Coolant system, Fork Oil

snowworks

snowworks

Joined
Oct 9, 2022
Messages
38
Age
65
Location
Livonia MI
This week in Michigan I got my 93 ST legal and have put on about 110 miles. Still working out the bugs.. MY question where should the temp gauge be when running on the road?? In the middle or a little left or right of center?? Today it was cool low 60's Riding around on the back roads all is well. Then I took off on the Highway and the temp gauge dropped to just above the second white mark. To me I have a stuck open thermostat. Where the picture shows. Also what is the temp that the thermostat opens for reference. 180, 190?? Second I was thinking I should change the fork oil. My Clymer manual I do not see about changing the oil. Just rebuild the forks. I have done older cycles. Can I change the oil like I am used to?? Pull the drain plug. Take the weight off the forks. Loosen the top clamp bolt, then take out the top plug. Add the proper amount of fork oil per side.. I see the side to side are different.. The plug is what I have circled. No leaks that I see, but maybe there is no oil..?? STcoolantT.jpgSTforkDplug.jpg
 
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Your temperature gauge is about right, perhaps a little low and those are your fork oil drain plugs in the photo. My dealer only ever used 10w, but it was far too stiff for me - try 7.5w or 5w.
My records show the thermostat at ..80*C~84*C (176*F~180*F).
I also have temperature sensor info.......
50*C/122*F = 130>180 ohms - v. cold
80*C/176*F = 45>60 ohms - normal range
120*C/248*F = 10>20 ohms - v. hot
Substituting a 50 ohm resistor in place of the sensor should get about half scale on the gauge.
 
My temp gauge stays very cool too, i think its quite normal. It only really comes up to centre when stopped for a while. I tested my thermostat on the hob, it was open at 95 degrees C
 
Somewhere in this site are the fork oil level measurements. Right and left are different. You can carefully measure the oil level to the top of the tube and or you can take a measurement before you start. I used synthetic atf, it's about 7w and it has more anti wear properties. Rode much better. Your temp gauge it perfect, when it's hot out it will get a bit higher. The cooling fan should kick on at about 1 o'clock. :guages1:
 
IIRC, the Honda Service Manual contains the fork oil specs, in the specifications tables at the front of the book. Are those tables not in the Clymer version?

You never get all the oil out from just opening the drain plugs, so refilling with the spec amount will result in overfilling. Best to remove the forks, invert them and pump several times. Then, measuring the oil height with the spring out will insure proper oil level.

Read this article for guidance.

Progressive Springs installation ( ST1100 ) **

Progressive Springs installation ( ST1100 ) **
www.st-riders.net
 
Bush said:
IIRC, the Honda Service Manual contains the fork oil specs, in the specifications tables at the front of the book. Are those tables not in the Clymer version?

You never get all the oil out from just opening the drain plugs, so refilling with the spec amount will result in overfilling. Best to remove the forks, invert them and pump several times. Then, measuring the oil height with the spring out will insure proper oil level.

Read this article for guidance.

Progressive Springs installation ( ST1100 ) **

Progressive Springs installation ( ST1100 ) **
www.st-riders.net
Click to expand...
Thanks Bush for the reply. The oil amount in that is different for each side is in the Clymer manual. I was thinking of just doing a oil change on the forks just to see if there is oil in the forks. Then as I put some miles on it I can see if the forks seals leak. Then I can get the parts and do it all at one time..
 
snowworks said:
This week in Michigan I got my 93 ST legal and have put on about 110 miles. Still working out the bugs.. MY question where should the temp gauge be when running on the road?? In the middle or a little left or right of center?? Today it was cool low 60's Riding around on the back roads all is well. Then I took off on the Highway and the temp gauge dropped to just above the second white mark. To me I have a stuck open thermostat. Where the picture shows. Also what is the temp that the thermostat opens for reference. 180, 190?? Second I was thinking I should change the fork oil. My Clymer manual I do not see about changing the oil. Just rebuild the forks. I have done older cycles. Can I change the oil like I am used to?? Pull the drain plug. Take the weight off the forks. Loosen the top clamp bolt, then take out the top plug. Add the proper amount of fork oil per side.. I see the side to side are different.. The plug is what I have circled. No leaks that I see, but maybe there is no oil..?? View attachment 333665View attachment 333667
Click to expand...
My 1991 has always run low, like your photo when riding. It creeps up to about 1/3 scale if I catch a long light.
 
All four of mine stay at about 1/8-/4 after warmup unless stopped in traffic then they can get up to about 1/8 from the right before the fan kicks in.
If you decide to change the stat, there are several aftermarkets that work well and are cheaper than Mother Honda.
You will need the gasket and I recommend Honda HT sealant.
 
I likely would not change the T-stat if it’s running fine (not too cold and not too hot)- from new, my 2000 has always run just above the second mark on the left, so to me that’s the normal mark- if it’s on the road and for some reason running hotter, then I’m concerned. I ran a bypass switch on both STs so if I’m sitting in traffic for a longer time, I don’t need to wait til the bike gets hotter, just push the switch and force the fans on (but they work as well if I let the bike get hotter).
 
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