The manual for my 2010 ZX6R says the fan should come on at 100c.
Having just fitted a new rad, running the engine with the bike stationary, and the fairing off, the temp guage is showing 103c, and the fan is still not kickin in.

I've seen mention on other websites about the fan starting at higher temps, but ...
1. What is usual real-world temp for the fan to start?
2. What is the tollerance on 100c?
3. What is the temp you should definitley stop the engine at?

Is your thermostat definitively working?

That would be the first thing to check at a guess.

The temp sensor that feeds to the dash seems to be working.
Whether the relay for the fan has failed, or the fan itself, or something else, as yet I don't know.

102 is the normal for a fan to cut in...check you haven't disturbed wiring...the other thing is of you have an airlock the water temperature sensor may well not be getting a proper reading.

If I remember correctly my last couple if zx6's fans came on about 105

Thanks all. Finally managed to get the fan to run at an indicated 105c.
A little warm, if I understad correctly, but at least it's working as we get to the warmer weather!

in traffic my fan came on at 105 and then went off about 98-99.