2010 Kawasaki KX450F Long Term Wrap Up

It’s with great sadness that I write this, but I am no longer in possession of our 2010 Kawasaki KX450F motocross bike, recently returning it following nearly a year-long love affair. To say I had become attached to Team Green’s premium motocrosser would be an understatement; the big KX proved to be a fun, fast, and stone axe-reliable dirt bike. To find out how the bike performed in all of our tests check out our 2010 Kawasaki KX450F First Ride, 2010 Kawasaki KX450F Comparison and Kawasaki KX450F Mammoth MX Race Project.
 
After roughly 12 months of riding we had accumulated nearly 52 hours on the green machine. We rode it extensively at a variety of different motocross tracks throughout Southern California. We also raced it more times than I can remember, at events like Troy Lee Design’s Day in the Dirt, Mammoth Motocross, REM Motocross series and the Vet-X series. Since we’re also keen on off-road riding, we brought it out to the sand dunes of Glamis not once, but twice. We also rode it a few times at Ocotillo Wells and let our friend and professional motocross racer, Scott Simon, train on it for a few weeks prior to starting his full racing season in South America.

And this, in essence, is one of the best attributes of the KX450F - its versatility. It proved capable in each off-road environment from the motocross track, to the dunes and the desert. Despite being one of the larger 450s dimensionally, it is actually surprisingly nimble for a 250-pound dirt bike. It’s agile enough for use at tighter tracks that usually favor 250Fs, such as SoCal’s Piru and Starwest, yet equally as capable at the more open circuits of Racetown 395, Glen Helen, Pala and the now defunct LACR.

The layout of the cockpit and the spatial relationship between the footpegs, seat and handlebar also work well for average and plus-sized riders. Other than flipping the handlebar mounts to move the bars slightly forward we didn’t have to change anything besides the hand grips. Equally as versatile is the power and throttle response of the engine, courtesy of the Kawasaki Fuel Injection Calibration Kit. With the tuning tool and a Windows-based computer you can adjust the engine’s powerband based on track conditions or rider preference. For motocross our preferred map was either the Hard Terrain or Advanced Ignition setting (except for Mammoth, in which we used a special Team Green Mammoth map due to elevation), and for riding off-road in Glamis we utilized the hard-hitting Soft Terrain map.

Despite our year-long continued abuse, the Kawasaki still performed perfectly right up until the day we turned it in. Sure the plastics, wheels, radiators and engine side covers were well-worn, yet all the vital mechanical components, including engine, frame/swingarm, suspension and brakes were in great condition.

The engine felt tight, retained a high level of compression and fired right up on the first or second kick. Power-wise, it felt like it ran identical to the day we first rode it. Part of the reason that it feels so fresh is that we were meticulous about our oil and filter changes every five running hours. This is three-times more frequently than what the manual recommends, but, as they say, better be safe than sorry.

Even still, five hours is a considerable amount of engine running time and we were able to get between 5-10 rides at the motocross track or a full-day of riding at Glamis in between oil changes. We used various brands of oil in either 10W-40 or 10W-50 weight, while the piston was replaced and valve clearance inspected at 37 hours (all valves were in-spec at the time).

The transmission didn’t feel loose and we never experienced any shifting gremlins. We went through three set of plates and springs but the clutch operated smoothly and didn’t require a new basket. One of the things we like most about the clutch is that we never encountered any type of fade during prolonged use. The packing in the stock muffler slowly wore out and started to become annoying around the 30-hour mark. We eventually replaced it with an FMF Factory 4.1 slip-on muffler at 37 hours.

The stock suspension performed well for the first 15 to 20 hours of use. After that we noticed that the damping performance of the shock started to degrade followed shortly after by the fork. We changed the oil in both components, recharged the nitrogen in the shock body and damping performance was restored. We eventually had the fork and shock serviced and re-valved by RG3 (for 170 pounds – 180 pounds Novice / Intermediate rider, spring rates remained the same) at the same time the motor was getting freshened up. With another 20 hours on the RG3 setup, performance has remained consistent ever since. Chassis components like the steering head and shock linkage, moved freely and didn’t feel like it was binding or worn out.

We’re on our fourth set or rear brake pads (the latest of which were Ferodo SinterGrip SG-plus pads), which could be attributed to how hard some of our testers work the back brake. Conversely, we got a fair amount use from the front pads and are still working through the second set (also Ferodo). Brake fade was never a problem and we bled both the front and rear braking systems once at around 25 hours just for general preventative maintenance.

Other wear-and-tear items included the chain and sprockets, which were long-overdue for replacement at 37 hours. Rather than using stock components again, we sourced a pair of Renthal sprockets and chain in OE sizing. Also installed were a new plastic chain block and front buffer. A total of five sets of tires from Bridgestone, Dunlop and Pirelli were consumed, our favorite was perhaps the Pirelli Scorpion Mid-Hard front and Hard rear tires (stock sizes), with them providing a good balance between grip and longevity. Thankfully, we also didn’t suffer any major crashes (knock on wood), so the only damage encountered during the Kawasaki’s life at MotoUSA was all minor, including bending and snapping a couple brake and clutch levers, plus a few re-aligned handlebars for good measure.

All said and done it cost nearly $4000 to keep our KX in perfect shape for one year of constant riding. While it certainly isn’t chump change, you’ve got to pay to play. And that’s exactly what we did with our KX450F.