New bike and temperature

Hi ST riders

Finally brought me a st1100.
A 1991, but here in Denmark bikes are expensive (tax) and people take good care of them



On the way home (hundreds of miles at high speed) I noticed the temperature does not get above 1/3.



Is that normal ? I suspect the thermostat might be stuck open.

Thanks and have a good season

That is a great looking bike. Low miles also. That gauge looks about normal when riding.

Thanks for the replies and the nice comment. I always worry too much

Even well taken care of, I would pop the side tupperware off to get the turtle top off and have a CLOSE look at the overflow hose where it attaches to therm. housing, looking for a split in hose. If coolant level in overflow tank is suspect high, then that hose definitely has a split in it. Don't know what the outside ambient temps were when you snapped the pic, but if in the mid 70's, and just cruisin', that indicater needle is bout in the right area. The cooling fan on our early 1100's, with everthing correct as it should be, will come on just PRIOR the halfway mark, not after the halfway mark as stated(that bike unknowingly has a gradual cooling related issue starting).
So as not to worry, the temp gauge will vary a needle width or so depending on outside temp. of area your riding through. If that needle temp. starts varying substantually with no drastic outside temp drastic changes, other than it rising a bit pulling a grade or similar added load, then you may wanna look things over a bit for a coolant related issue

If you remove the left hand service cover from the fairing, the one that covers the left cylinder heads, you will see a sensor on the radiator about half way down.....

Take the wire off, connect this wire to the battery negative with a long piece of suitable wire and turn the ignition on.... the cooling fan will run....

Do this before you allow the bike to run to test the fan for real, because if it isn't working, you could do damage through overheating the engine at standstill....... and waiting for the fan to kick in....

Once you know the fan works you can allow the engine to idle until the fan turns on and see where the gauge sits then.

My 1998 runs the same temps yours does, same pattern. I just replaced the coolant return hose. It wasn't expensive, and when I took the old one off, the hose near the radiator cap had surface cracks. Not all the way through, but on it's way. This is an easy preventive maintenance item, and I highly recommend you do it.

Lucille has been doing the same on the gauge for as long as I've had her. Ride it like you stole it!!!

ubuntufan said:

On the way home (hundreds of miles at high speed) I noticed the temperature does not get above 1/3.

Click to expand...

Looks OK to me, only when going below 60kph the radiator lacks of airflow, thus temps raise so the fan will kick in.
With the temp needle at a 1210hrs position the fan cycles ON, when it turns OFF the needle will be at ~1150hrs...

When riding m/ways or rural roads near 0?C, the needle even won't go into the white field from the left...

I might just mention, too, to check the connection at the overflow tank. I found the cap with the molded line in it was plugged. And as a tip, should you want/need to clean that tank, use some BB's and cleaning solution to shake in there and it'll clean up pretty good.


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You picked a good ride and welcome!

Thanks ST veterans :bow1:

I did check the overflow connection, and guess what, the hose had a bulb and was about to crack.

Ah, good deal! Great catch!


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