When the Zero X wheeled onto the dirt track at Lake Elsinore, the Colgate-white motocross bike looked positively virginal next to the belching, candy-colored models that leaped from mound to mound around it.

Not surprisingly, the Zero X drew a lot of attention.

Two-stroke? Four-stroke? That wasn't the question riders were asking after watching the electric dirt bike roll around the track a few times...