The low, steady thrum of a 250cc engine replaces the morning rooster as you slide onto a single-seat ATV and push away from a small village near Ubud. Mud sprays under the knobby tires; the track threads between rice paddies, crosses a narrow wooden bridge that bounces under your wheels, and dips toward a river that seems to dare you to pick up speed. For about an hour you’re steered by a local guide who times the route to showcase a hidden waterfall, a short dark cave tunnel, and wet-season puddles that turn routine into adrenaline.