I am trying to figure out the correct running temperature of my bike (1995 F3), and am getting a bit of conflicting information - and I cannot locate anywhere in the manual(s) that specifies proper operating temperature range. My bike is reporting 190-205F when riding and 205-215F when sitting in dead traffic. Both ranges are in 85F degree weather. And yes, I know the specific temperatures because I have the F4i gauges with the 900 thermo sensor installed.

The following two posts indicate conflicting reports, so anyone got feedback on what the operating range is for the F3?

rangerbrown says (ORIG POST) that his bike runs 160-180F with the fan coming on at ~170F.

johnnyx says (ORIG POST) the fan should come on at ~220F.

Anyone know the right answer here??

 

Yours is normal.This era Honda (last of the carbed bikes) runs a wee-bit warmer than the rest.

 

I was told in automotive school that proper engine temp range is 210 degrees. I am sure diff engines vary, but I suppose that is the typical temp.

 

180/190 degF is optimum,but the street is not a controlled environment.Therefore the bike going to 210-220 is not going to hurt it,so long as it doesn't stay there.

I think the fan should come on @ 200,but that's just me.

What you're seeing on your bike is a wee-bit over normal.If I were you,I'd flush the radiator using a 50/50 mix of distilled white vinegar and distilled water.DO NOT use tap water,EVER.Re-install and then manually burp the radiator.Replace radiator cap with 1.1kpa ND cap.All this will cost you 20 dollars and 1 1/2 hrs of time.

Holla back.

 

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180 (needle at 50%) is typical for highway. Traffic will get you at around 215 which will kick the fan on. 220 degrees puts your needle at about 3/4 which is fine. Worry when you get red, because that means you are getting to 240+. If your gauge isn't in the red, its fine and will not change anything or effect how long your bike lives.

 

First off, thank you guys for the assistance. Kjohnson, your advice is particularly helpful as I assume it's from your riding experiences. More info and questions below...

So I was reading in the "General Information" sections of two different manuals about cooling system operating temperatures and what should come on and when. It appears that the Themostat should begin to open 176-184F and be fully open at 203F. So in a controlled environment, it looks like the bike is trying to keep itself under ~205F.


According to the PDF manual available from stephygee (on page 1-12), the cooling fan switch should start to close (turning fan on) between 208-216F.


Couple of questions on the process here ... 1) When you say flush with dist. vinegar/h20, do you mean to just let it run through from filler to drain, or do you mean to plug the drain and let it circulate for a few minutes with the bike running? 2) What does flushing with the vinegar do for the radiator? Is it some sort of cleanser in this case? 3) What will a higher-pressure radiator cap do for the bike's cooling system?


Thanks again for all the info!

 

I race these things too,with WERA.Over time I've seen the entire range of conditions that these bikes are in.

Vinegar is a cleansing agent,ridding the radiator of the calcium and scale that has built up over time when dumbasses use tap water in the radiator.

Remove the radiator from the bike when doing this.

High pressure cap is complete overkill on a stock streetbike.

Prolly wouldn't hurt to go ahead and replace the thermostat.Only use OEM.

 

Thanks for clearing that up! I really appreciate the assistance. One final question, and I apologize if I am just misunderstanding something here...

You mentioned I might want to replace the radiator cap with a 1.1kpa ND cap - which I thought was a higher pressure cap .. was I incorrect in my assumption? And what would the difference between 1.1kpa cap and the stock cap be?

Thanks again!