Thermo-Bob 3 - Page 4 - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

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post #31 of 38 Old 09-26-2019, 07:19 PM
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Quote:
Originally Posted by Norton 850 View Post
I agree.

I've spent years, ~19, designing and working on Multiplex hydraulic control systems for use on subsea BOP stacks and for the sake of reliability, you always strive to minimize the quantity of potential leak paths on a hydraulic control system. I'm in the minority when I say this, but the advantages of the Thermobob do not offset the cost of the system and the inherent increase in failure points.

But if you enjoy adding stuff to your KLR, you could do far worse than installing a Thermobob. So, if it's caught your eye, go for it. But the Thermobob should be way down on the list of things you need to do to get that bike up to scratch.

Jason
Well, I'll defend the use of 6 additional hose clamps to allow the use of a proper radiator by-pass system to bring the ENTIRE engine temperature up to a more 'modern' 195F+, as quickly as possible.

I installed my Thermo-Bob shortly before I began my engine oil flow alterations. Because I realized the potential 'benefits' of higher / more stable engine temperatures, than the stock 160F, with extreme fluctuations.

But if one wasn't ever going to install an IMS 10 gallon fuel tank I would suggest that one should use the Thermo-Bob 2.

pdwestman
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post #32 of 38 Old 09-26-2019, 08:25 PM
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Originally Posted by pdwestman View Post
Well, I'll defend the use of 6 additional hose clamps to allow the use of a proper radiator by-pass system to bring the ENTIRE engine temperature up to a more 'modern' 195F+, as quickly as possible.
Paul, with all due respect, you missed a couple of potential leak paths: the NPT fitting; the SAE o-ring fitting on what appears to be a temperature transducer; and the four-bolt o-ring connection on the thermostat housing.

I agree that there are compelling reasons why there may be benefits to adding the Thermobob to the KLR cooling system. But those benefits are difficult if not impossible to measure. And if you can't quantify the benefits, then in my mind it's not worth the added complexity.

Please note that I don't look disparagingly at folks that want or have a Thermobob. Notably all the respected long-standing members of this forum and other KLR forums have them. And like I said in a previous post, there are much worse modifications you could make to a KLR.

Jason
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post #33 of 38 Old 09-27-2019, 09:57 AM
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Jason,

Though I don't have your background, I had similar concerns about the added risk of additional leakage/failure points. I've gone to some effort to reduce/eliminate all known weak spots and problem areas from my KLR's so it was a concern for me. After careful consideration and review of all available data, I decided (right or wrong) that the added risk of leaks was more than offset by the benefits afforded by the Thermobob set up and the more stable cylinder temperatures. I'd note that both the advantages of the T bob AND the increased likelihood of leaks due to the additional joints is impossible to quantify.

In some ways this reminds me of the argument from the DR and XR guys that thier bikes are superior due to the lack of liquid cooling and associated parts/increased risk of failure....while the complexity of liquid cooling does add failure points, I believe that neither of those bikes approach the KLR's potential longevity due to it's far more stable engine/oil temperatures....especially with a thermobob.

As always, thanks for your intelligent and thoughtful posts and opinions.

Cheers,
Dave
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post #34 of 38 Old 09-28-2019, 06:09 AM
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Yea I have to agree. The benefits far outweigh the risks of having multiple “failure points.” It’s just a simple motorcycle engine from the 80’s.... it’s not like we’re screwing around with some new modern day automobile cooling system.

Please do not lecture me on the effects of temperature and density altitude on an internal combustion engine -Thank you.

2003 KLR650.... With all the bells and whistles
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post #35 of 38 Old 10-02-2019, 07:26 PM
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Quote:
Originally Posted by Tom Schmitz View Post
Here's a picture of my Thermo Bob Original in the usual place...It works great and always has. It's perfectly positioned and doesn't shake, rattle, or roll. The problem is that it tends to get in the way when I need to get the valve cover off. Since I'm constantly fiddling with stuff, that's a nuisance.
Tom
Taking off the valve cover and drilling out that broken-off bolt allowed me to make two discoveries on my new-to-me 2008 KLR.
1. It has a thermobob and, by the size of it, probably a gen 1.
2. Trying to get the valve cover off, or even just lifting it up and moving it out of the way by a few inches is kind of a pain with the TB being where it is.

I'm contemplating deleting it vs replacing it with one of the smaller gens. A couple questions if you don't mind...

Is there a way to tell for sure what gen it is?

Currently, the bike's temp runs mid level on the temp gauge, goes way up at stop lights, then back down to mid level when the bike gets going again. Without the TB, what would the gauge likely be doing?

Last edited by Schoen; 10-02-2019 at 07:39 PM.
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post #36 of 38 Old 10-02-2019, 07:34 PM
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I'll recommend that you leave the Thermo-Bob installed, ignore the temp gauge unless the needle is Actually touching the RED-ZONE and remove at least the TOP radiator mounting bolt and allow the radiator & T-Bob to rotate Forward and away from the valve cover & head during valve tappet inspection & adjustments.

pdwestman
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post #37 of 38 Old 10-02-2019, 07:56 PM
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Quote:
Originally Posted by Schoen View Post
Currently, the bike's temp runs mid level on the temp gauge, goes way up at stop lights, then back down to mid level when the bike gets going again. Without the TB, what would the gauge likely be doing?
The Thermobob will not stop the temperature from rising at stop lights; that's normal behavior with or without Thermobob. The fan should start running and keep the temperature needle from entering the red zone at stop lights.

During continuous riding, the temp needle should be at about half scale if a Thermobob is installed. Without a Thermobob the temp needle drops down to just above the lower normal mark on the scale during continuous riding.

Jason
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post #38 of 38 Old 10-03-2019, 09:45 AM
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To add to what's been said;

- it should be obvious which thermobob you have; the Original is an inline pce, the Thermobob 2 is a replacement T stat housing; Information, Articles

- functionally they are the same but the 2 is a cleaner install. Whether or not it's worth replacing an Original with a TB2 depends on your budget and how often you plan on having the valve cover off...


The gauge only shows you a small part of the picture with regards to what the thermobob does. Read the "testing results/history" tab on the link above to learn more.
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