Strange cooling issue
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From: NYC
Strange cooling issue
Wow long time since I've posted. Busy summer of racing and dirtbike riding.
So the ole' hawk is acting normally as far as warm up and riding around town, it just doesn't cool itself down the way it used to when its hot from traffic and I get moving over 50mph. It doesn't cool off much below 195F.
I suspect a thermostat issue so am getting a replacement but any guesses. ??
So the ole' hawk is acting normally as far as warm up and riding around town, it just doesn't cool itself down the way it used to when its hot from traffic and I get moving over 50mph. It doesn't cool off much below 195F.
I suspect a thermostat issue so am getting a replacement but any guesses. ??
evil man of nothing
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Joined: Jan 2006
Posts: 4,516
From: Boynton Beach, FL
May seem obvious but is the fan turning on normally (I believe it's around 215)? My first (also the only brand new vehicle I've ever owned) Superhawk, a '98, overheated with about 60 miles on it the day I took it out of the crate because the fan temp switch was bad and never turned the fan on in traffic.
Last edited by captainchaos; Sep 18, 2019 at 07:11 PM.
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From: NYC
Yes fan comes on as it should. On my CBR dash I have it wired in so that a red FI light comes on the dash when the fan is on so I can always know its working.
It does ok using the fan but not with natural air flow. I took a highway ride upstate and the motor stayed around 190 to 200F even at highway speeds which seems high to me.
It does ok using the fan but not with natural air flow. I took a highway ride upstate and the motor stayed around 190 to 200F even at highway speeds which seems high to me.
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From: Kempner, TX
Yes fan comes on as it should. On my CBR dash I have it wired in so that a red FI light comes on the dash when the fan is on so I can always know its working.
It does ok using the fan but not with natural air flow. I took a highway ride upstate and the motor stayed around 190 to 200F even at highway speeds which seems high to me.
It does ok using the fan but not with natural air flow. I took a highway ride upstate and the motor stayed around 190 to 200F even at highway speeds which seems high to me.
Have you confirmed the temp reading is accurate?
I assume you have looked to make sure no animal has built a nest blocking air flow, no rag was left stuffed next to radiator, piece of cardboard is there that you put in last winter to get engine temps up on freezing days?
VTR virgin
Superstock
Joined: Mar 2015
Posts: 447
From: Auckland, New Zealand
You can externally check the condition of a thermostat based on the way the bike warms up from cold. A correctly working thermostat stays closed until the coolant in the engine block reaches the opening point, then starts letting the hot coolant out to the radiator. So your radiator should stay practically stone cold for a few minutes and then suddenly get too hot to touch. On the other hand a stuck-open thermostat will let coolant flow to the radiators at all times, so you should start to feel the radiators gently heating almost as soon as you start the engine.
A part-open thermostat would explain why the heat while running stays high as the normal fast flow to the radiators from higher revs would not be able to pass. When you are at idle the flow would be less restricted and so the system would appear to be cooling "normally".
A part-open thermostat would explain why the heat while running stays high as the normal fast flow to the radiators from higher revs would not be able to pass. When you are at idle the flow would be less restricted and so the system would appear to be cooling "normally".
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From: NYC
Ok yes so that is what I was thinking. I figured stuck closed since in slow traffic the difference is negligible but at high revs the volume is too little to do the job.
Will also check for obstructions but I ride every day so seems unlikely. Ambient was maybe 80s when I made the upstate trip but its been the same deal since then with some temps down in the 60 recently.
I wonder if there is a useable version at a laps that would work and be way cheaper. I know there are other parts that crossover to the car world.
Will also check for obstructions but I ride every day so seems unlikely. Ambient was maybe 80s when I made the upstate trip but its been the same deal since then with some temps down in the 60 recently.
I wonder if there is a useable version at a laps that would work and be way cheaper. I know there are other parts that crossover to the car world.
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From: NYC
So new thermostat is in today and it seems like its cooling better.
Tested old thermo in hot water and it didn't open as soon as it should and not til almost 200F which may explain the issue.
I believe this solved the issue. The coolant was crystal clean (of course).
Tested old thermo in hot water and it didn't open as soon as it should and not til almost 200F which may explain the issue.
I believe this solved the issue. The coolant was crystal clean (of course).
Last edited by smokinjoe73; Oct 13, 2019 at 07:28 AM.
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