Thermostat Replacement

V4RDR

V4RDR

Joined
Nov 12, 2020
Messages
15
Age
62
Location
Florida
Hi everyone.

I recently bought a black 2010 ST with 13K miles. I have been on my gen 5 VFR for years and finaly decided it was time for a more upright ride, and wanted to stay with the bulletproof Honda V4 line. I have ridden friend ST's for years but never had the heart to let my bike go. So I decided for now my garage is large enough for both.

I was able to find some details on the maintenance performed before I owned it. The one thing I think was not done was the coolant, so I decided even though with low millage, 10 years old it should probably be tackled. The existing was green that I assumed was OEM (after reading many posts), but had no way to be sure, so I elected to remove the radiator and do a complete clean and manual flush.

I was contemplating replacing the thermostat while it is exposed. As I read the posts, it seems there may be an eventual need for this service because of some failures. If so, what would be the best replacement brand and temp range for the southeast humid climate ?

Thanks - Any input would be appreciated.

Great forum !!
 
Go with OEM for the thermostat and save yourself some hassles. The bikes temperature is critical for this picky bike! :)

I'm not sure what color the OEM coolant is but you can use Honda vehicle coolant and it's blue. I believe it's their type 2.

Good time to snug up the coolant hose clamps as they seem to need it periodically.

Lots of how to's in the article section at the top of the page.

Good luck
 
The problems with early OEM factory installed thermostat failures seemed to be fixed by the 2007 models FWIW.

For many years we were not able to use any thermostat other than OEM - no other ones would fit but recently some one posted that a certain aftermarket or OEM Diahatsu one would fit but for the life of me I can’t find the thread. Maybe someone will chime in. It was only a few weeks ago but I couldn’t find it in the ST1300 Tech>Thermostat sub forum.

https://www.st-owners.com/forums/forums/st1300-thermostat.458/

My own replacement choice would be OEM but if I had a post 2007 ST1300 I would not replace it without cause.
 
dduelin said:
The problems with early OEM factory installed thermostat failures seemed to be fixed by the 2007 models FWIW.

For many years we were not able to use any thermostat other than OEM - no other ones would fit but recently some one posted that a certain aftermarket or OEM Diahatsu one would fit but for the life of me I can’t find the thread. Maybe someone will chime in. It was only a few weeks ago but I couldn’t find it in the ST1300 Tech>Thermostat sub forum.

https://www.st-owners.com/forums/forums/st1300-thermostat.458/

My own replacement choice would be OEM but if I had a post 2007 ST1300 I would not replace it without cause.
Click to expand...
Here you go Dave

Thermostat FYI | ST1300-Thermostat

If you are ever traveling and your thermostat goes the Dihatsu Terrios use the same one our bike does
www.st-owners.com www.st-owners.com
 
Best brand of 'stat replacement? Like most things, best is in the eye of the beholder. A broad consensus here, goes with OEM (I do too), and when you consider the cost in time and effort of doing it again, there is not a tremendous cost savings. Once you have the radiator out, you will have to remove the frame crossbar in front of the stat housing. Don't forget to buy a new o-ring with your stat, and you might consider replacing the hoses if they are not firm and strong. Look for any corrosion around the stat housing's spigots and clean the aluminum thoroughly. When I did mine, I put on Breeze constant tension clamps, replacing the narrow OEM ones. No more leaks. These will require careful positioning of the spring end, since it is so large. I also replaced the two big hoses leaving the radiator. A dab of silicone grease (rubber friendly) made slipping them on the spigots easy. Don't overtighten the hose clamps on the radiator end - you can crush the metal.
 
Don't forget to take a plumbers brush and remove the black paint from the inside of the pipes on the radiator.
On just about every ST I've opened up, I've found the black overspray inside the spouts blistered up and flaking off, all throughout the entire cooling system.
This is what clogs up the Idle wax valve lines etc.
The bike I did last Sunday had several large pieces of paint that had jammed inside the spring of the T-stat not allowing it to work properly.
When the bike came in, the temps were 132+, after T-stat replacement, coolant flush, and TB sync, and idling for almost 30 minutes on the lift table, the temps were 82 degrees.
Small things make a difference.
For the longest time, folks thought there was a problem with the Honda T-stat, when in reality, it was the overspray in the pipes on the radiators that was causing all the failures etc.
:doh1:
 
Thanks for all of the responses.

I went with a double flush and brush clean the inlets, Honda type 2 blue, and no thermostat change (no cause to). The bike is solid on three bars and runs perfect.

Love the ST !!
 
V4RDR said:
Thanks for all of the responses.

I went with a double flush and brush clean the inlets, Honda type 2 blue, and no thermostat change (no cause to). The bike is solid on three bars and runs perfect.

Love the ST !!
Click to expand...
Three Bars is where they all remain once warmed up.
When you looked at the T-stat was it short and squat, or tall and extended?
The barrel should be bright and shiny, not a dull green or grey color.
An indication of whether your T-stat needs to be replaced is How Long does it take to reach 3 bars?
You should have the first bar in a minute or two, and by the time you put your gloves and helmet on, you should have three bars showing in no more than 3 to 4 minutes.
This is a BAD T-stat and should be replaced, as its stuck in the open position.

20170604_131054 (1).jpg

And this is one starting to fail (see the scrape marks on the barrel) these are very slow to reach three bars, or do the old two bar - three bar shuffle.
20170810_141124.jpg

And these were all either bad, or going bad.
045.JPG
037.JPG
 
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I changed my thermostat out when I changed the fluid and tightened the hose clamps at 40,000 kms just because I was in there and I just acquired the bike. I wasn't sure if it was operating correctly, but it did always go to three bars and stay there. The new one acted exactly the same, as far as I can tell.
My temp gauge does show one bar in the first few minutes but I only get 3 bars a mile down the road. Must be the outside temperature. It's rarely in the 90's when I start out.
Good information and pictures of what to look for on the thermostats!
 
That would depend on how often you service the coolant, flush the system, what coolant you use, and several factors about the overall condition of the bike, is it out of tune? does it run hot?
What area is the bike stored or ridden in? Do you live in the desert or near the ocean? At sea level or at 12,000 foot altitude? etc.
How's that for avoiding a direct question?
I should be in politics :rofl1:
 
dduelin said:
The problems with early OEM factory installed thermostat failures seemed to be fixed by the 2007 models FWIW.

For many years we were not able to use any thermostat other than OEM - no other ones would fit but recently some one posted that a certain aftermarket or OEM Diahatsu one would fit but for the life of me I can’t find the thread. Maybe someone will chime in. It was only a few weeks ago but I couldn’t find it in the ST1300 Tech>Thermostat sub forum.

https://www.st-owners.com/forums/forums/st1300-thermostat.458/

My own replacement choice would be OEM but if I had a post 2007 ST1300 I would not replace it without cause.
Click to expand...

i posted it. A Dihatsu 1.3 ltr motor has the same thermostat. They are used in Terios models which are very popular in “3rd” world countries like here in Costa Rica. Cost about $5.00

enclosed is a reply to the post. Hope it helps
 

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