Help needed- newbie- temp gage

Joined
May 5, 2017
Messages
24
Location
Bristol
Hi all picked my ST1100 up on Thursday but today is the first time i have taken it for a run. Did about 50 miles and was out for about an hour. Although the bike seems to be running fine (but what do i know) the temp gage barely moved (if it moved at all) It definitely never want out of the white. It is pretty chilly out today but there is no frost or anything like that.
Is this normal? If not whats broke? It passed an MOT on Wednesday. If it is in need of a 'look at' can anyone recommend someone near Bristol, Uk?
Paul H.
 
Joined
Feb 25, 2016
Messages
4,759
Location
Northumberland UK
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VStrom 650
Paul,
I would think the thermostat may be stuck open or of course it could be a faulty gauge. Have you checked the fluid levels?
Hope it helps.
Upt'North.
 
Joined
Jun 3, 2006
Messages
3,512
Location
British Columbia
Bike
2021 RE Meteor 350
If the ambient temperature is quite cool, you can expect the needle to remain close to the cold end of the scale, however, if you let it sit and idle, the gauge should rise to near the 12:00 position and the fan will come on shortly after that. If the needle doesn't rise much, then you likely have a thermostat stuck open - the only reason an engine will run cold.
 
Joined
Feb 25, 2016
Messages
4,759
Location
Northumberland UK
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VStrom 650
Paul,
In normal UK temperatures mine stays at about a third up the scale unless in traffic when it will rise to 12 o'clock before the fan kicks in.
Upt'North.
 

Dave.David

Rider
Joined
Dec 9, 2016
Messages
716
Location
SB California USA
Bike
05,ST1300-04VTX1800R
STOC #
8938
So if it is sticking is that a replace?
P
Definitely should be replaced if sticking. But don't forget to check the sending unit, wire, and gauge. Start by taking the wire off the sending unit and grounding it with the key on. The gauge should quickly show full hot temperature. If not the problem is in the wire or the gauge. If showing full hot the problem is in the sending unit or the thermostat.
This is where I would start.
 
Joined
Sep 10, 2011
Messages
2,211
Location
West Michigan
Bike
'98 ST1100
STOC #
8470
Let the bike run at about 2000 RPM on the center stand. The temp gauge reading should start to climb. When it reaches about the 12 o'clock position, the cooling fan should turn on and after a minute, the temp should decrease and then the fan should turn off.

If the gauge doesn't start to climb with the bike running on the center stand, you probably have a thermostat that is stuck open.

A Stant 13868 automotive thermostat ( or equivalent ) and a Stant 11233 radiator cap fits and they are cheaper than the Honda OEM parts. I have been using a Stant for the last 45K miles.
 
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Joined
Sep 10, 2011
Messages
2,211
Location
West Michigan
Bike
'98 ST1100
STOC #
8470
Mr. Bush - Did I say I have been using the SAME Stant 13868 thermostat ? NO , I didn't !! I'm on my second Stant thermostat. When I rebuilt my water pump @ 85 K miles, I installed a new thermostat - just to be on the safe side .......along with installing an extra camshaft timing belt guide plate - better than stock, now.

Actually, I'm thinking of installing a 190 degree Stant to see if my gas mileage will increase. :)
 
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Paul_H_PAN
Joined
May 5, 2017
Messages
24
Location
Bristol
OK so i have run it around quite a bit now. If i let it stand it quickly goes up to around just under half way and the fan turns on. It's still barely going out of the white ever once i'm riding around though? So pull up for about 3-4 mins it goes up pull away t get back to just on the white line.
Is that all ok or is it still faulty?
P
 

Slydynbye

Will ride for Pie
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Sep 3, 2007
Messages
1,596
Location
Fremont, California
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2000 ABSII
STOC #
7331
A Stant 13868 automotive thermostat ( or equivalent ) and a Stant 11233 radiator cap fits and they are cheaper than the Honda OEM parts. I have been using a Stant for the last 45K miles.
I have been thinking the same thing, the Stant seems to run a little cooler than OEM on 2 different ST1100s and possibly affecting mileage.
 
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Paul_H_PAN
Joined
May 5, 2017
Messages
24
Location
Bristol
Ok so i finally purchased a proper Honda thermostat came all the way form California! Fitted it and the old thermostat was indeed seized open, so I got all excited fitted the new one and replaced the coolant, fired her up- all well. Gauge went up and the fan kicked in nicely. Take it out on the road..... its exactly the same as the broken one! Temp gage hardly goes out of the white cold unless i pull up and then it slowly creeps up and then goes back! Hmmmmm
Still at least i know it has a nice clean working thermostat now.
 

Dave.David

Rider
Joined
Dec 9, 2016
Messages
716
Location
SB California USA
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05,ST1300-04VTX1800R
STOC #
8938
It's rare but you could have gotten a bad thermostat. And of course you want to make sure the bleeder hole is facing up.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 
Joined
Mar 13, 2012
Messages
5,046
Location
soCal
Bike
'97 ST1100
STOC #
687
I can think of a few things to check:

1. Its possible your temp sending unit in the thermostat housing is going a little out of spec, its fairly easy to pull out and test in a pan of boiling water (check at various temps along the way).
2. since the temp sensor resistance increases at colder temperatures, perhaps you have a little corrosion inline that is adding to the resistance and making the needle point lower than it should. Check the connector on the sensor for any corrosion.
3. Its also possible that the contact of the sensor with the ground supplied by the t-stat housing isn't very good. There's pipe thread compound on those threads, if there's too much then that could compromise the ground contact. A bad ground would also increase resistance, making the gauge point lower, but I think this one is probably more of a longshot.
4. check that the t-stat housing itself is tightly mounted to the frame to complete the ground connection, although that was probably just verified with the t-stat swap.

Or maybe the gauge itself has gone a little off. These bikes are getting old and some of the analog circuitry is starting to drift.

Mine has the symptom where the temp gauge stays low for normal riding, then when I pull up to a stoplight on a hot day the needle will move very quickly from the normal position to 12 o'clock. Then once it goes to 12 o'clock its a much, much longer wait for the fan to finally kick in, and all works normally there. I've replaced the t-stat and the temp sender unit, and triple checked everything else, and it hasn't changed, so I just live with it. It seems to have gotten hyper-sensitive to a very small temperature change for some reason.

So, you're not the only one with a weird acting gauge, check the stuff above and if you don't find any explanation don't worry about it.
 
Joined
May 27, 2013
Messages
162
Location
Newmarket, Ontario north of Toronto
Bike
1999 ST1100
Your temp gauge seems to be responding exactly as mine. Your thermo-sensing unit (forgot the correct name for this piece) is obviously working as it sends a current to your cooling fan to kick in and that's the most important part of this scenario. I suspect that when you ride in warmer weather you will indeed see more "12 O'Clock" action/positioning of your gauge and more cooling fan time. When I picked up my bike I ran it mostly on the highway and the temp gauge never went up...also the fan never came on (just like yours)...however one hot day when I was in traffic it climbed above the 12 O'Clock position and no fan came on and that's when I realized I had a problem (Thermo-Sensor...or whatever you call it). Replaced that (and also the thermostat) and after 3 years the gauge still reacts just like yours. Just enjoy the ride!
 
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