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Discussion Starter #1
I apologize in advance because I'm sure this is answered somewhere but I couldn't find it...my 2011 KLR 650 with 9,800 miles on it seems to get really warm or even hot when I'm sitting at a light or stopped for a few minutes.
After I bought it, April 2019, I had the radiator flushed and put in Engine Ice.
Coolant level is good and when I'm moving the temp is good.
Is this normal and I'm worried about nothing?
Thanks for you advice,
Frank
 

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It is Not Too hot unless the needle on the gauge is touching the Red Zone.

1/2 to 5/8th scale would be normal in traffic or off-road trail riding, this the temp range that the fan should come on. 3/4 scale could be Normal on a Hot Summer day, even on a Gen 2.

We really need more complete info from you.
 

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Normal.

Electric cooling fan should kick in when the coolant reaches around 200 degrees F.; functional fan (and thermal switch) will cool engine down via coolant to safe temperatures.

Assuming reasonable calibration of your temperature gauge, anything under far-right red indicates safe temperature, as pdwestman posts above.
 

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Discussion Starter #5
Gentlemen,
Thank you very much for the insight.
I always look to the experts for advice, even when I'm not a rookie (in this case I am).
Do you feel like Engine Ice is the best coolant?
Also, my KLR has not had the ThermoBob installed. It sounds like that is critical, do you agree?
Thanks again,
Frank
 

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The Thermo-Bob actually causes a HIGHER nominal operating temperature than a stock cooling system (has a higher thermostat threshold).

Otherwise, advantages are assumed/presumed from stabilizing coolant temperature more fully, and for operating at a higher design goal temperature.

Critical? Your call! You might consider, among the thousands of KLR650s manufactured and marketed worldwide over 25 years plus of production, what percentage have a Thermo-Bob installed.

Also, the environmental climate of operation plays a role--Thermo-Bob value probably greater in colder weather (faster warm-up).

The Thermo-Bob is soundly designed, conscientiously manufactured, and responsibly marketed, AFAIK. Still, your choice!
 

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Discussion Starter #7
Very helpful, thanks.
It sounds like living in the South I may not need to worry about the ThermoBob.
I just need to verify that my fan is coming on as needed.
Thanks very much Damocles, and get out from under that sword.
Frank
 

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I would slightly disagree with Damocles on a couple of points;

- the Thermobob only causes a higher MINIMUM operating temperature; it has no real effect on the maximum temperatures the engine will see. From Bill himself: " Bottom Line – This hasn’t raised peak temps at all – but have raised minimum temps when you're
riding and it's below 80F outside. Even here in the desert, that's the majority of my year. In a lot of places,
that's the entire year. "

- as per the above, the Thermobob has a benefit regardless of climate. While higher minimum oil temps are a good thing, I'd suggest that greatly reducing the delta T between incoming and outgoing coolant ("cold shocking" the cylinder) is the greatest benefit.

lastly, while there are thousands of KLR's running and living their lives with the stock cooling system (i.e no coolant bypass, aka Thermobob), and the argument can certainly be made that one isn't strictly NECESSARY, there is little doubt that it can only help and will undoubtably increase longevity.....how much? impossible to quantify and it would vary on an individual case basis anyhow.

Dave
 

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No disagreement, DPelletier--any conflict appears to me to be regarding definition of terms: Specifically, what does, "critical" mean, in the context of the Thermo-Bob installation?

Further, I said the Therm-Bob raised the NOMINAL coolant operating temperature. Since the stock thermostat opens at a temperature lower than the Thermo-Bob's, I think the modified cooling system would operate at a higher nominal temperature. I'd question the term, "minimum," because . . . unless the thermostat is open, seems like to me the coolant temperature remains below that of the thermostat thresholds. If "operating temperature" occurs only when the thermostat opens, then . . . minimum operating temperature might be more appropriate terminology. I think KLR650 engines operate for considerable time during their service lives with thermostats closed, but I have no supporting evidence of the concept and could be in abject error.

You make the correct (but to some, controversial) comment regarding the Thermo-Bob's lack of influence on maximum coolant temperatures: After the thermostats open, stock or Thermo-Bob, either engine configuration's coolant temperature is at the total mercy of water pump circulation and air flow.

"Cold shock" remains an interesting concept; I've wondered at the failure mechanism and the components affected from the phenomenon; same for "heat cycling," reduced by the Thermo-Bob's greater temperature stability than that of the stock system.

Then . . . some believe the absence of a Thermo-Bob causes cylinder bore distortion ("ovalization"), with consequent ring failure and excessive oil consumption.

I think the Thermo-Bob appears consistent with physicians' Hippocratic Oath, "First, do no harm." Critical? Each rider alone determines whether the modification is "critical," to himself.

DISCLAIMER: My riding partner, 95,000 miles on his '08, LOVES his Thermo-Bob!

---------------------------------------------------

Peripheral thought: Does the disappearance of the KLR from the market affect Thermo-Bob sales numbers? Will the Kawasaki successor (if any) to the KLR650 have a modern coolant bypass cooling system (as now offered by the aftermarket Thermo-Bob)?
 

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Gentlemen,
Thank you very much for the insight.
I always look to the experts for advice, even when I'm not a rookie (in this case I am).
Do you feel like Engine Ice is the best coolant?
Also, my KLR has not had the ThermoBob installed. It sounds like that is critical, do you agree?
Thanks again,
Frank
I'll only say to Be Careful as to which Engine Ice product that one uses in which kind of climate.

The Original Engine Ice Coolant had ZERO Anti-Freeze properties!
Thin cast aluminum can be froze broken at a mere 31.9 F degrees if it is cold Long Enough.
 

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No disagreement, DPelletier--any conflict appears to me to be regarding definition of terms: Specifically, what does, "critical" mean, in the context of the Thermo-Bob installation?

Further, I said the Therm-Bob raised the NOMINAL coolant operating temperature. Since the stock thermostat opens at a temperature lower than the Thermo-Bob's, I think the modified cooling system would operate at a higher nominal temperature. I'd question the term, "minimum," because . . . unless the thermostat is open, seems like to me the coolant temperature remains below that of the thermostat thresholds. If "operating temperature" occurs only when the thermostat opens, then . . . minimum operating temperature might be more appropriate terminology. I think KLR650 engines operate for considerable time during their service lives with thermostats closed, but I have no supporting evidence of the concept and could be in abject error.

You make the correct (but to some, controversial) comment regarding the Thermo-Bob's lack of influence on maximum coolant temperatures: After the thermostats open, stock or Thermo-Bob, either engine configuration's coolant temperature is at the total mercy of water pump circulation and air flow.

"Cold shock" remains an interesting concept; I've wondered at the failure mechanism and the components affected from the phenomenon; same for "heat cycling," reduced by the Thermo-Bob's greater temperature stability than that of the stock system.

Then . . . some believe the absence of a Thermo-Bob causes cylinder bore distortion ("ovalization"), with consequent ring failure and excessive oil consumption.

I think the Thermo-Bob appears consistent with physicians' Hippocratic Oath, "First, do no harm." Critical? Each rider alone determines whether the modification is "critical," to himself.

DISCLAIMER: My riding partner, 95,000 miles on his '08, LOVES his Thermo-Bob!

---------------------------------------------------

Peripheral thought: Does the disappearance of the KLR from the market affect Thermo-Bob sales numbers? Will the Kawasaki successor (if any) to the KLR650 have a modern coolant bypass cooling system (as now offered by the aftermarket Thermo-Bob)?

Agreed; we are on the same page.....just wanted to clarify for others that may have misinterpreted your post to imply that the T bob raises the highest temps the engine sees.

I don't believe the absence of a Thermobob is the cause of bore distortion, rather that using one may mitigate the distortion. As far as critical goes; the only mod I would consider "critical" is the doo replacement on a Gen1.....the rest are optional depending on wants, needs, expectations, usage and budget.

As to your peripheral musings; time will tell but since the Versys is also not equipped with a bypass system, whatever "Gen3" KLR comes out may not have one either....

cheers,
Dave
 

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I don't believe the absence of a Thermobob is the cause of bore distortion, rather that using one may mitigate the distortion. As far as critical goes, the only mod I would consider "critical" is the doo replacement on a Gen1.....the rest are optional depending on wants, needs, expectations, usage and budget.
Dave

Yes, my thoughts, too.

Jason
 

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Since the topic of "Thermo-Bob" came up, maybe the group can refresh my memory.

Since I couldn't buy an new 2019 or even 2018 KLR, I am fitting out a low mileage 2008 with all the good stuff off my other two hi-mileage KLRs. I don't want to reuse my "homemade" Thermo-Bob that worked with an IMS 10 gallon gas tank, but involved drilling and tapping a hole in the water jacket of the head near the spark plug. I think I have read that the newest Thermo-Bob that mounts on the stock thermostat location on the head will not fit under the BIG IMS tank.

Does anyone know if the new Thermo-Bobs will work the the IMS 10 gallon tank or do I have to use one of the older ones?
 

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@GoMotor,

The Thermobob 2 will not fit under the IMS tank. What will work is the ThermoBob 3 mounted down low at the radiator's outlet. It may fit up near the head in the conventional position, but with the IMS 10 things get pretty tight up there.

The ThermoBob 3, mounted this way, worked really well for me. Took a bit of sorting as I think the first t-stat that I installed was bad.

Remember this thread? https://www.klrforum.com/2008-klr650-wrenching-mod-questions/47505-thermo-bob-3-a.html

Bill designed the 'backward' set-up; that's his sketch in the thread.
 

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Regarding the "Thermobob", it appears to introduce multiple leak paths into the cooling system in order to produce marginal benefits.

So, circling back to GoMotor's question about the Thermobob working with the IMS gas tank, it seems to me that the simplest and perhaps the most reliable solution is to install the IMS gas tank sans Thermobob.

Jason
 

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Regarding the "Thermobob", it appears to introduce multiple leak paths into the cooling system in order to produce marginal benefits.

So, circling back to GoMotor's question about the Thermobob working with the IMS gas tank, it seems to me that the simplest and perhaps the most reliable solution is to install the IMS gas tank sans Thermobob.

Jason
I also was concerned about additional joints......but after much reading and research I concluded that the additional risk of leaks from the added joints was minor compared to the potential benefits.

YMMV

Dave
 

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I also was concerned about additional joints......but after much reading and research I concluded that the additional risk of leaks from the added joints was minor compared to the potential benefits.

YMMV

Dave
Indeed, you are in BIG company with your thoughts about the benefits of the Thermobob.

I assume you have deduced from my last post that I don't have a Thermobob installed on my bike. Notably, I use my KLR for short errands and the occasional excursion and have only 28,500 miles on my 2012 KLR bought new in 2013. So, maybe at 50,000 miles my bike will blowup because it has been ridden without a Thermobob, but I doubt it.

I am certainly in the minority, but feel we need some opposing views in order to keep things "balanced".

Non-believer,

Jason
 

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I also was concerned about additional joints......but after much reading and research I concluded that the additional risk of leaks from the added joints was minor compared to the potential benefits.

YMMV

Dave
PLUS 1!

Indeed, you are BIG company with your thoughts about the benefits of the Thermobob.

I assume you have deduced from my last post that I don't have a Thermobob installed on my bike. Notably, I use my KLR for short errands and the occasional excursion and have only 28,500 miles on my 2012 KLR bought new in 2013. So, maybe at 50,000 miles my bike will blowup because it has been ridden without a Thermobob, but I doubt it.

I am certainly in the minority, but feel we need some opposing views in order to keep things "balanced".

Non-believer,

Jason
I personally installed an Original Thermo-Bob onto my 1987 with 60,000+ miles on its Original hoses back in 20?? prior to my quest of engine oil consumption reduction / lubrication modifications.
My 32 year old hoses have not leaked a drop of coolant from any of the four Thermo-Bob connections or any other connection.
The bike is now crowding 84,000 miles on All of its original oem hoses!

(Whoops, I disposed of the 4" clear vinyl battery vent hose 2 years ago when I installed a lithium battery. But I left the large black battery drain hose on to 'look' original.)

Jason, Those "short errands" are the primary reason that I would recommend a Thermo-Bob & my oil flow mods to a rider in a warmer climate. Get the Engine Oil UP to temp quicker & keep it there for the duration of the ride.
(Jason, What are your thoughts about an automotive pcv valve on a KLR?)
 
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