Motorcycle Trials, also termed Observed Trials or Observed Motorcycle Trials, is a non-speed event on specialized motorcycles.
Trial motorcycles are distinctive in that they are extremely lightweight, lack seating (they’re designed to be ridden standing up) and have suspension travel that is short, relative to a motocross or enduro motorcycle.
The event is split into sections where a competitor rides through a natural obstacle course while attempting to avoid touching the ground with the feet. In many local observed trials events, the sections are divided into separate courses to accommodate the different skill level of riders, who compete in skill-rated classes.
In every section, the competitor is scored by an observer who counts how many times the competitor touches the ground with the foot (or any other part of the body). Each time a competitor touches the ground with a foot, the penalty is one point.
The possible scores in each section consist of 0, 1, 2, 3, or 5. If a competitor makes his or her way through the section without touching the ground with a foot, a score of 0 is earned.
If he or she touches the ground only once, the score of 1 is earned. If he or she touches down twice, the score of 2 is earned. If he or she touches the ground three times or more, the score of 3 is earned, as long as the section is completed without stalling the motor, dismounting, going out of bounds or going backward. If the competitor fails to complete the section a score of 5 is earned.
The winner is the competitor with the least points at the end of the event. Some events are also timed with penalty points assessed to late riders.
Major current manufacturers of trials bikes are Gas Gas, Beta, Sherco, Montesa Honda, and Scorpa. In the past there have been many manufacturers, from countries such as Spain, Japan, Britain and Italy.
(from Wikipedia)