I figured out why my bike now and then throws a "low voltage at the ABS sensor" when starting my bike. I believe stage 3 cams are compression release. And so when I shut off the bike and its very close to TDC on a compression stroke and upon restarting it the engine will finish the compression stroke without the release. The engine stops just for a very brief moment and then cranks and starts. At this point of hesitation with the starter engaged it draws heavily on the battery dropping the voltage below the 12.6 volts thus telling the ECU to stop sending voltage to the ABS system and throwing the code.