective your engine will not fall apart if you have a lower operating temp. Every day I have a short commute to work the engine never really warms up and yet my engine is not showing any significant wear. According to the temp gurus my engine should be a pile of worn metal shavings by now. I do also have a cooler thermostat so that when I go for rides it will get to temp. So there may be increased wear but there is increased wear from hard acceleration not changing the oil frequently enough and so many other things that it really all averages out to a pretty long life. I am personally pretty anal when it comes to maintenance but there comes a point that you have to just ride and not worry. If when I work on cars had listened to all the so called experts and all the tests I would have either gone out of my mind, closed the buisness or not gotten anything done. So I'm just saying I have found most mechanical things to be pretty tough and if we do the best we can then we make the percentages go up but in any case it will survive to a high mileage.

[Tx Bohemian]

... I added the I/S pods and the plastic thingy behind the fan, my Tourer started running hotter...

This is interesting to me as I just added  "Bohemian rigged" pods to deflect the air coming through the radiator away from me. (long story, but they work)

 I got a couple of questions:

The factory thermostat is 180 and John you went to a 160, is there anything in between? like maybe a 170?

And where is there a good place to get a radiator cap for these bikes besides the $35 one at the dealer?

[Don in SC]

The one reason not discussed about going to a lower thermostat is the fact that for ever gallon of gas burned while an engine is warming up you create a gallon of water in the crankcase! This is if you have 50%+ humidity. You have to warm you oil up enough to evaporate the water out of your oil so the Crank case vent- PCV valve can pull it out. If you make short trips you build water in the oil.   

[Robert]

The one reason not discussed about going to a lower thermostat is the fact that for ever gallon of gas burned while an engine is warming up you create a gallon of water in the crankcase! This is if you have 50%+ humidity. You have to warm you oil up enough to evaporate the water out of your oil so the Crank case vent- PCV valve can pull it out. If you make short trips you build water in the oil.   

Well your almost right the gallon of water goes out the exhaust not in the crankcase. A Certain portion does but not that much. Also the oil will usually get hot enough with a cooler thermostat to remove the water. There is not usually a direct correlation from coolant temp to oil temp.

[Jeff K]

I bought the generic #143-0687 thermostat, yes it fits, but, the coolant port is considerably smaller. About .160 smaller in diameter. So I went on the hunt for a high flow that fits. The Motorad 2040-180 is a high flow but I can't find it on the shelf anywhere. And I really want to put a 160 in it anyway.
The 2040-180 high flow crosses over to a 15868 Duralast at Autozone, but they don't have a high flow in 160 degree listed.

Still looking though.

[98valk]

I bought the generic #143-0687 thermostat, yes it fits, but, the coolant port is considerably smaller. About .160 smaller in diameter. So I went on the hunt for a high flow that fits. The Motorad 2040-180 is a high flow but I can't find it on the shelf anywhere. And I really want to put a 160 in it anyway.
The 2040-180 high flow crosses over to a 15868 Duralast at Autozone, but they don't have a high flow in 160 degree listed.

Still look though.

OEM unit is high flow.
It begins to open at 176-183, fully open at 203. With my water temp gauge mine opens right about 178-180F
most T-stats are fully open 20F past their rating.
a t-stat has no relation to what temp your engine runs at, once the T-stat is open it is a function of ambient air temp, radiator efficiency, fan speed etc.
in other words if the engine wants to run at 195F on a warm day it will still do it with a 160 t-stat, it just will take a little longer to get there, but it won't stop it.

Is 16F opening difference really going to help?

GL1800 T-stat is 169-176, fully open at 194. its flow direction is different, reason for lower #s. don't know if it fits the Valkyrie.
Good luck.

[Chrisj CMA]

I didnt think the carbs had to come off to change the thermostat.  You should be able to access it by just removing the radiator yes?

[Jeff K]

I didnt think the carbs had to come off to change the thermostat.  You should be able to access it by just removing the radiator yes?

yes, just pull the radiator.

Well, unless you are me...
Pull the radiator
Pull the Tank
Pull the TB
Pull the injector manifolds
Pull the blower
Pull the blower tubes
Pull the blower manifold

Crappy job for a look see.

[98valk]

I didnt think the carbs had to come off to change the thermostat.  You should be able to access it by just removing the radiator yes?

yes, just pull the radiator.

Well, unless you are me...
Pull the radiator
Pull the Tank
Pull the TB
Pull the injector manifolds
Pull the blower
Pull the blower tubes
Pill the blower manifold

Crappy job for a look see.

sounds like it be easier to just drop the engine.

[Jeff K]

The verdict is in for me. The Duralast 15868 is the way to go for a replacement thermostat. It has the same size port, and opens much farther than my stock unit, though my stock unit has been used.
It's a 180 degree. It's supposed to have 50% more flow than the stock 143-0687 unit.

[98valk]

CA I know that you are pretty technical but to put this is perspective your engine will not fall apart if you have a lower operating temp. Every day I have a short commute to work the engine never really warms up and yet my engine is not showing any significant wear. According to the temp gurus my engine should be a pile of worn metal shavings by now. I do also have a cooler thermostat so that when I go for rides it will get to temp. So there may be increased wear but there is increased wear from hard acceleration not changing the oil frequently enough and so many other things that it really all averages out to a pretty long life. I am personally pretty anal when it comes to maintenance but there comes a point that you have to just ride and not worry. If when I work on cars had listened to all the so called experts and all the tests I would have either gone out of my mind, closed the buisness or not gotten anything done. So I'm just saying I have found most mechanical things to be pretty tough and if we do the best we can then we make the percentages go up but in any case it will survive to a high mileage.

http://www.gi.alaska.edu/ScienceForum/ASF7/747.html

http://www.irday.com/html/Engine%20fuel%20engineering/20080412/8400.html
Ref: SAE J300 Dec95

More wear at temps less than 180 has to do with quenching of the F/A ratio and washing of the oil film from the cylinder wall, also dilution of the oil with both fuel and with condensation from moisture from combustion byproducts blown by the rings.  This leads to production of corrosives and corrosive erosion which a micrometer would measure as material loss/wear.

My point is that I want the same cylinder pressure at 200k+ miles as was there at 1k miles.
Using the correct oil and the engine is at proper op temp will prevent increased wear during hard acceleration.