Strange thing happened on the way to a Honda dealer

Went for a ride today for coffee, normal routine of warming until one bar shows up then all is well. After coffee I drive to another town to the Honda dealership where I get a discount on parts, and along the highway not far out of town, I see only 2 bars on the temp gauge. I think about this while riding and go...here is what I have been reading about with the stuck T-stat and poor mileage. So at the dealer I order my other parts, and an expensive t-stat for my girl. After leaving the building, I thought check the antifreeze dummy, So i listen to myself and do not see any in the reservoir, but it is hard to see. I dipped a stick down and none...hmmmm...added a cup of water and now its up to a good level. So on I ride and the gauge is 3 bars steady, in town, slow, faster than posted highway speeds...and all good. I changed oil tonight and checked antifreeze. All good levels and post oil change ride, 3 bars. Question is do you fine folks think this was my warning shot of an impending t-stat issue or just a low coolant deal? OAT was 13-18 degrees C and speeds varied. I do not smell antifreeze from anywhere, no white smoke, runs great and no visible leaks. The bike now has 28300 kilometers on her.

A cup or two low on coolant would not cause it to run cool, in fact no amount low on coolant would make it run cool. Enough low it runs hot.

It's been a long time ago with my '05 but IIRC correctly it did the 2-3 bar dance for a few thousand miles before sticking partially open for good. Yours could be a warning shot across the bow. My records show replacing the thermostat at 22,263 miles.

If you've ever seen an old T-stat, you'll know that they get corrosion on the body that kind of looks like moss, for lack of a better term. As they open and close (extend and retract) as they get more corrosion on them, they start to scrape and leave marks where they drag on the surface of this stuff. The two three bar dance is caused by sometimes they stick, sometimes they break free, etc. Then finally the corrosion gets so bad, they stick fully open.
Sounds like yours is on its way out. I will bet you a beer when you open yours up you'll find the body green, with shiny brass color scrape marks on the body.

Igofar said:

If you've ever seen an old T-stat, you'll know that they get corrosion on the body that kind of looks like moss, for lack of a better term. As they open and close (extend and retract) as they get more corrosion on them, they start to scrape and leave marks where they drag on the surface of this stuff. The two three bar dance is caused by sometimes they stick, sometimes they break free, etc. Then finally the corrosion gets so bad, they stick fully open.
Sounds like yours is on its way out. I will bet you a beer when you open yours up you'll find the body green, with shiny brass color scrape marks on the body.

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I will gladly buy you a beer regardless of the appearance of the stat. Once the new one arrives, I will find a rainy set of days to swap it out and take a few photos. I have read that it can come out from the front after removing the rad so a bit easier than what the service manual wants to happen. Thanks for the info.

cdnemsguy said:

I will gladly buy you a beer regardless of the appearance of the stat. Once the new one arrives, I will find a rainy set of days to swap it out and take a few photos. I have read that it can come out from the front after removing the rad so a bit easier than what the service manual wants to happen. Thanks for the info.

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I have a step by step tutorial in pdf. that is helpful when replacing the thermostat. PM me an email address and I'll send it to you.

I hate to disagree, BUT if you are low on coolant enough so that the temperature sensor is OUT of the flow it may very well read as cold.
But of course you saw it instantly as what it most likely is, because it most likely IS a bad Tstat.

JimGregory said:

BUT if you are low on coolant enough so that the temperature sensor is OUT of the flow it may very well read as cold

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That was my thought as I wasn't sure where the probe was, and of course low coolant would normally cause an overheat, but the weather was cooler. I am thinking t-stat and will monitor it until it arrives. I have a 1000 mile ride starting this friday so hope it holds on.

My t stat has been stuck open for the last 65k miles. Why I know that on cool days it takes a few miles to get to 3 bars. And on really cool days its been known to flick between 2-3 bars all day. Never had a cooling issue and bike runs perfectly, so I let it ride.

I have the T-stat in from the dealer and sitting on my work bench, and after the issue and adding the cup or so of water, I have not had a recurrence. I have ridden 1400 more kilometers and 3 bars so I may just do a rad flush and see. I have the part if it ever acts up again. BTW on these recent miles on the hwy I have put on, 55.3 MPG so no issues there.

cdnemsguy said:

55.3 MPG so no issues there.

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Nice! On the open road my best has been mid to high 40s. Good enough as I've never 'needed' fuel— always had a comfortable margin at pitstop time. But 55mpg is very respectable.

BamaRider said:

My t stat has been stuck open for the last 65k miles. Why I know that on cool days it takes a few miles to get to 3 bars. And on really cool days its been known to flick between 2-3 bars all day. Never had a cooling issue and bike runs perfectly, so I let it ride.

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No disrespect, but your not doing your engine any favors by ignoring your failed T-stat.
Would you keep driving your car with the check engine light on?
Why would you ignore a known failing part in your coolant system?
The old saying "pay me now, or pay me later comes to mind".

Very respectable mileage there. I normally get 56-59 mpg on the active indicator, on level road at 75 mph. Yesterday, I even got 61 mpg for about 20 miles with the wind behind me.
As far as your coolant flush, you should remove and inspect your T-stat when doing the flush to see if you have any black paint inside the housing/system. Also clean the paint off the radiator pipes when you have it off to prevent this in the future.

ST Gui said:

Nice! On the open road my best has been mid to high 40s. Good enough as I've never 'needed' fuel— always had a comfortable margin at pitstop time. But 55mpg is very respectable.

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cdnemsguy is from Canada like me and our Gallon is larger than yours. Your high 40s is our 55.3mpg

Your right, thanks for pointing that out.

Tdinova said:

cdnemsguy is from Canada like me and our Gallon is larger than yours. Your high 40s is our 55.3mpg

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Thanks for that. Because one hadn't occurred to me the other didn't either. I don't feel bad now!

ST Gui said:

55mpg is very respectable.

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I cant take the credit for this as I installed the Rostra CC and it is on 95% of the time, set around the 125-130 km/h range and all highway.

Fuelly has tracked over half a million ST1300 miles. Mid 40s US is what they do. I can get 50s but only under 50 mph.

I did the math with the US gallon and it computes to 45.319 mpg. any language I am happy with that and know that the temp is not a problem making the bike rich as if cold.

Canada always thinks big because our country is much wider than the USA. LOL

dduelin said:

Fuelly has tracked over half a million ST1300 miles. Mid 40s US is what they do. I can get 50s but only under 50 mph.

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Blah...Blah...Blah.... I Don't care about someone's stat's, MINE gets mid 50's @ an indicated 75-80 mph, and anyone that rides with me knows that, and yes, I've done the math, and not just trusted the idiot gauge.
So I guess my bike just runs better than yours.