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Discussion Starter #1
I'm curious if anyone knows the REASON the thermostat by pass came to be, What set of circumstances inspired this creation?

is it
Cold Running at low rpm causing the temp swings?

Outside air Temp being cold causing temperature swings?

other circumstances ?

curious what the original intention was
 

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Lots of info on this in other threads and on Tom’s Souperdoo site. See the Recommended Reading links below. Short answer is the engine runs cold most of the time, and the temp swings you asked about.
 

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Short answer is the engine runs cold most of the time, and the temp swings you asked about.
True enough, I think! Dissatisfaction with nominal operating temperature considered too cool for lubrication optimization, and frequent temperature excursions up and down (the dreaded heartbreak of, "heat cycling").

Now, an intimate and seldom-discussed question: With NO temperature gauge (don't think the 2022 has one), how will riders KNOW they need a Thermo-Bob (radiator bypass)?????????

Without a coolant temperature gauge, riders will have no idea what nominal operating temperature might be (an "idiot light" might warn of over-heating, but not disclose ordinary service life temperatures). Further, without a temperature gauge, riders will not know how often and how far the coolant temperature rises and falls, operating beneath a, "TOO HOT!" signal from an idiot light.

Not the first Kawasaki with no temperature gauge; Versys 650 has only an idiot light, IIRC.
 

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I'm curious if anyone knows the REASON the thermostat by pass came to be, What set of circumstances inspired this creation?
I'm surprised that you might even ask this question Grant. I didn't feel that the system was correct even in 1987.
Have you not read all of this? If not I suggest that you do so. Directly from the inventor.
 
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Now, an intimate and seldom-discussed question: With NO temperature gauge (don't think the 2022 has one), how will riders KNOW they need a Thermo-Bob (radiator bypass)?????????
When their engine Oil Level Window gets 'Milky' from too many cold starts & too short of runs, they will come here asking why it happens and what they can do about it.

Do you all know How to Extract, clean & re-install most oil windows, without breaking them?
 

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Dummy light comes on, too late for me. Radiator cap with mechanical temp gauge viewable from riding position - $25
 

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Discussion Starter #7 (Edited)
Thanks for the info, thats what i thought happened. Appreciate the quick answers.

I'm going to bet the temp gauge will be part of the ENGINE light logics. (already mentioned)
 

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Discussion Starter #8
Lots of info on this in other threads and on Tom’s Souperdoo site. See the Recommended Reading links below. Short answer is the engine runs cold most of the time, and the temp swings you asked about.
i wanted the short answer, but thanks for the info ;) (i'm lazy sometimes and i knew someone here would know)
 

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You can probably run a led light conected to operate at the same time as cooling fan to get a coolant temp estimate, i did it to my c model as it comes equiped with only idiot light which never came on, and fan led only comes on during the summer time. It is a rough guess I know but better than nothing.
 

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I had an LED installed on the dash to tell me when the fan was on. At speeds over about 55 the fan would begin to turn from the air blowing through the radiator. The fan motor became a generator, illuminating the LED.
28467

Back to the drawing board went I!
 
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I had an LED installed on the dash to tell me when the fan was on. At speeds over about 55 the fan would begin to turn from the air blowing through the radiator. The fan motor became a generator, illuminating the LED.
View attachment 28467
Back to the drawing board went I!
No, NO!

Leave it!

My riding partner has a similar arrangement on his 105,000 + mile Generation 2; I always thought the setup was intriguingly, 'way cool!

Alternatively, I wired up a dashboard "jewel" lamp with the thermal switch wiring; jewel glows ONLY when the thermal switch is closed, not when the fan "free-wheels."

Shown: Jewel, with superfluous (when thermal switch operational) manual fan switch.

 

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Just wire it from any positive to resistor-led positive-led negative-fan termo switch on gen1
 

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I used 5mm warm white led with 470 ohm resistor it is very visible near instrument cluster with only 20 miliamps of current draw.
 

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Dummy light comes on, too late for me. Radiator cap with mechanical temp gauge viewable from riding position - $25
So you really think that an actual over-heat light that only comes on at say 260F & above is Worse than a Lying mechanical gauge like the one from RMATV/MC?

With Yellow caution zone beginning at 150F & RED Zone beginning at 212F. Both of which are WAY too Low for any modern cooling system with a pressure cap & anti-freeze/anti-boil coolant on gasoline powered internal combustion engines.
If the Yellow started at 230F turned to Orange at 250F and then to Red at 260 or 270F I wouldn't mind one of those gauges. As it is currently manufactured it will only further confuse Too Many people, IMO.

The ideal temps for modern engines with modern engine oils is between 195 & 230F, this is the Green zone.
 

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You can probably run a led light conected to operate at the same time as cooling fan to get a coolant temp estimate, i did it to my c model as it comes equiped with only idiot light which never came on, and fan led only comes on during the summer time. It is a rough guess I know but better than nothing.
C model,
As I understand it from Kawasaki service manuals, the European KLR650C and the USA KLX650C models both used the same coolant temp over-heat warning light system.
When in Neutral both the neutral light & the Flashing red Temp light would be on (proves the bulb operates). When shifted into any gear the Temp light & Neutral lights would turn off. IF and only if the engine coolant temp Exceeded the switch point would the RED Temp light turn ON while in gear.

Someone may have removed your temp light bulb because they didn't understand the system or it might have a burned out bulb, if the temp warning light does Not operate while in Neutral.
If the temp light operates while in neutral and has never turned on while riding in gear then your cooling system has never over-heated, so the light needn't be lit.
 

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C model,
As I understand it from Kawasaki service manuals, the European KLR650C and the USA KLX650C models both used the same coolant temp over-heat warning light system.
When in Neutral both the neutral light & the Flashing red Temp light would be on (proves the bulb operates). When shifted into any gear the Temp light & Neutral lights would turn off. IF and only if the engine coolant temp Exceeded the switch point would the RED Temp light turn ON while in gear.

Someone may have removed your temp light bulb because they didn't understand the system or it might have a burned out bulb, if the temp warning light does Not operate while in Neutral.
If the temp light operates while in neutral and has never turned on while riding in gear then your cooling system has never over-heated, so the light needn't be lit.
Sorry for missunderstanding, actualy it works as You have described, it is lit in neutral and goes off when you shift in gear, it just did not come on during normal operation, but then again it should not if everyting is functioning properly. On the termoswitch is stamped 120 as it probably opens circuit at 120 celsius when coolant boils totaly. Thats really a idiot light so I added a led to tell me when the fan comes on approx 100-105 celsius.
 

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Discussion Starter #19
I had an LED installed on the dash to tell me when the fan was on. At speeds over about 55 the fan would begin to turn from the air blowing through the radiator. The fan motor became a generator, illuminating the LED.
View attachment 28467
Back to the drawing board went I!
now you'll see a bunch of KLR's with the AUGMENTED charging system LOL
 

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Discussion Starter #20
its a shame i have to bite my tongue so much in this forum for fear of starting another HUGE war over my theories. :(
 
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