My '13 Monster ABS has an even worse issue... besides the 'upside down' bleed screw. The ABS valve body is mounted high up on the frame, under the tank. So, the line travels from the pedal, UP to the distribution block, then DOWN... past the exhaust... to the caliper. Trying to pedal bleed this system is impossible because any air in the system goes UP to the distribution block... and stays there. You can get a better pedal temporarily... but it's gone in less than 6 months.
Similar design on the MTS. Some folks have put a speed-bleeder on the rear brake line/ABS banjo, or at least cracked it to bleed at that high point. One of the recommended post-bleed steps is to engage the ABS about 10 times, then bleed again. I did find more air bubbles after the ABS cycling.
For those affected, these gyrations tend to fix the problem for several months or so before the soft pedal returns. YMMV.
