The Zero S electric motorcycle is impressive, but be careful with the throttle--it accelerates superfast from a standing start--and keep in mind that it weighs only 225 pounds. Those are the initial observations of this first-time rider, who took the street model made by Santa Cruz, Calif.-based Zero Motorcycles out for a spin. It's an odd feeling to twist the throttle and feel the powerful acceleration (62.5 pound-feet of torque) and still hear no sound except a slight clanking from the chain, not yet lubricated on this pre-production vehicle. Making tight turns is a little tricky, as there's no clutch (and no gears). But once you get used to it, it's just like an ordinary street motorcycle.