I installed a new main jet, fuel filter, and clamp on air filter, in addition to a battery. The bike will start and run without a battery but the ignition cuts off at high rpm. On the subsequent test run, the top speed was a GPS indicated 34.4 mph (55.4 kph) before I ran out of road. I installed a new #70 main jet, but will experiment with a larger #75 main jet in the future. The original jet size was a #72.5 but a new one was unavailable.