ever figure it out? from the sounds if it, what's happening is a weak connection/broken wire (inside the insulation). you can have a connection that appears to be good and shows proper voltage while there is no amp draw. but when a load is placed on it, it can't "handle" the amp draw and will act like what your describing. hold this load long enough and it will eventually show itself by starting to smoke and melt at the bad location. this is not a recommended way of locating the issue. while I'm new to the busa myself, most starting systems had a switch with is a low current that feeds the coil side f a relay (a relay is just a powered switch). in a simple wiring setup, you would have a connection from the battery to the fuse block, to the relay high current feed then to the starter. when you hit the start switch it just energizes the coil in the relay to connect the battery power to the starter. it sounds like you issue is somewhere in this portion of the system. like your starter is demanding more current then a particular connection or wire is able I feed due to some kind of defect. I hope this is helpful if you haven't solved this issue yet
