A kick start is a method of starting an internal combustion engine. This method of starting the engine is most commonly executed on a motorcycle or off-road vehicle in lieu of an electric starting system. Most motorcycles in the past featured kick start systems as the exclusive method of starting the engine, but the application of electric starters to motorcycles has largely replaced the kick start method. Some motorcycles feature both an electric start and a kick starter; the kick starter is used if the electric starter fails for any reason. Motorcycles that are used exclusively off-road often forgo electric starters and feature kick starters only.
A kick start engine will feature a metal arm with a foot peg on the end. This arm will fit snugly up against the engine when not in use, and it will be pulled downward when needed. The rider will place his or her foot on the foot peg and push down forcefully on the arm, thereby starting the engine. It may take the rider several kicks to kick start the engine, especially if the engine is cold. Warm engines that have been used recently will start more easily in most cases, sometimes requiring only one kick.
Off-road motorcycles often forgo electric starters because they tend to be heavier than kick start mechanisms. An off-road motorcycle will use the kick start arm exclusively, which can make starting the motorcycle more difficult during racing or intense competition. It does save significant weight, making the overall performance of the bike better and more maneuverable. Many motorcycles, both on- and off-road, that feature kick starters often feature compression release capabilities as well. This feature makes starting the engine easier by essentially taking the compression from the combustion chambers out of the equation when starting. Otherwise, the starting mechanism will work against the force of the combustion when attempting to start the engine.
Kick starters can be difficult and even dangerous to operate for some people. Riders with knee or other leg problems may have difficulty engaging the kick start because of the resistance of the unit, and the kick starter arm can recoil quickly, potentially colliding with the rider's leg. If the kick starter arm is faulty, it may fall from its position next to the engine and interfere with rider movements during riding. It is important to make sure the kick starter is in proper working order, and the rider should wear boots and other protective gear when using it.