No, not all motocross bikes have lowered suspensions. Motocross bikes typically have high-performance suspension systems that are designed to handle the demands of off-road racing. These suspensions are often adjustable to accommodate different rider preferences and track conditions.
While some motocross riders may choose to lower their suspensions for specific reasons, such as improving stability or maneuverability, it is not a standard feature on all motocross bikes. The suspension setup can vary depending on the make, model, and intended use of the bike. Riders may also make adjustments to the suspension settings based on their skill level, riding style, and the terrain they are riding on.