We just got our mitts on the 2007 Honda CRF250R and took it for its first shake-down ride at Perris Raceway. After a day on the well-prepped, supercross-obstacle-strewn course, with a 106 degree heat thrown in, we have our initial impression of the new bike.The 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.Honda put a lot of changes into the new carb. The two most significant are the new accelerator pump linkage and a new accelerator pump fill design. The carburetion is cleaner and crisper and responds to hitting the throttle upon landing better than last year.The front forks have gone though a re-valve which, naturally, improves the rear shock. It’s true – the rear feels more confident in response to the front working better. The rear is firmer, but not stiffer. It feels more planted and less jarring. Both ends still have good bottoming resistance.Some of the other changes include the front tire, the Dunlop 742FA, which was great on the prepped track – we’ll see how it fares on less-than-ideal dirt. The bike also gets a new header, a beefed-up clutch, a one-piece throttle cable and a lighter chain guide.Like the 450, the front brake lever is a significant upgrade. Where last year’s lever had a falling-rate leverage ratio, this year’s has a rising-rate. In the earlier design, the brake had the most leverage at the very beginning of its pull, and lessened as more brake was applied. This year the ratio is reversed. Now the brakes get stronger as you need them stronger. It’s noticeable at the track, with better control entering the corners.The bike felt amazing at Perris on its intro day. Now we’ll test it at different tracks in various conditions for the full test in the magazine. So far we’re impressed with the refinements to a bike we’ve clearly been fans of. Sometimes small refinements can go a long way. And the real questions are, is it enough to stay at the top of the class, and should you step up and buy one?