Motocross riding is one of the most high intensity extreme sports in the world. It involves all-terrain outdoor riding, basically which means that all kinds of courses, whether rocky, or muddy is used for most motocross events. The races are obviously held in enclosed circuits but always in public places around the world. It involves speed and a high amount of bike control during race performance.
Therefore it is absolutely essential that the bikes be in top shape and are built using the best motocross parts that are available in the aftermarket industry. A faulty dirt bike could spell disaster for a racer going high speeds on the outdoor course.
In the aftermarket industry, parts of motocross bikes fall under highly specialized motorcycle categories. That is to say, bikes from different manufacturers will have different manufactured parts and in this highly specialized sport, there can be no compromise. So, a Yamaha bike will have differently structured parts available as compared to a Kawasaki bike for example.
One vital part for motocross, or for that matter, any kind of dirt bike is brakes pads. Well maintained and top of the order brakes are essential and can make or "brake" any riders finish. Jokes apart, to maintain brakes pads, parts like brake hardware, brake lines and brake rotors are things that a biker needs to look at before the race. Motors are another thing that needs close attention. Carburetors, clutch plates and engine valves on the 4-stroke are integral components of an engine that will brake without maintaining them.
Motocross Exhaust systems are essential for any bike and more so for high speed, all off road riding that entails to the motor. With header pipes and silencers being some of the main components, an exhaust system radically improves the look and sound of the bike to stay under 96 disables without loosing power to the motor. The silencer will need serviced on regular bases before the insulation burn out and cause the motor to over heat and raises the disables over the course limit.
Other major parts are suspension parts, tires, wheels, guards or braces, fuel systems, ignition etc. These are the departments that any rider needs to look at while maintaining a bike especially for motocross racing.