There's a lot to be excited about when new models come out. Updated suspension, increased power and new graphic schemes all rise to the top of everyone's most-wanted list. For 2006 Yamaha seems to be giving us all that and more with its new and improved YZ250F.The biggest changes you'll notice by just looking at the bike are the additions of a totally new aluminum frame, Pro Taper bars and the optional yellow and black graphic and plastic schemes available on the '06. It's Yamaha's 50th anniversary and they thought the throw-back colors were a good way to celebrate. We agree, that's why we rode the yellow model for the entire intro at Honey Lake MX Park outside Reno Nevada.The new YZ250F has a pile of changes under its skin as well. Things like Yamaha's new Speed-sensitive fork system and updated rear shock complete with titanium spring are major handling improvements. Engine-wise, the new YZ engineers paid attention to mostly mid-range power improvements and smaller functional changes. They built a totally new exhaust system, changed some ignition and carburetor settings and designed a unique-for-its-class external oil tank.We rode the bike hard for two days on the long, horsepower-robbing circuit of Honey Lake and were happily impressed with the way the bike worked. Although it's far too early to definitely say what works great and what doesn't work so hot, our first impressions of the bike are very positive. The new chassis seems to handle great, not beating us with rigidity or harshness. And the suspension is just as good as other YZ models we've tested this year (250 and 125 two strokes).We set the sag and turned laps, never feeling the need to make any other adjustments. We did experience a slight front end push in flat corners and we're currently trying to determine if it has more to do with bike setup or tire selection. Also, the bike seems to be more linear in its power delivery than years past; filling in holes or boosting bottom end power tends to do that. It pulls out of the bottom okay, just not as aggressive as we remember.Yamaha created the 250 four-stroke class with this revolutionary bike, and as evidenced by their 2006 YZ250F, they are still improving it. Look for a complete first test, and what's shaping up to be the hottest 250 four-stroke shootout ever, in an upcoming issue of Dirt Rider.