2009 Kawasaki KX250F 1

Are you ready for a tour of the nearly all-new Kawasaki KX250F? Well, settle in because there’s a lot to talk about. The amount of ‘new’ that’s built into this bike is pretty staggering. This is definitely no bold new graphics model year refresh for the 250F.

The Powerplant

The ’09 edition has an all-new engine, with new cases, new bottom end, and new top end. It also has a new tranny, and exhaust. They worked to add more bottom end power as well as more top end, but at the same time they also worked make it easier to ride.

Let’s start from the top and work our way down.

There's plenty of 'new' in the engine. Check out the new plate mounts up top as well. Click for a larger image.

The valves are now constructed from a new titanium material that’s stronger and more rigid than before. The head thickness on the intake side has also been beefed up, from .75mm to 1.0mm.

In talking with Seiichi Kai, the project lead on the KX250F, one of the things they were proudest of on the bike was the good response at low range, as well as big top-end power and good overrev.

We also asked him about why we haven’t seen EFI on the 250Fs yet, and he said that because the 450F have so much torque, it needs a smoother power transition compare to 250F. For the 450, the FI achieves this more easily than with a carburetor. Other reasons include the cost of manufacturing and the price balance.

The head features smoother intake ports with an improved surface treatment, designed for a boost in intake efficiency across the powerband, particularly at the high end. The routing of the cooling system has also changed, with the cluster of coolant tubes that were in close proximity to the exhaust now spread out. The cylinder outlet has also been moved from the side of the cylinder to the front.

Speaking of radiators, their width has increased 6.4mm, for a capacity boost of 6%. All four corners (front and rear) now also feature reinforced corners. The louvers in front of the radiators have also changed to boost airflow, both in the angle, and the number of louvers.

In the lower end, you get new cases that have a scavenger pump screen that’s similar to the KX450, which means it’s easier to access and maintain. They’ve also reduced the cam chain tensioner load considerably, which drops the mechanical loss by nearly 1/3. The clutch cable holder is now also cast into the cases, rather than using a bolt-on style. That means you get better rigidity and a better lever feel.

They’ve also boosted the crank balancer configuration to smooth the power delivery, as well as boost mid-to-high RPM performance. It’s also said to reduce the vibration, and be comparable to what they’re running on their factory race bikes.

In the transmission, additional space between the gear shafts allows for a boost in gear strength, and switched from a gear-driven shift system to a ratchet-style arrangement is designed to reduce play in the shifter while making for better feel.

The amount of engine oil has decreased from 1.5 liters to 1.0 in an effort to trim weight and power loss due to the oil churning around inside the engine. Take this as a reminder to keep an eye on your oil level, and to not slack on the time between recommended oil changes.

The engine also uses a new set of mounting plates from the frame to the cylinder to increase the rigidity. And that leads us to…

The Chassis

There’s no shortage of new in the frame, since it’s equipped with main spars that are shorter and narrower than in the past. Kawasaki claims that this maintains the same stability as before, but with easier cornering and a lighter feel.

Trimming weight was a big goal, and by the time you slim down the head tube, add a new lighter down tube (with trimmed weight, and adjustment to the stiffness), an all-new subframe that uses larger diameter tubing; and a new tapered swingarm, and you’re looking at weight savings in the range of 3.1 pounds.

Total up the weight savings in the chassis, and it's over three pounds.

The subframe itself uses a larger diameter tubing, and wider mounting points at the upper end for more strength. They also simplified the design and construction, using the same bracket for the exhaust and fender, rather than splitting the mounting duties between two brackets.

As for the swingarm, its pivot point has been raised 3mm in an effort to improve rear wheel traction, and it features a new tapered D-shaped design that’s taller in the front, and shorter in the rear. The intent was to reduce unsprung weight.

Suspension and Ergonomics

In the suspension department, there’s more newness, including a new dark navy blue ti coating on the lower tubes of the Showa forks for reduced friction and improved performance. The upper legs on the forks have a new shape, and a Kashima inner coating designed to further smooth the fork action.

The Showa forks on the KX250F are about as factory-looking as you'll find on a showroom stock bike, with their ti coating for the lower legs. Click for a larger image.

The triple clamps are…you guessed it, new, and have a reduced offset, and a new upper clamp. They also wrapped the forks with a new guard, which wraps nearly all the way around the lower legs.

The Showa rear shock has a new layout, again with the Kashima internal coating, and features a 50mm piston.

The overall bike is slimmer, including the seat (which uses a firmer foam), and a set of Renthal alloy bars.

There are a host of other new goodies, like the new resin skid plate, new chain guide, wider 50mm footpegs, a new seat design, new radiators with built-in braces, and all-new bodywork. In the past the shrouds and side panels were two-piece items that were bolted together, but now both the colors are molded together.

Side plate? Or mini-skirt? We actually like the new plastic, though three-digit numbers might be a bit rough to do.

So as you can see, about the only thing old on this bike is that it’s still green, and it’s still a Kawasaki…unless you want to bump up a couple hundred bucks from the $6,499 retail, and go for the all-black Monster Energy Special Edition. Check with your dealers now.

All in all, it looks like quite the impressive effort, with far more than the average number of year-to-year changes. With the success that the Monster Energy Pro Circuit Kawasaki squad has had with this bike in the past, we’re looking forward to seeing what happens with it after Mitch and the rest of his crew work some of their magic on it for the ’09 season.

Check the link to the photo gallery and video (above), for more on the all-new Kawasaki KX250F.