After a day of riding on the all-new Kawasaki KX450F here's the first scoop. It really is an all-new bike. And it is much different. Kawasaki hosted the press introduction of the bike with every U.S. journalist (if you can call us that!) at Muddy Creek Raceway near Blountville, Tennessee, and our bike has been running all-day long.The first thing you'll notice about this bike is the easy starting. It is as simple as it has ever been, if not easier. It takes no more effort or even thought than the previous carbureted bike, which seems better than any of the other FI MX bikes we have tested. And as you should expect, the throttle response, fuel delivery and everything to do with the FI system is flawless. You have nothing to fear here. In fact, EFI has allowed the all-new motor to be a lot more friendly and still pack all that great KX450F power as well. Off the bottom there is still some pretty good snap, but it is tamed compared to the hit of the '08. Then it pulls in a very linear fashion through the spread with a bit more gusto than has seemed typical of FI bikes, meaning it remains plenty exciting. It revs out to a decent top end with plenty of power, that is for sure, but it seemed like it was easier to use at the same time. And another character of the motor is that it felt more like a smaller-bore bike, as opposed to a big-bore. You feel less of the chug and each stroke blends in with the next. As a result it is a lot easier to maneuver the bike at higher revs, and this with a slightly higher compression piston inside there too. And the throttle control up in the revs is so responsive it makes spinning the motor even easier. Conversely, this is one motor that will also work well a gear high and pull with big throttle openings, pulling almost as well as if you'd downshifted. This seems to be one versatile engine, and we haven't had the opportunity to tune it with the optional engine management software. That should really make some big differences if you know what you are doing.The next thing we expected was a radically lighter feeling bike. But it wasn't. Compared to the 2008, it is definitely a lighter and more agile ride, but not as much as we'd have expected. But what the KX keeps is a really stable package and some very plush suspension that lets you ignore the little bumps on the track and concentrate on the big ones. What it feels like is that the chassis got more compact and lighter but the wheels and unsprung stuff didn't lose much weight, therefore the feeling isn't as drastic as it could be. Kawasaki claims the bike is exactly the same weight with the additional gains from the FI equaled by dropping pounds in other critical areas. At the same time they also beefed up some durability concerns inside the top end and transmission. But what has happened is the chassis became more sensitive to settings and we definitely played around with the suspension to get the handling feel we wanted, not because the suspension was doing anything funny, but for better turning feel.My initial impression was that I wanted to put a little more weight on the front wheel, and I spent a good portion of the day taking small steps getting to what I felt was a pretty good setting. In fact I felt it was a whole different handling bike after going back to stock to verify it. I set up our KX with a little less sag than recommended (109 vs. 112mm) a 1/4 -turn more high compression on the shock, a couple of clicks of both compression and rebound on both the fork and the shock, which slowed everything down just a little bit and really got the front end to stick. The suspension still stayed plush and controlled and does a pretty good job of resisting bottoming with my 190 lb., expert-speed frame. I'm pretty sure slower riders will be just fine with the stock settings, but riders above 215 lb will be looking at springs for sure.The track was harder packed dirt and had plenty of variety, with off-camber turns and kicky jumps. It definitely taxed both the turning and the suspension but what shone through was the motor, which was so good you hardily noticed it. And in just spending a good day riding and looking at the bike, it is obvious Kawasaki did a really good job refining a lot of little things on the machine too. The radiators are braced like crazy, and the shrouds are a more simple design. The bike isn't the quietest, especially to the rider on the bike or when it is wide-open, but it sounds toned down compared to 2008. The clutch action was pretty smooth and was magical on engagement off the start line. It was really easy to get a smooth launch and get out of the hole hard. We did have some issues knocking the bike into neutral from second gear but we're pretty sure it was our foot knocking the shift lever or the lack of a solid shift in the first place. Perhaps we just need more time with the wider footpegs. And the thinner and flatter layout made it easier for tall guys to get along with the KX, they didn't feel as cramped as they did on the previous bikes.So after a day on the bike we can't wait to get the KX450 back to California and get rolling on comparing all the 450s to see where the cards fall. There is no doubt that this is a hugely improved bike, and if you like the stuff Kawasaki has been offering, this KX is staying that path. They didn't do anything radical, except change the whole bike. And everything they changed hit the spot.Want to know more? Help us test this bike for you by telling us what else you want to know about it. Click hereto go directly to our message board thread set up for these questions.