Interesting issue. Still trying to dope out what it is.
Bike starts normally. Everything fine until I step on the rear brake pedal and the dreaded red triangle pops up (solid - no flash). It stays lit till shut down and restart and the same thing all over again. As an experiment, I did 20 mins w/o touching the rear brake pedal and everything was jake. As soon as I step on the pedal, the triangle appears.
Seen it before? Any ideas? Come on "brain trust", help me out here...
Yes, I have seen this before - I even provoked the system into that mode to better understand the IABS system behavior for various faults.
The solid (no flash) Red-Triangle warning can appear in combination with a flashing or not flashing (slow or fast) ABS-Warning (the other Red warning). In your case, based on behavior and circumstances that you have described, I would say 90% sure it is a non-functioning rear brake switch.
For IABS (ABS with electrical servos) a rear brake-switch defects can include the following cases:
(1) If either front or rear brake switch is unplugged, it will cause a fault during self-test (withing 6 sec after ignition ON)
(2) Any cut wires in the brake switches circuit will have same effect as above
(3) On the other hand, if switch is connected but does not "click" when brake lever is pressed, you will get another type of IABS fault. Internally, the IABS modulator is able to measure fluid pressure coming from lever (or pedal) - when you reach a certain pressure (light to moderate), if the brake switch has not been activated at that point, it is considered an anomaly. This is why normal behavior is the switch should activate fairly early in lever travel.
CONCLUSION: I am assuming that your switch is plugged, no wire is cut, but the switch never "click" when pedal is pressed. You can confirm visually but switch is well hidden and even with engine OFF, the mechanical "click" is not very loud. Another way is to trace the switch connector and check continuity. On IABS system, these have reversed logic (continuity when pedal is at rest AND no-continuity when pressed).
IMPORTANT: make sure to check procedure to check pedal and switch adjustment as per shop-manual (or Clymer). This is critical for IABS system - otherwise you may have constant servos motor activation even when pedal is not touched.
Let me know what you find...