Thermostat Replacement

[Mellow]

Well, sure enough, as soon as I respond to a post about my temp guage never going below or past 3 bars it starts acting funny.

Bouncing from 1 to 2 to 3 bars and taking a long time to warm up.

So, I'm assuming my thermostat is either going out or gone.

Anyone try replacing one themselves? I know it'a a warranty item but I typically do my own maint. just because it teaches me about the bike and I'd check things and look at things the dealer wouldn't spend time on.

I briefly looked at the service manual and it states the throttle body needs to be removed :shock: is that something major or just does it just sound complex?

I don't have any rides planned for the next couple months since my vacation is zero! So, I don't mind taking the bike apart and taking my time to learn my way around it as well as do some yearly fluid replacements, valve check, air filter, brake pads. etc etc...

Any advice is highly appreciated.

[Angus]

Mellow, I just brought my ST 1300 in to the Honda shop as I am running cool, 2 bars in temps in the 50's, and 1 bar when running in the 40's. My mileage normally is 50 mpg's or so, and now the last tank dropped to 44 mpg. The service mgr. who writes for a national motorcycle mag. called Honda and they told him that there never has been a thermostat failure on a ST 1300 and if it were to fail, it would fail in the closed position and cause overheating. That response does not address my problem of the thermostat failing to close enough to keep the engine up to proper temps. for complete combustion. As I live just north of Tucson, it will soon be warm enough to get my engine up to 3 bars. How about the ST 1300's of 2003 vintage who live in much cooler climes? Do they run around all this season with only 1 or 2 bars showing? If not, perhaps Honda of North America has us in what I used to call a "Snow Job".

[georgeorge]

I think it is a snow job. I have heard of a few people on misc boards with st1300s that had their thermostats fail and they (correct me someone if I"m wrong) always fail open. My bike warms up to 3 bars and stays there...always. After it's warmed up I have never seen anything but 3 bars. I live in CT and have riden in as high as 95 degrees and as low as 27 degrees.

Brian

[Bones]

I'm in Massachusetts and my experience is just like Brian's -- 3 bars once it's warmed up, no matter what the outside temperature is.

[georgeorge]

Actually Charlie most Thermostats are fail-closed. Fail safe or fail-open are the more expensive, but I think that Honda uses the fail safe thermostat.

Brian

[NormanPCN]

Every abnormal thermostat report I have read about is fail/stuck open too much and thus running too cool. Sounds like a typical, ain't no problem because we do not want to fix it snow job.

[Mellow]

Mine was just replaced last week and the Service manager at Cycle Center of Denton, TX told me it was stuck open.

Before, I had 3 bars all the time... All of a sudden, during some cold weather, below 50 degrees, I noticed there were only 2 bars... in very cold weather, 30ish degrees there was 1 bar and sometimes no bars.

When I called the Honda Service phone line they said they knew nothing of this.

How do you know if your thermostat is stuck open?
- Your bike takes a long time to warm up to 3 bars, if ever
- Once you get moving the bars reduce from 3 to 2 or 1 etc.

The first dealer I took the bike to, Plano Honda of Texas, said they tested everything and couldn't find anything wrong. I said "did you test the thermostat?" and they said "we don't have enough evidence to justify utilizing that much labor to take all the plastic off to test it".

If it weren't for my coolant leak and an understandable dealer I probably would have had to replace it myself as I was prepared to. I still have the thermostat and o-ring in case anyone else needs it.

So, there's one documented case where it was stuck open. I think they are just going to address these as they happen. A stuck open thermostat won't matter during the summer as the fans will kick in and during the winter a colder motor isn't as bad as an overheated one... Still not good but not as bad.

When it happens, it will be all of a sudden with no warning. You won't be stranded by any means and if the temps get back into the 60's or higher the bars will go back to 3...

Hope that helps a little.

[basco]

I have the same thing happen to my bike. Bars dont get to three only rarely and on 50deg days or warmer. I got the bike at the shop for recalls and to check on the thermostat and a possilble trade in on a red one.

[NormanPCN]

Why trade in to get a red one? Why not just paint.

[basco]

Why trade in to get a red one? Why not just paint.

Paint with sanding in some areas, 32k miles, motorized screen, new tires, valve adjustment. I might as well get a new one. I did make some mistakes on the bike that I probably wont on the new one. Like mounting stuff. No more holes unless I can't help it. Maybe a powerlet on the right side but thats it.