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....
