My apology for not being more precise. What I meant to say was stand on the right side of the vehicle. (Left and right are always used in reference to the rider sitting on the Spyder.) So, you're on the throttle side of the Spyder looking to the rear of the machine. If you look down at the master cylinder, in reference to a clock 12 o'clock is facing directly to the rear of the bike. The vent is pointing at 11 o'clock, or in the direction of a line from the center of the cap to the right rear taillight.
View attachment 171568. Now in the picture, the top of the picture faces to the left side of the Spyder. You can see the vent on the cap between the C in the word "CLEAN" and the G in the word "REMOVING." Sorry, I don't detail my master cylinder.
If the vents are pointing toward the throttle, as you say, they are pointed in the wrong direction and you may have lost brake fluid out of the vent since the master cylinder slopes downward from rear to front. The loss would be very gradual until the level triggered the low fluid sensor. Hope this clarifies things a bit more for you.
