The 2007 CRF250R7 engine gets a new cam, new valve springs to match the cam, and new head porting. The really interesting engine change is a small vent in the crankcase that allows the engine to work more efficiently, something the race team has been running for some time now. On the track, the bike has an improved low-end and a much stronger mid-range. The bike is now comfortable snicking a taller gear before a whoop section and pulling strongly through.