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I'm not really smart enough to have premises :D But yeah, you definitely can't argue with the facts.


I just found it interesting that Tbob suggests the bike will run 215'ish temps in stock trim with an "old fashioned" 160 tstat. So he added a bypass with a 195 tstat which results in more faster warmups/ consistent temps,but he makes no remarks about the bike actually running any hotter on coolant temps, just up to temp quicker and stays at that temp. It felt to me that he is saying that he saw no higher operating temp than stock, simply just more consistent temps.

Reading that leads me to think:

1: With a stock 160 tstat the coolant temps will typically peak around 215, but fluctuate constantly.
2: A tbob equipped bike will still max out at 215, but it will hold that temp consistently.

Yet, Tbob users seem to say "yeah, the bike runs hotter now, but its more consistent"

Well, if Tbob saw 215 as normal temps ( and made no note of his device causing the bike to run any hotter) , just exactly how hot are these "hotter temps" the Tbob users are reporting? Higher than 215, I must suppose. But just how high? 35 degrees hotter ( for 250 total?...ouch). I dunno...
 

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AFTER the thermostat opens, cooling mechanisms appear essentially identical, Thermo-Bobbed or not.

BEFORE the thermostat opens, I'd expect the coolant in an engine with a 195-degree thermostat to reach a higher temperature than the coolant in an engine with a 160-degree thermostat, but . . . maybe that's just ME! :)

In cooler ambient weather, Thermo-Bob users report consistent temperature gauge readings similar to those seen riding in warmer weather, unlike stock systems where the needle stays on the cooler side of the needle's arc. This phenomenon suggests a higher operating temperature with a Thermo-Bob installed, to me, but I could be in total error.

Regardless, the thermal switch (in the bottom of the radiator) activates the cooling fan at about 205 degrees F. (with or without a Thermo-Bob); the temperature gauge sensor (at the cylinder head) "sees" a different thermal profile.
 

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My KLR's run no hotter after the T-Bob installation. I believe that peak temps are the same, but the bike gets up to temp more quickly and the spikes are greatly lessened.


2 cents,
Dave
 

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I'm not really smart enough to have premises :D But yeah, you definitely can't argue with the facts.


I just found it interesting that Tbob suggests the bike will run 215'ish temps in stock trim with an "old fashioned" 160 tstat. So he added a bypass with a 195 tstat which results in more faster warmups/ consistent temps,but he makes no remarks about the bike actually running any hotter on coolant temps, just up to temp quicker and stays at that temp. It felt to me that he is saying that he saw no higher operating temp than stock, simply just more consistent temps.

Reading that leads me to think:

1: With a stock 160 tstat the coolant temps will typically peak around 215, but fluctuate constantly.
2: A tbob equipped bike will still max out at 215, but it will hold that temp consistently.

Yet, Tbob users seem to say "yeah, the bike runs hotter now, but its more consistent"

Well, if Tbob saw 215 as normal temps ( and made no note of his device causing the bike to run any hotter) , just exactly how hot are these "hotter temps" the Tbob users are reporting? Higher than 215, I must suppose. But just how high? 35 degrees hotter ( for 250 total?...ouch). I dunno...
shinyribs,
Check the OEM thermostat temp of probably All modern gasoline powered cars and trucks. I'll bet you will find None that are under 195f.

The Thermo-Bob does exactly what it was designed to do. Nothing more-Nothing less.
It gets the engines up to Proper Operating temp Quicker and keeps it from dropping Below the 195f set point. Or approximately Mid-point on the gauges, both Gen1 and Gen2. The 210-215 degree semi-normal operating temp of the OEM system is Because of the Cooling Fan temp Switch! This stays the same, with or with-out a T-Bob.
If one speeds up and out-runs the cooling fan on the OEM system, the temp can drop to as little as 160-165f.
With a T-Bob system the temp stays consistently near the 195f optimum because it recirculates thru the warm engine rather than continuing to flow thru the radiator.

(With the Thermo-Bob2 one could use the 160f OEM thermostat. And at least have a little more stable system temps. But I chose to endorse the 195f thermostat usage.)

Maximum engine temperature is dependent upon Radiator Size. Gen1's can hover near the Red Line on 100 degree + days and hard running/climbing. That's 250-260 degrees with pressure cap and 50/50 mix coolant. Gen2 radiators are about 30% larger, which with OEM thermostat exaggerates the over-cool running in <70 degree ambient conditions.
 

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Discussion Starter #25 (Edited)
Regardless, the thermal switch (in the bottom of the radiator) activates the cooling fan at about 205 degrees F. (with or without a Thermo-Bob); the temperature gauge sensor (at the cylinder head) "sees" a different thermal profile.
I think this is an important point to consider. Yes, the higher t-stat temperature would imply a higher peak coolant temp. However, I've read that owners with t-bobs report less fan use. So the engine doesn't appear to approach the same peak temperature as with the stock system.

Since I do a lot of forest trail riding and noticed my fan cycling a lot, I'm inclined to install one to lessen those peak temps. My Mercedes 240D is 100 psi less in compression in the rear cylinder (farthest from water pump) than in the front three (closest). I suspect this stems from when I leaked some coolant and overheated it a few years ago and the cylinder sleeve came out of round. So I'm all for reducing that max temp.

I wasn't aware when I posted, but the t-bob debate seems to be long in the tooth without being settled either way. Soon or later, a new generation of owners come along and re-visit it. Sorry....

Anyway, it seems like a variant of the Ford/Chevy, PC/Mac, 1911/Glock debate. If there's no clear answer, then you're probably safe with either.
 

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If installing a higher-temperature thermostat does not result in a higher engine operating temperature, then the term, "thermostat" is in question: "Thermo," for temperature, "stat," for static.

I've heard tell, in extremely cold environments, some (automobile, truck, etc., operators) replace stock engine thermostats for higher-temperature ones, for the purpose of increasing engine operating temperatures. And, I've heard, engine temperature gauges actually read higher after such modification.

I have no Thermo-Bob installed. In my experience, my Generation 1 temperature gauge reads lower when riding in cold weather than on a hot day. My 70,000-mile '08-riding partner (who LOVES his Thermo-Bob!) says his temperature gauge reads about the same, regardless of ambient conditions.

Thus, on a cold day, I'd conclude his Thermo-Bobbed engine's operating at a higher temperature than mine, a condition attributable at least to some extent to a 35-degree higher thermostat.

I've thought a higher-temperature thermostat results in a higher engine operating temperature, but . . . if I'm wrong, that's not the FIRST false concept I've ever harbored! :)
 

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I wasn't aware when I posted, but the t-bob debate seems to be long in the tooth without being settled either way. Soon or later, a new generation of owners come along and re-visit it. Sorry....

Anyway, it seems like a variant of the Ford/Chevy, PC/Mac, 1911/Glock debate. If there's no clear answer, then you're probably safe with either.

I'm not aware that there IS a debate.

- A thermobob does NOT increase overall cooling capacity nor does it decrease maximum temperatures. What it does is increase minimum temperatures, decrease temp swings and minimize the delta T in the engine.
....all this is pretty much universally agreed amongst those in the know to be good things.....HOW good or how much longer an engine would last with a T bob vs. without; THOSE things are impossible to quantify and is the only real source of any debate AFAIK.

Short answers:

- will a Thermobob cure my overheating issue? No

- will a Thermobob benefit my engine? Yes

- Do I NEED a Thermobob? ....here you'll get some differing opinions. I actually say NO, you don't NEED one....but it is a good thing and you're engine will thank you for it. I have T Bob's on both my KLR's.


2 cents,
Dave
 

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I'm fully aware that a Tbob doesnt produce cooler temps. I'm also fully aware that there was no claim to this from the Tbob literature. I said that plainly in my last post.

I'm also fully aware that many modern vehicles use much higher temp tsats than some of the older carbureted vehicles. However, I don't know what the hell that could have to do with any of this.

I do also know that if you Google around, reading about the Tbob that you will find many users who claim they now see their bike running a higher overall temperature compared to stock. That's not a thesis or a theory or test of my own, nor did i every imply that Tbob will do this( exactly the opposite, actually), but I just shared the point of view being shared online.


Here, I'll break it down as simple as possible.

Tbob claims the stock cooling system fluctuates too much, so he made a device. Testing proves that his device cures the fluctuations with no increase of actual operating temps. Sweet! However, Tbob users are claiming higher overall temps after installing the device.

Huh, interesting, no? Initial tests don't reflect these higher temps, but extended use seems to suggest that many users are actually seeing this.

So my thoughts were: "Huh, that's interesting. I wonder exactly how hot they are getting?"
 

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Or it just means there's not enough heat in the water to trigger the sensor that's mounted on the radiator, because the Tbob is just circulating the hot water back through the engine vs pushing it up to the radiator to be cooled.


Run a KLR dry. Will it overheat? Yup. Will the gauge read over-temp? Nope. Because there won't be water available for the gauge to measure. Gauges can be tricky things if all is not in order
 

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Or it just means there's not enough heat in the water to trigger the sensor that's mounted on the radiator, because the Tbob is just circulating the hot water back through the engine vs pushing it up to the radiator to be cooled.
Fascinating theory, shinyribs, but . . . not one promulgated by Watt-Man, AFAIK.

If a Thermo-Bob and its + 35 degree F. delta thermostat make an engine run cooler, so be it.

Run a KLR dry. Will it overheat? Yup. Will the gauge read over-temp? Nope. Because there won't be water available for the gauge to measure.
The temperature gauge measures electrical resistance; no water necessary for that.

Running an engine dry to overheating, you probably WOULD see an indication on the temperature gauge, I think, because . . . the heat sensor in the cylinder head area is resistive, connected electrically (not hydraulically) to the temperature gauge; the resistance of the sensor should change inversely with the conducted heat temperature from the engine castings, I would think . . .

But . . . maybe not!
 

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I'm fully aware that a Tbob doesnt produce cooler temps. I'm also fully aware that there was no claim to this from the Tbob literature. I said that plainly in my last post.

I'm also fully aware that many modern vehicles use much higher temp tsats than some of the older carbureted vehicles. However, I don't know what the hell that could have to do with any of this.

I do also know that if you Google around, reading about the Tbob that you will find many users who claim they now see their bike running a higher overall temperature compared to stock. That's not a thesis or a theory or test of my own, nor did i every imply that Tbob will do this( exactly the opposite, actually), but I just shared the point of view being shared online.


Here, I'll break it down as simple as possible.

Tbob claims the stock cooling system fluctuates too much, so he made a device. Testing proves that his device cures the fluctuations with no increase of actual operating temps. Sweet! However, Tbob users are claiming higher overall temps after installing the device.

Huh, interesting, no? Initial tests don't reflect these higher temps, but extended use seems to suggest that many users are actually seeing this.

So my thoughts were: "Huh, that's interesting. I wonder exactly how hot they are getting?"

Relax. I'm glad you're fully aware....it didn't appear so when you mentioned a debate as to the usefulness of a Thermobob. I frequent 4 different KLR Forums and groups and have for a decade or so and after sifting through hundreds of posts on the subject, I don't believe there is a "debate" on the subject. That is all.

To be clear; if you are referencing the thread on .net, that guy has other issues going on and despite the ease of removing the T bob to PROVE that it is (or isn't) causing the issue, he's yet to do that.

There may well be other people out there claiming that the T bob increases max temperatures but I haven't seen a statistically significant number of people claiming so.

Just trying to help,

Cheers,
Dave
 

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O/K my 2 cents worth on the thermobob before I installed one on my 2010 I would watch the temp gauge move like a porch swing now with the bob it holds steady in the middle telling me the engine temp does not fluctuate as much holding a more constant temp. When the thermostat without the thermobob bypass, cooler coolant is dumped on a hot engine until it equals temp then heats up repeating the cycle over again. Hot it will expand and cool it will contract continually with each cycle of the thermostat opening and closing. Could this cause a thermo shock, work harden, fatigue the metal ? I don't know but watching that gauge stay steady in the middle gives me comfort
 

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Fascinating theory, shinyribs, but . . . not one promulgated by Watt-Man, AFAIK.
OK. And? Did anyone say he did?

It's not really that fascinating, either. Especially considering we are talking about a system specifically designed to circulate water away from the cooling system.

Regardless, I just had simple ( I thought ) questions, but I'm not really up for having to proof read every word I type with extreme scrutiny. Communication can take place just fine without the need to pick apart others nomenclature.

I'ma go back to the shed and play with the scoot :) Y'all have fun.
 

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OK. So I figured I'd jump into the pool. The thing I don't understand about the thermobob is why the KLR is different from every other liquid cooled motorcycle I've ridden over the past 20 years. Just to name more recent rides, like my ZX6R or CB1000R for example, all ran at a low temperature. Then the temperature would sky rocket at a stop light and eventually the fan would kick on. If I remember correctly the ZX6R would run around 168 or so and the fan kicked on at 217. And you would literally see the temperature raise 40 or even 50 degrees at a stop light here in Florida. If I remember, every bike I've ever ridden with a temperature gauge did this. Now I will say that when I switched to Redline 20w50 in the KLR, it slowed the temperature change down a bit. It seems to cruise at a slightly higher temp and reach a slightly lower temp at a stop light, all while taking longer to change. The 10w40 had the needle bouncing more rapidly, but still not any more than other liquid cooled bikes I've ridden. And none of my rides other than a 95' Magna, ever developed a leak (Excluding Harleys).
 

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It's not really that fascinating, either. Especially considering we are talking about a system specifically designed to circulate water away from the cooling system.
Here's what Watt-Man himself says about increased engine operating temperature with Thermo-Bob installed:
I fixed the "too cold" problem by designing and installing a
hotter thermostat and added a bypass to the system, as most liquid-cooled engines are designed with one from the factory. Now I have more stable and warmer coolant, plus hotter oil which should result in longer engine life.... and a slight increase in fuel mileage as well.
Quotation from this link:

http://www.watt-man.com/uploads/TB_Testing.pdf

On Page 4 of the text from the link, the chart, "Comparison of Average Temperatures of Water Within Engine," shows coolant running 40-45 degrees higher with the Thermo-Bob than with the stock system.

On Page 5, the chart, "Oil Temp Comparison," shows oil about 15 degrees F. hotter with the Thermo-Bob, compared to the stock system.

Thus, seems to me, the developer of the Thermo-Bob himself (Watt-Man), suggests the KLR650 engine runs at a higher engine operating temperature with a Thermo-Bob installed. YMMV!
 

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Here's what Watt-Man himself says about increased engine operating temperature with Thermo-Bob installed: Quotation from this link:

http://www.watt-man.com/uploads/TB_Testing.pdf

On Page 4 of the text from the link, the chart, "Comparison of Average Temperatures of Water Within Engine," shows coolant running 40-45 degrees higher with the Thermo-Bob than with the stock system.

On Page 5, the chart, "Oil Temp Comparison," shows oil about 15 degrees F. hotter with the Thermo-Bob, compared to the stock system.

Thus, seems to me, the developer of the Thermo-Bob himself (Watt-Man), suggests the KLR650 engine runs at a higher engine operating temperature with a Thermo-Bob installed. YMMV!
You're absolutely right, except for one thing; The Thermobob makes the engine run hotter at normal engine operating conditions (Wattman says "average temps have been raised" but it doesn't raise the MAXIMUM temperature the engine will reach. Once the thermostat opens, the temp of the thermostat becomes irrelevant.

Cheers,
Dave
 

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You're absolutely right, except for one thing; The Thermobob makes the engine run hotter at normal engine operating conditions (Wattman says "average temps have been raised" but it doesn't raise the MAXIMUM temperature the engine will reach. Once the thermostat opens, the temp of the thermostat becomes irrelevant.

Cheers,
Dave
As mentioned previously (several times, I think), after the thermostat opens, the engine is at the mercy of coolant circulation and radiator air flow, Thermo-Bob or not.

I never said the Thermo-Bob raised any MAXIMUM temperature; on the contrary, I said nominal engine operating temperature was higher with a Thermo-Bob, a concept I think corroborated by Watt-Man's website comments and test data graphs.

The, "maximum temperature," I suppose, is the boiling point under radiator cap pressure of the coolant, a parameter unaffected by the presence or absence of a Thermo-Bob.
 

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As mentioned previously (several times, I think), after the thermostat opens, the engine is at the mercy of coolant circulation and radiator air flow, Thermo-Bob or not.

I never said the Thermo-Bob raised any MAXIMUM temperature; on the contrary, I said nominal engine operating temperature was higher with a Thermo-Bob, a concept I think corroborated by Watt-Man's website comments and test data graphs.

The, "maximum temperature," I suppose, is the boiling point under radiator cap pressure of the coolant, a parameter unaffected by the presence or absence of a Thermo-Bob.

We're good, I just want anyone else reading this to be clear that the maximum temps aren't affected by the T-Bob, in other words your bike isn't going to overheat due to installing one......several statements made in this thread could be taken the wrong way.....or I'm easily confused.....or both. :grin2:

Cheers,
Dave
 
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