I had a similar problem on my NTV, in fairness all I did was remove the switch and wire it up so the fan was just always on, soon stopped the problem, you could place a switch inline so it’s not on all the time, if I remember correctly, all yuo have to do is pull the wire off the switch and ground it (touch it to frame) and the fan should come on, if it does then the fan is ok and the switch / sensor is knackered, hope this helps.
In the end after a few months, I did plug the switch back in and it was magically working but during that time, I had removed the fairing from the bike…
well they have changed the switch and it has not fixed the issue. I have asked them what else it could be as the pump has an impeller so shouldnt be that.
Guys said it could be a blocked radiator which is £250 + VAT EACH!
The bike is 12 years old and its a great bike but I am loathed to lay that money down. I reckon this must be something I can do myself. The crap thing about living in the bike smoke is I no longer have a garage so could crack on at my own pace.
Errr, I would test a blocked rad by removing all pipes from it, putting the hose in at the top point of it and see if the water comes out the bottom, leave it running for a bit as it may flush out some ****, if it doesn’t come out then it’s blocked, it will probably come out brown water at first but leave it going until it’s clear and then that should get all the gunk out of it. I’m not a mechanic by any stretches of the imagination but this is what I would try and it would confirm whether it’s blocked or not, you should after a few seconds, see water coming out at the same rate as it’s going in and at least it would clean it out as well.
Also is your temperature gauge rising? Does the bike cut out at any point or does it just keep going and just lets coolant boil out? Also if you check your oil, is there any like what mayo looking substance near the cap at all?
check that the thermostat is actually opening. the fan switch is just that, a switch. it will usuall work, or it wont. if its mounted in the radiator (which i believe it is) it will only operate if the water in the radiator gets hot enough to trigger it. your temperature sender, reads coolant temperature from the motor, not the radiator. if your thermostat isnt opening properly, then hot water from the engine, dosnt make it to the radiator, dosnt set off the fan early enough, and dosnt let cooler water from the radiators reach the engine
So its not the thermo switch, its not the thermo itself (both replaced) they are now telling me they think its the impeller?! Now correct me if im wrong, but the impeller is a single cast piece of metal so how would it go faulty?
Some cost cutting c##t of an accountant decided it would be a good idea to change impellers from metal to being made of plastic (affects cars too)
So the impeller fins can somehow degrade and wear out over time. Another good reason to flush out the cooling system with a hose when doing coolant changes, try and get any particles in the system flushed out.