Confirmed TT thermostat failure

Hi,

While I was setting up the test equipment for the temperature testing that I did, I disassembled my thermostat housing to install the thermocouple. To my surprise, I found the thermostat broken at the bypass valve. There was no indication that there was any kind of a problem as the thermostat was still functioning.

I have no idea what may have caused this. There is no signs of corrosion on any of the parts.

It has been in operation just over 2 years and about 30 K. It is one of the proto type parts that I originally began testing.

I would like for anyone that has had the Motorad thermostat in operation for over 1 year, do an inspection of their unit to deturmine if this is an isolated problem, or if it is a design problem with the unit.

Thanks Tom

Tom,

I don't have any thermostat info as I still have the original. I just ordered one from TC.
I DO want to heartily congratulate you for your business practices. I don't know of very many places that would make as honest a posting as you have.

Also your response on the material length in the ST header wrap kits.

Herb
'03 ST

Tom, I haven't had the time to pull mine open per your/my PM's a couple weeks ago. But I intend to pull out my motorad tstat in the next couple weeks, working around business travel & other commitments. I installed it in March '08 (link) and has only about 6k on it over the 13 mos since the install. Over this past few months I do not get reliable 3 bars on the temp gage and mileage has dropped ~10mpg average.

BakerBoy said:

Tom, I haven't had the time to pull mine open per your/my PM's a couple weeks ago. But I intend to pull out my motorad tstat in the next couple weeks, working around business travel & other commitments. I installed it in March '08 (link) and has only about 6k on it over the 13 mos since the install. Over this past few months I do not get reliable 3 bars on the temp gage and mileage has dropped ~10mpg average.

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There was NO indication that the thermostat had failed. It operated perfectly as all the parts were held in place by the springs.

I have installed a thermostat in my bike that was claimed to be defective (would not hold 3 bars)- It operates perfectly. There is a lot more going on with the temperature indicator than we are seeing. I am continuing to investigate.

Thanks Tom

Understood, thanks Tom. I look forward to hearing what the thermocouple indicates and when I get it pulled I'll let you know what it shows & how it operates in a bath.

BakerBoy said:

I installed it in March '08 (link) and has only about 6k on it over the 13 mos since the install. Over this past few months I do not get reliable 3 bars on the temp gage and mileage has dropped ~10mpg average.

Click to expand...

To add my experience - I installed mine in March '08, I have about 16K on it. Through about December it would hit 3 bars on warm up and lock in, but I have since noticed it will rise to 3 bars on warm up and maybe the first mile of slow riding on local roads then drops back to 2 bars (only once to one bar air temp at ~15F) for 10-15 miles once I pick the speed up, even at air temps to 40-45F, then makes 3 bars again and locks in for good. I have not noticed an appreciable loss in MPG.

Probably will not get the plastic off to take a look until the winter and the next scheduled coolant change unless I see significant MPG loss (unlikley I would think given the change in seasons).

'Til it gives you problems. It's not going to leave you stranded. You'll see a decrease in fuel economy and, depending on the weather, an inability to maintain three bars on the temperature gauge.

--Mark

turbocity tom said:

There was NO indication that the thermostat had failed. It operated perfectly as all the parts were held in place by the springs.

I have installed a thermostat in my bike that was claimed to be defective (would not hold 3 bars)- It operates perfectly. There is a lot more going on with the temperature indicator than we are seeing. I am continuing to investigate.

Thanks Tom

Click to expand...

I don't see any problems with my temp sensor. I've pull two confirmed OEM thermostats, one stuck open and one with metal shavings. I've had your's in it since the beginning of the winter and it's holding 3 bars at all ambient temps. I like it. I hope your's is a fluke.

Ceerap! My bike just started showing signs of thermostat problems on the way home from the Hutchinson RTE this past weekend.

Is the stock Thermostat a warranty item?

Do I do any damage if I ride it like this for a while, I don't want to miss Moonshine?

FigsST said:

Is the stock Thermostat a warranty item?

Do I do any damage if I ride it like this for a while, I don't want to miss Moonshine?

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Yes, it is, but it will be replaced with another OEM unit.

No problem riding on it; just expect a drop in fuel economy.

--Mark

My OEM t-stat(2004) went south the first 8 months and I replaced it with another OEM and Honda blue auto coolant and it has been just fine for +4 years now.

FigsST said:

Ceerap! My bike just started showing signs of thermostat problems on the way home from the Hutchinson RTE this past weekend.

Is the stock Thermostat a warranty item?

Do I do any damage if I ride it like this for a while, I don't want to miss Moonshine?

Click to expand...

Yes, they are covered under warranty

After gaining a little intel on this from you folks here on the site; I contacted one of the local Dealers here in the KC metro and made an appointment to have my thermostat replaced via warranty. I turn my bike in on the Tuesday after Moonshine, and will get it back one day later...

With today's snow, I took the opportunity to open up the bike and check the Motorad thermostat from TurboTom, as I promised Tom I'd do.

For the record, Tom posted a mechanical failure above--a very different failure than what I'm discussing here. However I wanted clear up any suspicion I'd planted about a TurboTom thermostat sticking open (per my post #3 above).

My bike has recently started having the symptoms of the t-stat being stuck open: poor mileage, 1 bar for numerous miles and 2 bars for 10's of miles. It sometimes was getting to 3 bars on 40?+ days, but only after a while. But it has not been able to get to 3 bars on 25? days unless I stop and let it idle, and shortly after moving again it would drop back to 2 bars--that behavior is new for my bike and only has been seen for the last few months.

On disassembly this morning I found that the TT Motorad thermostat was not stuck open...here is a picture taken right after pulling the t-stat housing cover:


I ordered another new t-stat from TurboTom about a month ago. I put that new t-stat [white ziptie], the 1 yr old TT thermostat (the one pulled out today) [yellow ziptie], plus the original Honda t-stat [green ziptie] through numerous hot and cold baths. Here are the thermostats with colored zip strips to show which one is which, in 185?water, and in ice water:




All opened at ~185?F and closed instantly in the cold bath. I did notice that the Honda OEM thermostat moved more slowly on opening and closing than the TT thermostats.

The only anomoly I found was that the Honda OEM thermostat stuck open once during a test cycle. This surprised me as it had not failed open before I replaced it last year (see writeup). I replaced it on speculation as I'd read so much here and I was deep in the bike anyway at the time.

So, after all, sometimes even the symptoms of a stuck open thermostat are deceiving. Unless I eventually find some other cause, these "stuck open thermostat" symptoms may simply be 'normal' at low outside temperatures.

""stuck open thermostat" symptoms may simply be 'normal' at low outside temperatures."

Are you guys still using a SS rivet to plug the hole in TT thermostat? What would happen if a person used an aluminum or steel rivet with a steel inner nail (shaft)? An aluminum one wouldn't have time to electrolysize against the steel inner body of the thermostat would it? Or are most not plugging it? My climate riding ranges from 32 to 92?. I have no idea where I can find a SS one. HAd considered using a tiny bolt with two nuts to help fend off loosening due to temp change, but didn't want to chance them getting lose in the system. Any thoughts on all this?

Is there any newer updates to the thermostat re and re regarding new findings, like coolant used, the return of silt, annealing copper washers etc etc ? I've read a fair bit but not sure if I have found the newest findings.

Nothing new, replace the T-stat with either the OEM or the TurboCity one, you don't have to plug the hole in the t-stat but you do want to do a thorough flush of the system to get any contaminants out of the system. It happened to my '03 in the 1st 20k miles, hasn't happened to my '08 yes in 55k miles.. .

Thanks Joe..good to know. So when I flush, is it safe to flush in both directions? I had thought of trying to hold a small rubber hose up to the head drain bolts and all the other areas that are not too hard to get to. The ones at the water pump being the easiest of course. I ended up buying coolant at the local Honda car dealer, but ironically I can distill my own water. Wasn't sure about being able to ensure I was able to get the non-silicate free? (do we want silicate or NOT want silicate?) coolant or whether that is still a precaution with Honda water pumps? I know it sure was crucial back in the days of their CX engines..(the old V Twins 500 and 650's) ..and the GL flat 4 motors too come to think of it.

The reason I ask about flushing in both directions is because sometimes (when I have worked on a fuel system that regretted ever flushing cuz all it did was loosen well planted stuff that did end up plugging elsewhere both down and upstream) it can create a problem you didn't have before.

Mine just started showing two bars for a minute or two then back to 3 for a minute or two, after it has warmed up. Fuel milage is same so I think I'll wait till the mpgs drop. Thanks for the research, pics were great.

geronimo said:

Mine just started showing two bars for a minute or two then back to 3 for a minute or two, after it has warmed up. Fuel milage is same so I think I'll wait till the mpgs drop. Thanks for the research, pics were great.

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Just changed mine with OEM, old one was stuck open hard. Back to 3 bars, see shortly if 3 mpg come back.