Now that right there is a fascinating idea I think.....
A few free thoughts:
1) The air will flow better the way the fans work stock on the bike because heated air rises, and the vents where the hot air exits (all over the rider) are higher than the front of the radiator (the air intake).
2) The bike would have to be absolutely stopped because even a few MPH in speed will badly fight the airflow forward when the fans are reversed. This is not to say it will not work but my basic thought here is that the fans will not overcome even a 'walking' speed, so once the bike starts to move at all, the fans would have to go back to moving the air in the stock direction. At least that is my initial thought with absolutely no data at all....
3) In addition to the radiator, the fans also server to cool the exhaust pipes, which are much, much hotter than the hottest the radiator will ever become before the bike overheats. So that exhaust cooling would be lost; the result <may> be a very hot engine bay along with possibly overheating the exhaust header, the catalysts, the bike's frame and <perhaps> even some plastic and / or rubber component damage.
4) The heat will come out of the radiator and a lot of it will rise directly in front of the windshield. A better place than all over the rider but still not really moved very far away from the rider either.
So the above said, I think it is a terrific idea and well worth trying. Not all that hard to implement manually with a couple of switches but much more difficult to automate- still doable, just not nearly as easy as a 'quick 'n dirty' test. The idea has other benefits also such as the fans blowing the hot air away from the entire engine assembly rather than adding to the accumulating engine bay heat (maybe- see point 3 above).
What might be a viable mod. tacked onto your original idea would be bigger, more powerful fans. They could be regulated down for conventional use but put on 'high' when reversed to move a LOT more air backwards through the radiator.
A novel and interesting idea though I think.
Brian
<snip?
I had this idea a few years ago (and I think I mentioned it before)- what if the bike knew when it was sitting still or nearly so and REVERSED the fans so it blew the air (and associated heat) forward through the radiator and out the front of the bike instead of back toward the rider? I wonder if that would make any difference? And along the same thought, it might also be able to use a lower, constant reverse inbetween full blasts to continuously draw heat away from the rider but without the huge electric load and help make up for the reverse flow not being as efficient.