First things first, the bike is practically all-new emphasizing and incorporating the changes made to the 2006 YZ line and its new engine and frame, while tuning it to meet the demands of the off-road rider. Changes from the motocrosser are subtle but make a huge difference in how the bike performs off the track. And Yamaha took even further steps in tuning the machine, claiming to have designed it to work better for the tighter and technical trails, not so much for the faster and open terrain out west where the settings used to perform best.Our ride entailed everything from fast dirt roads to snotty and slippery clay jungle trails. Dodging monkeys and downed journalists alike, we can say the bike is an improvement from the previous steel-framed version. Much like the WR250F, it has a lighter initial feel and is a lot more maneuverable. You still feel that you are on a 450, but it is a lot more along the likes of the CRF and even more so the KTM in light feel. It is thin, feeling just the MX bike! The suspension was supposed to be a lot more plush and lighter in valving to blow through the stroke more in the rocks and roots. The 250F is set up like this for sure but the 450 is a little bit stiffer. It may be set up for slightly faster and heavier riders, and a 450 is always a bit more difficult to get set up for the gnarly conditions. Our bike may just need a little more time to break in as well. We’ll know in a few more days of riding down here.The engine is good ‘ol WR – strong with its characteristic smooth and deliberate power. It has a very snappy and responsive bottom end that will light up the tire pretty easily, especially on clay, but will also torque down really good too. Sometimes it feels like it could use a little more flywheel and it has a slight stalling problem, but the fuel down here is making the low-end jetting a bit finicky. Our bikes are running in fully uncorked, competition settings, unlike the corked up way that they are sold at the Yamaha dealer, but they are still extremely quiet. Only the smallest stuffer is removed from the muffler.It’s tough to file a ride report while sitting pool-side, with killer waves to my back and awesome trails in front of me, but I lost a bet with my fellow journalists (how fast I could get this ride report done) and you dirtrider.com readers are the recipients of the reward. If you are thinking about a WR, we highly recommend one, especially if you liked any of the older versions. This one is way improved. And transplants from other brands will surely find some Yamaha traits to appreciate.Look for a full test in an upcoming issue of Dirt Rider.