er5 fan running after switching off ???

[littlecat]

Chiras 2002 er5 , the bike seems to be running fine, has just had a full oil and filter change, and flew through MOT with no advisories, but after a run to matlock on sunday , ( last part of which was stuck in slow traffic) noticed the fan running for a while after shutting off the engine.

is this normal ? or should I be checking something ??

[Stu]

Its normal

[Fozzie]

I have a 2009 CBR600RR that does it, and thats more teched up!

Basically when you switch off the engine, the top end has a lot of heat built up, which when the engine stops so does the pump pushing coolant around. So it actually heats up a bit after turning off as nothing is there to regulate the remaining energy stored. And it trips the sensor as a result!

So it's all good

[Stu]

I have a 2009 CBR600RR that does it, and thats more teched up!

Basically when you switch off the engine, the top end has a lot of heat built up, which when the engine stops so does the pump pushing coolant around. So it actually heats up a bit after turning off as nothing is there to regulate the remaining energy stored. And it trips the sensor as a result!

So it's all good

 

That's a pretty good theory foz but the sensor is in the rad and not the top of the engine

It will stop when the temp of the rad drops and the sensor is satisfied

[Fozzie]

Ah, to adjust that theory slightly

When the engine is running, coolant flow to keep it cool by picking up heat and going to the radiator where it expels it, cools down and circulates around the system again.

The explosions in the cylinder of fuel is a good few hundred degrees in temperature! You switch the engine off, the heat in the cylinder walls etc dissipates, and the coolant now no longer flowing does not cool off via the radiator. So instead the coolant in the cylinder head will get VERY hot and the pressure will increase. Heat spreads through the system, which has no air or circulation to keep it cool and it causes a heating effect for a minute or so after the bike has been switched off. During warm weather the ambient temperature isn't enough to cool the engine quick enough so the fan is tripped.

Is this enough detail Mr Stu?

[Grumpy Old Git]

It just does it - OK?

Simples!!!

[Chrissb6]

I have a 2009 CBR600RR that does it, and thats more teched up!

Basically when you switch off the engine, the top end has a lot of heat built up, which when the engine stops so does the pump pushing coolant around. So it actually heats up a bit after turning off as nothing is there to regulate the remaining energy stored. And it trips the sensor as a result!

So it's all good

 

That's a pretty good theory foz but the sensor is in the rad and not the top of the engine

It will stop when the temp of the rad drops and the sensor is satisfied

When the engine is switch off the water and oil pump also stops, this causes the heat to pool up in the top of the engine this in turn will trigger the high temperature switch and cut in the fan. The fan will continue to run until the water or oil temperature drops sufficiently enough for the switch to switch off the fan. Comes under engine management.