Motocross is a discipline capable of offering exceptional sensations, and the motorcycle used is specially designed to withstand the extreme conditions associated with this sport. The motorcycle draws a large part of its capacities from the engine. If, for any reason, you decide to change the engine of your motorcycle, you should be aware of certain characteristics. To maintain or increase the performance of your motorcycle, you must choose the right motocross engine to have installed.
The displacement corresponds to the size of the combustion chamber, and the bigger it is, the more powerful the motorcycle is. On a motocross motorcycle, it is common (but not required) for the engine to be single-cylinder. This design allows the engine to deliver power faster.
The choice of engine power depends largely on the weight and size of the motorcycle. For a larger and heavier frame, a powerful engine is required. For example, smaller motorcycles often have an engine smaller than 125 cm³, and larger motorcycles often have an engine larger than 250 cm³. If your motorcycle is a 250cc, and you replace the engine with a smaller displacement, performance will be greatly reduced. It is best to take an engine of the same size or a larger engine.
2-stroke or 4-stroke
The combustion engine can be divided into two categories: 2-stroke and 4-stroke. Each category has its own specificities as well as its shortcomings.
With a 2-stroke engine, power is quickly available and the engine easily takes its turns. An engine cycle corresponds to one revolution of the crankshaft on the 2-stroke engine, which is why it is very nervous. The disadvantage with this engine is that it easily reaches its limits and wears out very quickly. The engine’s lubrication system is not very optimal and frequent repairs are required.
The 4-stroke engine works differently. It consists of a large number of parts and repairs are more complicated in case of breakage. Nevertheless, the 4-stroke engine wears less quickly and is more robust. Repairs are seldom to be expected, because the engine parts are soaked in oil. Performance is better, and the engine delivers torque from the first few revs.
The 2-stroke engine is more powerful than the 4-stroke engine, because with the same displacement, 2-stroke engines give twice as much power.
The cooling system
Cooling allows the engine to maintain its operating temperature. This is the temperature at which the engine performs best and wears out less quickly under these conditions.
On motocross motorcycles, the most commonly used cooling systems are air cooling and water cooling.
Water cooling is very efficient, but is quite cumbersome. This system requires the use of a water pump, a radiator and water pipes. Air cooling requires none of these components, but cools the engine less efficiently.