Morning - my 97 F3 has recently started to purge water back through the water tank when stopping on long runs. When running around town all is good with no water purge / spill. I have checked and cross checked head gasket and compression, there are no issues there. Compression is good and there is no trace of gas emitting through the water jackets into the cooling system. When the bike is idling you can see water flow / movement in the top of the radiator which tells me the water pump is working.....
My thoughts are now leading to that maybe when the bike is at full operating temp after a good blast that the impeller maybe coming loose on the water drive shaft and thus not circulating the water through the system correctly.
Oh, as we will live in SA the thermostat is removed....average daily temp is around 26 to 34 degrees.
The radiator was re conned recently.
So has anyone had similar experience in this regards?
Any other possible suggestions or insights will be appreciated.
Scott.

 

Have you pressure checked the radiator cap itself?

 

Hi, I had checked that year back - do you perhaps know of the pressure setting required for the Rad Cap?

 

It should say it on the cap. Usually they are 13 or 16 lb caps.