I've found that you can't count on beating a Banshee all the time, at least in the sand. Stock for stock, the Banshee is no match for a Predator. But once you put pipes on it, watch out.
My friend Chuck, who has a Raptor and a Banshee (with pipes) says his piped Raptor will beat his Banshee on hardpack, but on the dunes, there's no contest.
I can beat probably half of the Banshees I race on the dunes... they're machines that are either tired, or the riders just don't know how to ride them well. Two-strokes seem to require a lot of skill to go fast.
But then the other half, no way. I'll get beat by anywhere from two to eight lengths. These are machines with pipes, jets, and maybe reeds too. Heck, Chuck just got his new Toomey T-6 pipes, which are worth an additional 10 hp over the older T-5 pipes, so he'll be beating me even worse now.
Rob