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 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.