Temperature bobbing

[The Doctor]

So, went on a lengthy ride the other day. While on the highway slab, I was going 75 or so, and the ambient temperature was about 40 degrees F. It was a long flat slab of interstate, so I noticed something happening with the instrument cluster. The temp gauge would vary between 1/4 and a 1/2 repeatedly. It would slowly build over the course of about 15 or 20 seconds. And then when it got to the 1/2 mark, it would fairly rapidly (2-3 seconds) drop back down to the 1/4 mark.

Any history with these problems, or ideas as to what might be causing it? Should I be worried? I'm using distilled water, Water Wetter, and a dash of anti-freeze (freezing isn't the big concern in Southern Nevada, but we can get right around freezing). I changed the fluids when I got the bike and made sure they were at appropriate levels. I've checked a time or two and everything seems to be topped off.

[CRocker]

Doesn't sound like a "problem" to me...probably just the thermostat opening and closing...sounds normal...

[DC Concours]

At 40 degs and at those speeds w/o any stop and go-- your gauge should rarely if ever go slightly above the warm-up block. Mine never goes to the middle while in motion on a cold day or a hot day for that matter.

How's the gauge in the summer?

[The Doctor]

At 40 degs and at those speeds w/o any stop and go-- your gauge should rarely be 'slightly above' the warm-up block. Mine never goes to the middle while in motion on a cold day or a hot day for that matter.

How's the gauge in the summer?

No clue. Just picked it up late October, so haven't had the chance to have it in any hot weather yet.

[SteveJ.]

It's the thermostat cycling. Really not the best thing for the engine as it is cycling between a good operating temp and getting slammed with very cold coolant.


Cover up the oil cooler will help. Cover some of the radiator if that doesn't do it. A SuperStat thermostat from Stant will also help with this. I ran one, a 195* Worked well in the heat and cold and maintained a much better temp for the engine.

The best solution is a Therm-O-Bob. Google is your friend.

[MAN OF BLUES]

So, went on a lengthy ride the other day. While on the highway slab, I was going 75 or so, and the ambient temperature was about 40 degrees F. It was a long flat slab of interstate, so I noticed something happening with the instrument cluster. The temp gauge would vary between 1/4 and a 1/2 repeatedly. It would slowly build over the course of about 15 or 20 seconds. And then when it got to the 1/2 mark, it would fairly rapidly (2-3 seconds) drop back down to the 1/4 mark.

Any history with these problems, or ideas as to what might be causing it? Should I be worried? I'm using distilled water, Water Wetter, and a dash of anti-freeze (freezing isn't the big concern in Southern Nevada, but we can get right around freezing). I changed the fluids when I got the bike and made sure they were at appropriate levels. I've checked a time or two and everything seems to be topped off.

Couple of things come to mind;

thermal sensor may be compromised; the tab on the sensor is frequently been known to become "loose" as its a riveted on blade tab. Over time, it does not keep providing a good connection to the "guts" of that thermo unit, and may be the cause for the rapid changes in the gage.
Secondly, (and I'm sure you are  watching that,) the fluid level in the bike may be dropping below the sensors "bubble" of flow, may not be evident, but surely makes people chase the syndrome.. insure a full system, burp from w/p, and also the thermo housing.

Thirdly
maybe the thermostat is slightly and slowing becoming a lump of non functioning metal, so removint the housing and thermostat, and replacing with one of the many available we have and can be found in the common parts list, will help.

now on to Steve...

So, went on a lengthy ride the other day. While on the highway slab, I was going 75 or so, and the ambient temperature was about 40 degrees F. It was a long flat slab of interstate, so I noticed something happening with the instrument cluster. The temp gauge would vary between 1/4 and a 1/2 repeatedly. It would slowly build over the course of about 15 or 20 seconds. And then when it got to the 1/2 mark, it would fairly rapidly (2-3 seconds) drop back down to the 1/4 mark.

Any history with these problems, or ideas as to what might be causing it? Should I be worried? I'm using distilled water, Water Wetter, and a dash of anti-freeze (freezing isn't the big concern in Southern Nevada, but we can get right around freezing). I changed the fluids when I got the bike and made sure they were at appropriate levels. I've checked a time or two and everything seems to be topped off.

 

It's the thermostat cycling. Really not the best thing for the engine as it is cycling between a good operating temp and getting slammed with very cold coolant.


Cover up the oil cooler will help. Cover some of the radiator if that doesn't do it. A SuperStat thermostat from Stant will also help with this. I ran one, a 195* Worked well in the heat and cold and maintained a much better temp for the engine.

The best solution is a Therm-O-Bob. Google is your friend.

hey man, hope the road is having a good effect, seems to be great, and I always wanna hang with ya..
but.....
ThermoBob may be great for a KLR, which was it's intent... (unfortunately they ain't around anymore. Have you visited or queried one lately?.. so....) but for a Conni, well, nothing can be gained by it.  just relating what I found a couple months back...

best bet for a C10, operating correctly, with no coolant or air leaks with the cooling system, (good seals on logs, thermostat housing, hoses, etc., ) is playing with thermostat temperatures, or the temps they open, and close at...

I think both Bubba Steve and I both agree that covering radiators is not a really good thing to do, but I'll leave that up to him to explain... as he and I have both discussed this.
not saying it won't "help", but it shouldn't be relied upon as a cure all.

any way, that's my "old fart-obvious response" in order to stay p/c, especially since I've been called that among other things recently, by someone that sent me a letter...
 

I'm still laughing about you being mistaken for SISF.... 

[DC Concours]

You know MOB, you used to be a lot worse a couple of years ago. A cranky old man.

But lately you have been very jovial. I miss the cranky old man. What happened? You got a mistress?

any way, that's my "old fart-obvious response" in order to stay p/c, especially since I've been called that among other things recently, by someone that sent me a letter...
 

[SteveJ.]

I'm still laughing about you being mistaken for SISF.... 

Not the first time it's happened, but still...

ThermoBob may be great for a KLR, which was it's intent... (unfortunately they ain't around anymore. Have you visited or queried one lately?.. so....) but for a Conni, well, nothing can be gained by it.  just relating what I found a couple months back...

https://shop.watt-man.com/Thermo-Bob-1-Kit-for-Kawasaki-Concours-1986-2006-1-fittings-TB1.htm

I saw the charts and graphs for the Versys and was convinced and got one. Stable temps really are a good thing for engines.

Worncog has a T-bob on his c-10 and likes it.

As far as the covering the radiator thing goes I really don't see an issue as long as you keep an eye on the temps. I may need enlightening, however.

I never covered the oil filter or radiator and the 195 Stant Superstat did a yeoman's job of reducing the temp swings to the point of being good to go. I ran the bike here in the winter with several mornings in the 30's and a lot in the 40's. I refused to ride it under freezing as I had a curvy bridge over a river that frosted up when it was that cold. Frosty bridges with curves were/are a show stopper for me. Besides, my El Camino needed to be driven once in a while and the heater worked quite well. 

Hoping your weather doesn't suck too bad up there. Later. 

[MAN OF BLUES]

You know MOB, you used to be a lot worse a couple of years ago. A cranky old man.

But lately you have been very jovial. I miss the cranky old man. What happened? You got a mistress?

any way, that's my "old fart-obvious response" in order to stay p/c, especially since I've been called that among other things recently, by someone that sent me a letter...
 

don't worry, I've been keeping close tabs on trying to be more "kinder  and gentler  " these days... every time I let the "curmudgeon" out of the pocket, I get told about it.. so it's best for me to be kind.
 

[The Doctor]

You know MOB, you used to be a lot worse a couple of years ago. A cranky old man.

But lately you have been very jovial. I miss the cranky old man. What happened? You got a mistress?

any way, that's my "old fart-obvious response" in order to stay p/c, especially since I've been called that among other things recently, by someone that sent me a letter...
 

don't worry, I've been keeping close tabs on trying to be more "kinder  and gentler  " these days... every time I let the "curmudgeon" out of the pocket, I get told about it.. so it's best for me to be kind.
 

[DC Concours]

No MOB. I want the cranky old bastard back. I loved him. Dont worry about all the little snowflakes on here who cannot handle you. They can eat sh^t.

[MAN OF BLUES]

No MOB. I want the cranky old bastard back. I loved him. Dont worry about all the little snowflakes on here who cannot handle you. They can eat sh^t.

 

you guys crack me up....
don't make me "bring 'Ol Painless" outta the bag....

https://youtu.be/K63AVSCPcSI

http://youtu.be/K63AVSCPcSI

https://youtu.be/NrDG4sPul8w

http://youtu.be/NrDG4sPul8w

happy now????
 

[LeeM]

First, pay attention to comment from Man of Blues. The next question is where is the temperature sender unit?  Can you reach in and jiggle the electrical sender? Man of Blues comment leads me to think I should find the temperature sender, reach in with a short stick and see if tapping the connector affects the gauge reading.

In any case, you will probably do some work in the thermostat and thermostat housing.

Removing the right side cover will make the thermostat housing partly visible. I had to work on this area of my 2000 Connie not long after I bought the bike 3 years ago. My bike developed puzzling temperature behavior. When I looked at my thermostat housing, I saw some white crust indicating coolant leaks. The 8" long straight hose was a visible new item on my bike. The previous owners had been there before me.

On the thermostat housing parts, the housing gasket is an odd item I recommend you buy. The thermostat inside is a conventional small automotive form factor. The COG repair pages list replacement thermostats. The 8 inch straight water hose leaving the thermostat has to be replaced with a Japanese sourced part. A piece of 1 inch inside diameter Napa Auto Parts radiator hose does not seal up nicely. If you have the original Japanese hose clamps, re-use them. American made stainless screw drive hose clamps are too big and clumsy for the tight clearances in the Connie.

A specialist vendor called murphskits.com sells the thermostat housing gasket and a thermostat that fits.

I have a radiator pressure tester with a small radiator neck adapter. You pump up the cooling system with air to 14 psi. Cooling system leaks are revealed in a few seconds with air pressure;.  Mentioned earlier is the task of "burping" the cooling system. There are several schools of thought on how to do this. NFMTTYH. You'lll see!

Yet another part of the erratic temperature problem is the condition of the motorcycle battery and does your battery have good ground wire connection.

Best wishes and welcome. Keep us posted on your progress.

[tdbru]

i stuck a thermo-bob in my C10 umm.... darn.......  been while..  5 years ago?  more?  anyway.  other than idling at the stop light in the summers waiting for the green light, the temp gauge comes up and stops ~1/4 and stays there like a rock.  when i sit at the stoplight, though, waiting for the light to change in the summer it goes up to 1/2 where the fan kicks in and stops there until i get moving again.  then it drops down to 1/4 and stays there.  i did a write up on it for the Concourier and sent it in but can't remember if it ever got pub'd. 
can't wait for spring riding season.
tdbru

[Mcfly]

Another happy thermo-bob customer here.  Rock steady temps.  I also like the new thermostat location.
Having a by-pass cooling system isn't a bad thing!   

[Gitbox]

I put a Thermo-Bob on my old C10 and it cured the bobbing temps. It made the cooling system act just like my car's cooling system - quick warm up and then steady temps.

Man, I had so many mods on that thing...

[MAN OF BLUES]

Another happy thermo-bob customer here.  Rock steady temps.  I also like the new thermostat location.
Having a by-pass cooling system isn't a bad thing!   

sooooo, let me get this straight, and understand better.... did you remove the existing thermostat, and just run the one that comes with the thermo-bob?

or are you actually running 2 thermostats....?

I'm not getting this all, and I have looked at the "Bob", and it's installation, and function... and see a double thermo as a failure point, also, when examining the "Bob", I can see a simpler "way" to emulate the "Bob", with what is already on the bike, with the addition of a couple fittings/hoses/ and some creativity...
which reduces the thermostat (2 vs 1) failure rate to a single point.

It's all good tho, and the "Bob" was a very creative invention, just not suited for my simplistic maintenance thought, and weather needs.

If it works for you, it is all that matters...

[Mcfly]

Another happy thermo-bob customer here.  Rock steady temps.  I also like the new thermostat location.
Having a by-pass cooling system isn't a bad thing!   

sooooo, let me get this straight, and understand better.... did you remove the existing thermostat, and just run the one that comes with the thermo-bob?

or are you actually running 2 thermostats....?

I'm not getting this all, and I have looked at the "Bob", and it's installation, and function... and see a double thermo as a failure point, also, when examining the "Bob", I can see a simpler "way" to emulate the "Bob", with what is already on the bike, with the addition of a couple fittings/hoses/ and some creativity...
which reduces the thermostat (2 vs 1) failure rate to a single point.

It's all good tho, and the "Bob" was a very creative invention, just not suited for my simplistic maintenance thought, and weather needs.

If it works for you, it is all that matters...

The system requires the OEM thermostat to be removed.  Just an empty housing there now.  A new thermostat housing is cut into the system just
forward of the fill pipe.  A smaller diameter hose attaches to the new housing, and runs to a tee at the exit hose of the
radiator, thus by-passing...  Thermostat closed coolant continues to warm/circulate through the bypass.  Thermostat opens,
and the coolant goes through the radiator.  A simple but effective mod that minimizes cold weather coolant temp cycling, and
maintains a steadier coolant temp in cooler weather at speed.  No effect on hot summer days...  the needle stays
pinned at 1/4 up, hot or cold weather until air stops going through the radiator.



There's the new housing... the bypass is visible at the top (forward on the bike). 

Hope this clears up the mystery MOB.  I'll admit the TEE that goes in the pipe exiting the radiator is a PITA
to get situated right, with all the hose clamps and the tight area you get to work in, but tinker, tinker....   

[MAN OF BLUES]

 
thanks