Most will stay about in the center of the gauge for normal temp, about centered on the temp symbol, the fan on mine kicks on when the needle is on the right half of the symbol.
At 65° today, I had to let it idle 10-15 min. before the fan came on. 35mph in the summer will keep mine at normal temp without the fan, had to run home without it once. The spade terminals in the plug at the junction box were loose fitting and stopped the fan.
In hotter weather, my fan will kick on at least once after shutdown.
The fan switch isn't adjustable. If you ground the wire for the fan switch, the fan should kick on, if you want to test the fan.
Always a chance the thermostat is stuck open, making it run too cool. With the radiator cap off, start it cold and see if it's circulating right away. If it is, the t-stat is stuck open or someone took it out.
And finally, on cooler days, mine may not get to full normal temp, depending on how I'm riding, how far, etc.