I had the same problem in Lake Placid this fall. It had gone down to 35*f. I hit the starter as usual. After 3 or 4 tries, I turned the throttle and it fired right up. I then RE read the manual and sure as can be it said if its cold turn the throttle.
Zero problems starting in the cold since.l
This where we were. 2 R1200R and an 800GS. I could see whiteface from the hotel.