Original sentence: In 2006, Honda replaced the XR400 with the CRF450X.This bike was discontinued in 2004, replaced by the more modern CRF250X
Edited sentence: In 2004, Honda discontinued the XR400, and the modern CRF450r motocross design from 2002 took over.This bike was discontinued in 2004, replaced by the modern more high-output/maintenance CRF250X