You should first determine the basic construction of a homemade ATV and the tasks for which it is intended. For participation in competitions often use design with rear chain drive, pendulum suspension (as on a motorcycle) and a rear axle without differential. Front suspension in most cases is independent, on the wishbone. In a sports car it is very important to reduce the weight that positively affects the handling, and increase specific power for good acceleration. Therefore, the two-stroke single cylinder engines are used.
ATV utilitarian purpose is usually quite large in size and weight. The most important characteristics of such a machine is reliability, high throughput and the ability to move useful loads. The most used four-stroke engines, with good torque. Rear axle equipped with a differential. The drive wheels via the propeller shaft. Front suspension is double wishbone. The drive can be both full and rear. All-wheel drive helps to improve the maneuverability of the cars, however, significantly complicates the design.
By identifying the purpose and basic design features of the ATV, you can go to the selection and purchase of components and assemblies. For utilitarian vehicles are often used engines from motorcycle "Ural" with the rear axle of a classic Lada. There are design which are applied to the motors from cars. Wheels also the car, along with wheel hubs and wheel bearings, brake discs. For sport ATV better to use as a "donor" sports bike imported.
The frame of the ATV should have sufficient strength and stiffness. Usually the frame is made of pipes by welding. The use of bolted joints is not recommended. The engine is fixed to the frame through the rubber seals that are required to reduce vibrations. Prior to Assembly, it is desirable to work out the frame design on the paper. If the experience of Assembly and welding works are not enough, better to turn to professionals for auto body repair.
When the frame is ready, take the time to putty and paint it. Do a control Assembly. Ensure that components and assemblies are correctly positioned in the frame and are joined together. If there are inconsistencies, correct them. After the control Assembly, you can start painting the frame. Try to do color accurately. Poor quality paint leads to corrosion, which adversely affects consumer qualities and appearance of the ATV.