I found out I don't even have a thermostat in between my engine block and through the hose into the radiator. I am not sure if the previous owner knew or not.

Is this why my temp gauge keeps sitting right at/below redline? I have never actually gotten a temp gun and read my engine block. What is the normal operating temperature?

Thanks.

 

Purpose of the thermostat is to allow the engine to quickly acheive normal operating temp. The tolerances of an engine are actually too tight until the parts expand as they reach the designed operating temperature. After that is achieved the termostat is open and has no effect on the operation of the bike. They are designed mostly for the colder climate conditions. In the bad old days, people would actually pull the thermostat in the summer to remove the restriction and enhance summer performance. Hence, only affects the first few minutes of operation, after that it is always open.

The guage reading could be a bad sensor or a good sensor and blockage/air in the system. If you haven't changed/fliushed the coolant in a long time, never hurts to start there. Also check for bent fins and/or blockage on the radiator itself.

Another, longer, shot is that the engine is running rich, thus enhancing temps.

Ern

 

I know there is no air or blockage in the cooling system, and my radiator is good. It still holds pressure. While riding I can feel the tube coming out of the engine right side and it is much much hotter than the tube coming out of the bottom of the left side of the radiator. And about the thermostat- If that is all it is for, do I need to get one? I have had the bike now going on 4 years and it hasn't had one in the whole time.

So, where does the temperature gauge get it's reading from? I am confused. And what is the safe range of operation temperature. I won't have access to a temperature gun for a couple days, but I would like to know. I may not be overheating at all.

And wouldn't the engine have to run lean, more air, less fuel, for it to run hotter? Not rich?

Thanks for the help.

 

Is your fan on while your temp gauge is at/near redline? My bike was like yours when I first got it because the fan wouldn't turn on. After fixing the problem with the wiring of the fan, it would turn on midway between high and low.

 

I am having a similar issue, when i ride the bike hard, it will just keep on climbing into red,

Replacing the thermostat today to see if that will resolve my issue.

you may be OK without a thermostat, but there is a reason every liquid cooled vehicle on the planet comes with one... I guarantee every manufacturer would drop them and save the $2.50 it costs if they could.

have you tried changing your coolant?

 

Beware of removing the thermostat. Often this will result in the coolant passing through the engine too quickly, and it won't scavenge enough heat. You can actually overheat your engine doing this.

 

This is not an accurate description of how an engine thermostat works, no offence intended. An engines thermostat is designed to restrict flow into the radiator portion of the cooling system. Stating that it is initally closed is correct. It then gradually opens with the increase in temperature. That being said, a thermostat is NEVER constantly in the open position. It opens and closes depending on the temperature of the coolant, when the engine cools down to about mid operating temp, the thermostat is only about half way open, allowing more coolant to flow back directly through the engine and keeping the coolant in the radiator somewhat cooler so that if the engine does start to overheat it can fully open and allow some of the hotter coolant into the radiator to cool and the coolant in the radiator to cool the engine. If you do not have this in the system, it will not be able to regulate the coolant and keep it in the radiator long enough which in turn will not allow the radiator to cool it properly.

Now that we have the proper thermostat operation out of the way, Yes if you are running LEAN you will see hotter engine temperatures.

Also, are you doing mostly city driving, or highway? If you are sitting in traffic on a hot day you will see your temperature sit right at the line to overheating even with the fan on, but if you are on the highway cruising along, it should be right aound the middle.

Its also possible you may have a partially blocked radiator, with the bike at operating temperature just touch the radiator fins and see if any portion of the radiator is still cool, this would indicate that you have a blockage.

Not to insult your intelligence, but you did remove the thermostat housing and check for a thermostat? Or did you just remove the hose and peek inside?

 

Ok that is much more clear. Thank you for the accurate description of a thermostat and what it is doing in our bikes. I have a feeling my bike IS just passing coolant through too quickly, and not allowing any coolant to grab heat from my cylinders while it passes through. Are thermostats the sort of thing you buy to fit both cars and other vehicles, or is it a very model specific thing.

No offense taken- I took the housing off. There was nothing there at all. And ya, I have done the radiator flush, and am running 50 water/ 40 coolant/ 10 water wetter. I will check for "cool spots" on my radiator the next time I run it and see if I may have any partial blockage. Oh and ya, to the other question- My fan does turn on when it gets hot.

My other questions remain though: Where does the temperature setting on our dash get its reading from? Is it the sensor right by the cam chain tensioner, that goes through into where the thermostat would be? And what is the safe range of operating temperature? I searched but found a lot of different answers. And if I do use a temperature gun to find out if I actually AM overheating, should I read it off the cylinders where the pistons are, or lower on the engine block or what?

Thanks again. I really want to get this heat issue sorted out. I know it is not lean. It is really bugging me not to be able to go on long rides.

 

Ok awesome, are they model specific? Yes and No. One thermostat may fit a variety of different bikes, but you need to order the proper one for your bike, they are not that expensive, your local honda dealer can fix you up. Your Temp Sending Unit (Temp Sensor) is the sensor located right by the thermostat housing.

If you are running watter wetter you definetly shouldn't be overheating. Get yourself a thermostat and then do the radiator check and go from there.

Normal Operating temp will varry between 190 and 220 Degress F. Anything much higher than that is a little hot. Remember, water boils at 212. I would put the temp gun right on the coolant hose.

 

Ok, if the temperature sending unit is in the thermostat housing (I can see the *** sticking through and touch it), then it must be reading coolant temperature leaving the engine. My initial thought of what a thermostat would do, is slow my coolant down to let it absorb more heat from the cylinders, before passing into the radiator. But if my coolant NOW, is just passing through unrestricted at all times, not allowing heat to be taken off the cylinders, shouldn't my temperature gauge be reading low because my coolant would be colder than if it were doing it's job?

Or am I way off, and the temperature sending unit actually reads the temperature of the metal?

Thanks for the info/help.