This kit comes with everything that you'll need to convert your bicycle into a motorized bike, NO need to buy anything else. You'll still be able to pedal the bike and ride like normal or start the engine by releasing the clutch lever. There's no rope pulling needed. You can stop or start the engine as you ride. Twist grip hand throttle controls speeds from 25 to 30/mph depending on the gear ratio. (MPG 100-150) This installation kit comes with a 48 tooth 9 hole chrome racing sprocket with easy to install 9 bolt universal mounting hardware that clamps over the rear wheel hub and spokes. This creates a totally independent drive sprocket and chain that does not interfere with your current drive chain or peddling. With the built in clutch you maintain full function of the original bike. Pedal, shift, and ride your bike like normal. The engine kit only adds about 19lbs to your bike. When you want to engage the engine simply release the clutch hand lever and the engine springs to life. To power off simply press the included kill switch.