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Radiator fan running after short rides

JBIZZ

2016
CBR650F
Aug 2, 2024
Riding Since
2024
hi everyone,
I recently purchased a 2016 CBR650 F and continue to feel as if the bike is hotter then it should be.
I have checked oil and coolant levels (All are fine) and no indicator lights on the dash but I
Went for a 15 minute ride the other day (in 4 degree weather,not in traffic for very long) and with the keys switched to accessory's on the fan would continue to run.
this has only started to happen this past week. not sure if this is normal or not but just haven't noticed it in the 4 months I have owned the bike.
Thanks any help would be greatly appreciated
 

Brian C.

2021
CBR650R ABS
Nov 26, 2021
Northwich
Riding Since
2021
I don't believe this is something to worry about with no lights on, or warnings.
I have a 2021 and very often when i park up after a ride and leave the ignition on, the fans will cut in. Remember after riding your water pump is no longer running and the residual heat from the engine is still being absorbed by the coolant, so its not concerning to me at least that the Bike will attempt to dissipate this heat by kicking in the fans.
If your coolant levels are right and the bike does not show any signs of overheating i would enjoy the bike and not worry about it.
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
Riding Since
1993
Check the radiator is clear and clean.

Assuming you really mean 4c (winter down under right?) I'd be surprised if the fan was needed.

It could be a sign of a stuck thermostat, meaning the coolant isn't going through the rad as it should be.

Start with the simple stuff though. Also have a read of the service manual.. Specifically the section on the cooling system for checks and procedures. The system isn't that complex.

J
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
Start with a fill coolant flush if you don't know when it was done last. Until you have a baseline, you are just guessing because it could be nothing or the start of something big.
 

enshiu

2016
CB650F ABS
Mar 30, 2023
Riding Since
2021
check the rad fan if it isnt stuck because of mud or dirt.
Check thermostat and fuse of the fan
 

papajim93

2024
CBR650R ABS
Mar 20, 2025
Riding Since
2024
I think this is normal. I was also paranoid about it when I first bought the bike and asked many other riders with the same bike. All said it was normal and their bikes also do the same. The only annoying part is that if I ride somewhere and I stop for a smoke or go to a shop to buy something I have to leave the key in the ignition till the fan stops running. Then I take me key and go. Smoking solved this one, since it doesn't take longer that a cigarette 😅😅😅
 
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