I performed the shunt mod on the controller yesterday. The acceleration improvement was easily noticed even without a working speedometer onboard.
Today I had to ride home in the wet again. Something most XB-600 are not willing to do, but I've done fairly frequently because I put a good deal of effort into water-proofing everything.
I forgot to put my camera in my bag before leaving so I didn't take any in-progress shots unfortunately.
I took the front wheel off the front fork and made a bracket out of sheet aluminum to hold the sensor. I then drilled and tapped a hole in the rim to screw the magnet into.
Since the bike computer turns itself on and off I don't really need free access to its buttons all the time. So I installed it into the gauge console where the voltmeter used to be.
I soldered leads onto the contacts of one of the panel illumination bulbs and wired in some red LEDs to illuminate the bike computer since it doesn't include a backlight. I also replaced the indicator bulbs with LEDs by simply adding a resistor to them, heat-shrinking the resistor, then wedging the LED into the original socket.
After measuring the wheel radius with me sitting on the bike and then inputing the circumference from that measurement, my top speed on level ground is displaying at 19.5mph. The stock speedometer was optimistically off by about 4mph.
What is coming next will depend on what shows up in the mail first.