Fan

[Ratters]

I’m trying to work out if my water pump or thermostat are ok.
Took it out for a blast and left it running a while but the fan doesn’t kick in.
How often does the fan come on if left idle usually?
Cheers.

[Grahamm]

The fan should kick in when the thermostat reaches 100 degrees.

If you check the service manual, there should be a test procedure to check it's working ok.

[darrsi]

Takes a lot of heat for the fan to kick in.
In this weather you'd have to leave the engine running for ages for it to even consider coming on, they handle the heat very well.

[Ratters]

Ok thanks gents also Imput a new rad on and drained and flushed the whole system.
Filled it from the top end but the overflow resevoir remained empty, do i just top up from that end or do I have a blockage?

[darrsi]

Ok thanks gents also Imput a new rad on and drained and flushed the whole system.
Filled it from the top end but the overflow resevoir remained empty, do i just top up from that end or do I have a blockage?

Did you use Radflush to clean the system?
It's all the waterways that get bunged up over time, and Radflush works similar to descaling a kettle.


You can top up the overflow bottle, but only do it when everything has cooled down.


Once the system is all good the coolant will rarely need to be topped up again unless the bike is in extreme heat.


When the system eventually gets clogged up over time, the waterways narrow and you'll get more fluid in the expansion tank which will eventually boil over then get released onto the floor via the overflow pipe.
Then when the bike cools down it sucks what is in the expansion tank back into the main system.


So it's a good pointer that your coolant system is healthy if the coolant sits back in the same place in the expansion tank when the bike cools down.
If it is low, or empty, you need to do the Radflush treatment.

[darrsi]

Overflow bottle / expansion tank - same thing

[Ratters]

Thanks Darrsi
I’ll do the  rad flush thing the coolant that came out was a bit minging.

[unfazed]

I’m trying to work out if my water pump or thermostat are ok.
Took it out for a blast and left it running a while but the fan doesn’t kick in.
How often does the fan come on if left idle usually?
Cheers.

In 19.5 years and 97000 miles my fan has come on 3 times. Each time was in summer when tempreratures were close to 30C weather, Wouldnt worry much about it as it has an exceptionally efficient cooling system

[darrsi]

I’m trying to work out if my water pump or thermostat are ok.
Took it out for a blast and left it running a while but the fan doesn’t kick in.
How often does the fan come on if left idle usually?
Cheers.

In 19.5 years and 97000 miles my fan has come on 3 times. Each time was in summer when tempreratures were close to 30C weather, Wouldnt worry much about it as it has an exceptionally efficient cooling system

Just bear in mind you have some of the most ghastly weather ever where you live, I speak to my Dublin branch quite often and I don't recall him saying what a lovely day it is over there 

[darrsi]

Thanks Darrsi
I’ll do the  rad flush thing the coolant that came out was a bit minging.

Empty what's in the system, PUT COOLANT BOLT BACK IN LOWER DOWN, empty the whole bottle of Radflush in, then fill up to the top with water. Then it's up to you, you can either go for a 5 or 10 mile ride in this cooler weather, or you can simply put the bike on the centre stand and let the bike tick over for 10 to 15 minutes.
Letting it tick over might even get the fan to eventually turn on.


Once you're done, flush everything out with a hose, then slowly fill the system up with the proper coolant mix trying to avoid glugging it in creating trapped air.
What i normally do is then let the bike tick over, even VERY GENTLY using a bit of throttle, with the thermostat cap off to let any air bubbles escape which will rise out to the top as the coolant cycles around the engine.
Then switch off, fill coolant right to the top, cap back on, and your system will be good for quite a while.


Just a note for anyone else reading this, this much cooler weather is ideal for doing the Radflush treatment because you don't want the bike overheating when there's mainly just water in the system, because the engine will boil plain water just like a kettle if it's already hot outside.