BIKE SURGES UNEXPECTEDLY AT LOW SPEED MOSTLY WHEN MAKING LEFT TURNS AND ONCE FROM A DEAD STOP. BIKE SURGE FORWARD CAUSING A CRASH AT INTERSECTION. I WAS SITTIN AT A RED LIGHT BETWEEN TWO CARS WHEN BIKE UNEXPECTEDLY SHOT FORWARD RAPIDLY CAUSE BIKE TO HIT CAR IN FRONT. DAMAGING BOTH VEHICLES.