Dealing With The Heat

[gringo88]

Not a good idea to remove the thermostat from your cooling system. Your fuel injection system delivers fuel ratios depending on your engine temperature. If it ran cooler, it would feed a rich fuel ratio continually. Not good
Also, your combustion needs to burn clean and be fuel efficient and it only does that when your engine is at the predetermined temperature it was designed for. That's what the thermostat does. It's a very important part of your engines design.

+1 on this. This is why you put a ThermoBob on a KLR650; get the temp up asap and then stabilize at peak operating temp. The bikes run as designed, it's the pilots that need to to recalibrate their resistance to the heat thrown off. Camelbak and Gatorade!

 

[Larry Fine]

Maybe a silly idea... but... what about removing the thermostat, unless you know you will be driving in freezing temperature ?

I'm sure the flow of the coolant will be improved.

Others have disagreed with me on this, but stuff on automotive engineering I have read has mentioned this.

While the flow would definitely be at maximum without a T-stat, that doesn't mean maximum engine cooling will be obtained. The coolant must remain in contact with the internal engine surfaces long enough for heat to be transferred to it, as well as in the radiator passages long enough for that heat to be removed from it.

Think about the T-stat's location in the cooling system. The only thing it has contact with is the coolant attempting to leave the engine. By making sure the coolant is hot before it's allowed to leave, it has assured that it has absorbed heat. If allowed to flow freely, the engine itself could theoretically over-heat as well as over-cool.

Added: In other words, the coolant could be circulating through the system as fast as the pump can push it, while the engine's internal parts slowly get hotter. This may not really make itself known until the engine is turned off and the extra-hot engine is now transferring heat to the stationary coolant, turning it to steam.

Depending on ambient temperature, engine and cooling system characteristics, operating conditions, etc., a T-stat could very well be gradually opening and closing during operation, thereby modulating the coolant flow in an attempt to maintain engine temperature within a given design range, or what we call "normal" operation.

 

[Kevcules]

+1 on this. This is why you put a ThermoBob on a KLR650; get the temp up asap and then stabilize at peak operating temp. The bikes run as designed, it's the pilots that need to to recalibrate their resistance to the heat thrown off. Camelbak and Gatorade!

Funny you mentioned the thermo bob. I installed one of those on my 04 KLR 650 about 10 years ago and “ Wattman” said I was one of the first ones to buy from him. Well made unit from a very intelligent man.

 

[MikeC]

Gents;
My theory is that as long as the cooling system can handle it, we are okay. 'Fan on, fan off'. The stat will slow down the coolant flow so that it has time to absorb the engine's heat, if the coolant flows too fast the engine will actually run hotter.
Mike Coleman
North Lancaster
Ontario, Canada.

 

[ChriSTian_64]

OK....
So it was really a silly idea, then.

 

[Al Gully]

Not a good idea to remove the thermostat from your cooling system.

Great write up Kevin, my 2nd ST1300 that I picked up on May 1st of this year has a stuck open thermostat.
So in May terrible gas mileage do to it taking 10 miles to hit 3 bars.
June comes around and the fuel mileage improves, but still terrible as it takes 5 miles to warm up.
Now in July with temperatures up to 95 F today, fuel mileage is off the charts and it's the best mileage I've ever seen between my ST1300 I bought in 2009 and my new to me one.
Morel of the story, the thermostat is an important part of the fuel delivery system.
The good news is, the new thermostat and gasket is sitting on the surgery table waiting for a down time.
May happen in Dec of this year.

 

[Al st1100]

Others have disagreed with me on this, but stuff on automotive engineering I have read has mentioned this.



Think about the T-stat's location in the cooling system. The only thing it has contact with is the coolant attempting to leave the engine. By making sure the coolant is hot before it's allowed to leave, it has assured that it has absorbed heat. If allowed to flow freely, the engine itself could theoretically over-heat as well as over-cool.

not, The coolant in the engine block and heads is constantly circulating. The water pump moves a lot of coolant around. Lower parts of the engine block does not get generate as much heat as the cylinder heads. Therefore your theory of the coolant not moving to absorb heat is incorrect.

 

[Andrew Shadow]

not, The coolant in the engine block and heads is constantly circulating. The water pump moves a lot of coolant around. Lower parts of the engine block does not get generate as much heat as the cylinder heads. Therefore your theory of the coolant not moving to absorb heat is incorrect.

The coolant always circulates, but not through the radiator. The coolant continues to absorb heat while it circulates within the engine until the thermostat opens and exposes it to the radiator where it gets cooled.

Remove the thermostat and you will be experiencing an overheated engine.

 

[Kevcules]

I’ve never seen or experienced overheating with a stuck open thermostat but rather not reaching operating temperature. Removing one would simulate the same situation I believe

 

[CruSTy]

I’ve never seen or experienced overheating with a stuck open thermostat but rather not reaching operating temperature. Removing one would simulate the same situation I believe

The guy in this video is wrong. Removing the thermostat can cause overheating and here is why. The water pump is a centrifugal pump operating in a closed loop system. Centrifugal pumps require a larger inlet than outlet to maintain some back pressure on the impeller. If the outlet is unrestricted the impeller will cavitate and not pump the fluid. I have experienced this first hand. When The thermostat is open it is still functioning as a restrictor plate to insure the pump outlet is smaller than the inlet and prevent cavitation. Do not run without a thermostat!

 

[ChriSTian_64]

Very interesting.

 

[W0QNX]

You get used to it. We have 4 to 6 months a year of the sticky stuff. I've been riding quite a bit in the mornings lately just to beat the 10am showers and almost everyday the last week was 87 degrees by 9 am.

Note the "Feels like" below. And it's dry and no rain expected today. No it's not 105 but it's also not a dry heat. My only secret is mesh gear.


Pensacola, FL Weather
Local Info

Current Conditions at 9:58 AM CDT 90°F 32°C Feels Like 107°F Humidity 72% Solar Rad 255 w/m2 Dew Point 79°F UV Index 2 Wind E 2 MPH Gusts 2 Barometer 30.22 in. 767.6 mm - Steady Report from 0.8 miles ENE of central Pensacola

 

[red one]

Yep. Planning to do my monthly 180 mile RTE next Tuesday. Forecast is for 92 degrees and High humidity. But yeah sometimes you got to grin and bear it. Remember that back in the 1850's people use to ride in these temperatures on horseback and cross-country trips in covered wagons. So quit complaining

 

[dtcoleman]

Hey Uncle Phil.
You know very well us folks here in Southwestrn Ontario it gets pretty humid. You know the saying " it's not the heat it's the humidity". I'm a ATGAT guy pretty much unless it's going downtown or a short ride to the beach so armored jeans not my usual riding pants (vented). With the possibility of late in the day thunder storms there's no way I wear mesh. You'll just become a soggy drowned rider. My regular jacket vents however hydration is important on hot days in the south where you live. Regular stops to rehydrate and revitalize like every 2 hours or less if important. A good night's sleep the night before is also important so not to pass out on that long ride.
I belive Dean uses a cooling scarf around his neck and a head bandana to wick aware sweat. I think Lyle has a Camel Back hydration system but you do have get rid of the excess.

Looking forward to seeing you in September. Hopefully the gremlins will stay home and not bother us. Not sure if you heard but my auxilary lights came lose on the TCH? On the way back I had a front brake caliper sticking. It seized up arriving at my sisters place in NB. It seemed fine later and pulling out the next day but it started to seize up again. Got it fixed in town before hitting the TCH. A good Samaritan stopped to help. An old truck driver so we had a conversation. He had a pry bar and penetrating oil and we performed a road brake service.
I was going to take the bike to work the other day and it was dead. Jumped the battery with the power pack and the Black Knight started. I think I need a battery. Going to get it checked out today at Canadian Tire. Fingers crossed they have one the same Amp hour rating and size.
Stay safe. Be well.
Dave

 

[Erdoc48]

I finally was able to get out on the bike this AM after a couple of weeks of no riding (actually the Silverwing as I was trying out a new windshield on it)- it’s been pretty hot and humid in SC- here, cooling vests (the evaporative kind) just don’t work as humidity is > 80% and sometimes up to 100%. Not bad at all when I left, but I made sure I was gone by 7AM and was back by 11 or so. The past few days have been very humid, even if not hot (like above 90 degrees)- I’ve been walking the pups around 6-6:15 AM in the past few days, and the air just feels thick, even if it’s not sun up yet. Some days have been ~ 80 degrees even overnight. Nice thing about SC is that you can ride year round if you can stand the summer heat and humidity and if not, the best riding weather is yet to come (like in mid to late September and onward). I ride frequently even in the winter here, just throw on heated gear (and even that is used pretty infrequently).

 

[Uncle Phil]

In Tennessee, July and August are probably the worse - the high humidity and high temps.
When I get up to do my morning walk at 4 AM and it's already hot and humid before the sun comes up good, you know it's gonna be tough!
I still ride to work as it is only 10+ miles one way so all my 'ladies' get some exercise.

 

[Al st1100]

The guy in this video is wrong. Removing the thermostat can cause overheating and here is why. The water pump is a centrifugal pump operating in a closed loop system. Centrifugal pumps require a larger inlet than outlet to maintain some back pressure on the impeller. If the outlet is unrestricted the impeller will cavitate and not pump the fluid. I have experienced this first hand. When The thermostat is open it is still functioning as a restrictor plate to insure the pump outlet is smaller than the inlet and prevent cavitation. Do not run without a thermostat!

First the water pump pumps coolant thru many small passages before it get to the T'stat. Did you ever see a head gasket The big round holes are for head bolts, very small holes are for coolant. So there is enough restriction that would satisfy your restriction theory with out the need for a t'stat. And finally look how the coolant flow is routed. Why your vehicle overheated without a t'stat I can only speculate but if everything else in the system was normal it should not have overheated.

 

[oude geit]

The coolant needs the dwell time in the radiator to expel heat. Without a stat this dwell time doesn't occur. The system is balanced for flow rates, ambient temp, heat load and exchange rates.

 

[ChriSTian_64]

It may have been a silly question, but I'm so glad I've asked it.
Answers are very instructives. I'm learning new things about the cooling system.

The coolant always circulates, but not [always] through the radiator.

Ah! That must explains why there is a by-pass hose, on the ST1100, from the thermostat housing ( after the coolant went thru the engine, but before it goes thru the thermostat), and brings the coolant back to the base of the cylinders, where the coolant coming from the bottom of the radiator enters the engine. So, some coolant could by-pass the thermostat and radiator and keep circulating thru the engine.

Sorry @Uncle Phil , I don't want to hijack your thread with another subject. I was thinking at a way to keep the engine a bit cooler in those extreme record heat, and that it might also help the rider if the engine is a bit cooler.

 

[ST1100Y]

May this help: