Kick start refers to a method of starting an internal combustion engine (usually that of a motorcycle) by pushing a ratcheting lever with one's foot. Kick start mechanisms were almost universally a part of motorcycle engines before the mid-1970s, and were phased out of production over the next twenty years or so as electric starters became standard equipment. There are still some motorcycles produced that have both a kick and electric starters.
Many mopeds and scooters also carry both a kick start and an electric start, the former being useful in case the latter fails, as scooter and moped batteries tend to be smaller and, as a result, run down much faster than other forms of automotive batteries. Also, it is usually not possible to push start a moped or scooter with automatic transmission.
Larger motorcycles featured a manual compression release mechanism that made starting easier while modern units did this automatically through a cable attached to the kick start lever.
Today, dedicated off-road motorcycles and many ATVs use kick start systems due to the increased weight of electric starters. The majority of the inexpensive two-wheelers and sometimes three-wheelers in developing countries also use kick start levers.