The fan will continue to spin at a slightly slower rate. Heat will be lower.
Just back from my latest Cannonball ride,,, And the F2's did a great job. As far as modulation goes,,, we used it all the way,, on both high and low beams. And as far as driver reaction is concerned,,, I had some different and interesting reactions, compared to H4's. But that is a topic for a modulation thread. The point here is,, the F2's performed well,, despite the fan speed being impaired by more than %50,, in imho. I don't have anyway of measuring the result,, other than that they did not fail. Only further testing will tell. Obviously,,, being able to power the fans at their full intended speed would be preferable,,, but maybe it does not matter,,, Cat'
OH, one neat thing. I used to wish I had some kind of a dash indicator that shows when the H4's were modulating. With the F2's,,, you don't need that,,, because you can see the pulsing reflection in the road signs,,, even in the brightest sunshine !!