Fan on and off temps changing

I have a problem with my radiator fan, it doesn't come on at the same temperature it used to and it seems like the fan isn't spinning as fast as it used to. The fan won't bring the temperature down , it continues to climb when I'm stopped at a light. Sometimes it does spin fast enough to cool it down but only after the temperature reaches 230F. The only thing I see on the wiring diagram is a fan switch, is this a failure mode for the fan switch? Any help or advice is appreciated.

 

Some possibilities:
Debris caught in the fan so it can't spin easily? (e.g. grass, a rock)
Bad earth reducing the current flow through the motor?
Dirty terminals on the thermoswitch reducing current flow?

I'm assuming you have an earlier model i.e. not 7th or 8th. There is a 12v live connection to the motor at all times, the circuit to ground is completed through the thermoswitch.

 

Do you know that the fan isn't spinning as fast as it used to, or, are you guessing that because the temp isn't dropping when the fan comes on?

 

The sound and I reached down and couldn't feel much air passing through the radiator, when it is working correctly the fan has a higher pitch louder sound and you can feel a lot of air going through the radiator. I'm thinking it's the fan switch.

 

Time to pull the fan and test it, along with the switch.

Edit: If you don't want to pull it apart, I would jump the plug directly to ground and the battery and see how the fan operates. If it runs normally, then you will have an idea on direction and level of effort.

 

Left field suggestion - Have you checked water levels in both radiators?

5th and 6th Gens can be a pain to refill completely after a coolant change. If there is a bunch of air trapped at the top of the radiator then the fan switch may not be below the water surface and it will not know how hot the bike is or when it needs to turn on.

SkiMad

 

No I haven't checked the water levels, what is the best way and how do you remove the trapped air?