The average top speed for a 400cc dirt bike is 87 miles per hour, although there is a significant speed gap between different models. The largest speed gap is between Suzuki DR-Z and Honda CRF, at 17 miles per hour. At 400cc, there is a dramatic change of speed.

In the chart of surveyed dirt bikes, the average top speed for 400cc-450cc dirt bikes is 96.67 miles per hour. The largest gap in speed exists between the Honda CRF and the Suzuki DR-Z, at 17 miles an hour. The top reported speed of a Honda CRF is 87 miles an hour, while the top reported speed of the Suzuki DR-Z is 114 miles per hour.

The top speed of dirt bikes with a 400cc engine varies widely between different models, but on average, these bikes can reach 87 miles per hour. When comparing top speeds, the Suzuki DR-Z and Honda CRF have the largest gap, with 17 mph. Increasing the engine size to 400cc makes a noticeable difference in velocity.

The fastest dirt bike on this list is the Suzuki DR-Z, with a 400cc four stroke engine and a top recorded speed of 114 miles per hour.