This seems to be an age old problem for me so was hoping you fellas might be able to point me in the right direction.

The bike just gets too hot and the fan doesn't seem to kick in, where there after it boils and pukes its coolant out into the over flow bottle...not good!

I have checked that the fan works by earthing it and this is good, replaced the temperature sensor in the bottom rad, checked the thermostat is working - looks fine, no leaks on the rad cap and the temperature sender is in good working order....

I have also flushed all the rads and given the bottom one a good clean....
My only other port of call is the water pump!

What do you folks think??
Any help appreciated

Im not totally sure about how it effects everything but check your thermostat. What I do know about it is that if it sticks shut then things dont circulate properly...

Yep, checked the thermostat - it seems to be working absolutely fine......

So..you need to know why the fan doesn't kick in then?

Have you checked the temp sender on the rad is working?

I have checked the temperature sender (by the thermostat) with regards to earthing the wire to see if the temperature gauge is working...how else should I check the sender??
I thought the temperature sensor in the bottom rad actuated the fan???!!
Excuse the novice reply!

So, as per the previous thread....
How do I check the temperature sender??

I have earthed the wire to see if the temp gauge is working and this is fine!
Where does the fan read its temperature from to allow it to come on and will the sender affect this??
A little confused now......

the fan gets the kick from the lower rad I reckon..on the left hand side..

Checking the water pump is a doddle.. just remove the cover (drain the coolant first) It is worth checking its condition occasionally... do not pull the pump out of the engine though else the oil will follow... with the cover off and the blades exposed crank the engine a few times to check it turns ok.

If you pull the wire off the temp sensor and earth it the fan should come on! This is the fan sender..

now if the fan comes on when you earth the wire but not when the bikes boiling over this sensor is probably knackered.

If you earth the wire and the temp gauge goes to the top you have the wrong sender, keep looking.