Coolant Temperature Gauge

[RacinRay]

While out riding my '16 ES today I noticed that the coolant temperature display reading was fluctuating from 145 to 180. Every time the display hit the 180s it would drop instantly to between 145 and 150. Then slowly raises again to the 170s and 180s. This cycle takes 20 to 30 seconds and repeats continuously.

If I turn the motor off the display will rise to the 180s and hold steady.

Of note I just got the bike back from the dealer who replaced the left side fairing an mirror.

Thoughts?

 

[RacinRay]

While out riding my '16 ES today I noticed that the coolant temperature display reading was fluctuating from 145 to 180. Every time the display hit the 180s it would drop instantly to between 145 and 150. Then slowly raises again to the 170s and 180s. This cycle takes 20 to 30 seconds and repeats continuously.

If I turn the motor off the display will rise to the 180s and hold steady.

Of note I just got the bike back from the dealer who replaced the left side fairing an mirror.

Thoughts?

 

[escapefjrtist]

Documented many times, completely normal.

--G

 

[RacinRay]

Oh no! I not only double posted from my phone, but my Google search of the forum failed to find a common problem. Doh! Sorry folks.

 

[RacinRay]

Okay, I apologize again but I've searched and searched and cannot find a thread on this well documented problem. Can someone please help point me in the right direction. Thanks.

 

[Ignacio]

Okay, I apologize again but I've searched and searched and cannot find a thread on this well documented problem.

What specifically were you searching on? Let us help you find it.

 

[PhilJet09]

Double-double posting is hilarious...regardless of what the mods think!

Sorry Ray.

 

[RacinRay]

Specifically, I searched:

Gen 3 Temperature Gauge

Temperature display problems

Temperature display fluctuating

Temperature Gauge fluctuating

Coolant temperature fluctuating

Coolant temperature display

And other combinations.

If it's well documented, I don't know what it's listed under.

 

[dcarver]

Ok, so I'll provide another data point. My 2014 temp gauge sees 180 to 235 degrees F. Surprised to see the >230F numbers. No boil over.

 

[RaYzerman19]

The way the cooling system is designed, there are going to be fluctuations..... Gen1/2 had buffered displays. Gen3 is showing every fluctuation...... move that off your primary display and put it on "consult as needed".

https://www.fjrforum.com/forum//index.php/topic/166961-temperature-readings-on-2015-fjr/?hl=%2Bcoolant+%2Btemperature&do=findComment&comment=1291627

 

[RacinRay]

Thank you all! I guess I just noticed the phenomenon this weekend because in warmer weather I don't display the coolant temperature.

I will "ride more and worry less!"

 

[Wemi]

Thank you all! I guess I just noticed the phenomenon this weekend because in warmer weather I don't display the coolant temperature. I will "ride more and worry less!"

The issue you describe is one of thermostat action. The bike has a 180 degree thermostat. So, once it reaches that temp, it opens up and the cooler radiator fluid enters the system lowering the temperature, in the process closing the thermostat again, causing the temperature to rise again and so on. This frequency will vary depending on your riding environment. Here in SoCal the running temp is around 164 and it will go up to 230 in town, where the fan cuts in and lowers it again and with increasing speed will steady out again around 164. The lower the running temp the more frequent the cycling as the thermostat will keep closing thereby raising the temperature. Most of this undesirable cycling is caused by the required emission controls. A cooler running bike is much better for the life of the engine but, alas it throws out more unburned fuel or pollution. I have noticed that the exhaust type also has an effect on the running temperature. I had a new set of Yoshi OEM cans installed on my 2015ES and the bike ran around 153 degrees. That was fine however the cycling up and down increased significantly and actually became annoying. I removed and sold the cans and put the stock exhaust back on and so.ved that issue.

 

[El Toro Joe]

Ok, so I'll provide another data point. My 2014 temp gauge sees 180 to 235 degrees F. Surprised to see the >230F numbers. No boil over.

My 16 does the same...up to around 230 or so, before the fans kick on...that was with 82 degee temps today.

 

[N4HHE]

If ever you have an automotive thermostat in hand try boiling a pot of water and after boil throw the thermostat in. You will witness it opening over the next several seconds. Move it from the boiling water to room temperature water. It closes but slower than it opens.

 

[RacinRay]

I thought it might just be the thermostat working but the cycle was as o quick, every 25 - 30 seconds. I didn't realize it could cycle so fast.