Just as the title really, at what temp should they kick in? My ride home is fairly free flowing so my engine is never roasting when I get off it. But I have seen the temp needle over half way when I'm in heavy traffic. I can't tell then though other fans are running.
Around 102 to 105c I believe depending on if you are looking at the gauge or taking it from the stated specs of the bike. Running in the middle of the gauge is quite normal and my fan rarely comes on when I am riding as the engine cools rapidly as soon as I start to move through traffic. Easiest way to test it is to run the bike with the panels off and see what temperature shows on the gauge when the fan starts up and and when it stops. The thermostat can govern when the fans come on in as much if it is stuck partially open, as mine once was, the bike will take much longer to warm up and mine actually ran quite cold even when riding it. Replacing the thermostat gave me proper warm up and more efficient running as the ECU temperature gauge was then able to weaken the mixture off to the correct level at the proper running temperature. If the bike runs too cold you can get problems with starting and running as the mixture is governed by the temp sender to the ECU. There was an article on this on Ducati MS covering this.
