Fall is well underway, which means it's time for Zero Motorcycles to give its e-motorbike range a tune-up. The highlight for many will be the Zero SR: the red-hued, $16,995 flagship produces both 24 percent more power and 56 percent more torque than the Zero S, which takes it to 60MPH in a brisk 3.3 seconds. There's a little something for everyone, however. All 2014 bikes can use a $2,495 Z-Force Power Tank that extends the range up to 171 miles in city travel, and the company has refined the brakes, handling and suspension on the Zero S, Zero DS and Zero FX. Eco-friendly riders can request price quotes for the new bikes today, or at least whet their appetites through a promo video after the break.