Never seen a bike with a properly functioning reg/rectifier that consumes voltage from a battery.
Yeah, so adding a diode to the banshee which does not have one will result in a .7v drop. Not to mention, if your way is so easy to do, then how come none of the manufacturers, or aftermarkets do it, or talk about it. The reg/rec setup with a battery is industry standard stuff through RS, Trail tech, and most of the aftermarket starter companies for snowmobiles like Goki.
Auto alternators are 3 phase, with 3 zener diodes in the housing to rectify out dc voltage.