2006 Kawasaki KX450F Dirt Bike - Dirt Rider Magazine

The KX-F keeps on chugging. The moto machine has taken some victories and a few cartwheels as well during its summer vacation. So after a good crash, the first order of business was to replace the top-clamp bar mounts, which were tweaked. We opted for Kawasaki's optional oversize ones so we could use a Fasst Company Flexx bar. While dialing the controls (now all a little bent), we chose to go the highest road with Sunline/ARC's complete CNC Axis clutch perch and the ARC CNC front brake lever. They have a small lever diameter and great feel, plus the clutch leverage ratio is changed to make it an easier pull. While we were at it, we replaced the leaky fork seal and changed the other seal as well as the outer chamber oil on both legs. Now the front end is not only very expensive, it is sano, too.One of my constant tuning issues has been to smooth out the delivery. I found the best tool for that so far. The MT Vortex ignition and its 10 maps get the job done-and then some. I can switch between two maps with the handlebar-mounted switch. The boosted stock curve and traction curve are my favorites. My Pro Circuit pipe was getting loud and needed packing, so I switched over to a Big Gun EVO with the quiet core. Its fasteners needed constant attention due to the excessive heat (though it did test at 92.7 decibels at the Dirt Diggers Hangtown National Amateur Days sound test, one of the quietest four-strokes there!), and it finally stripped one of the end-cap attachments. My new favorite for sound and power is the Leo Vince X3 full system from our 96-decibel pipe comparison (December '06).Tire choices have been simple for the plain fact that I mounted a set of Pirelli Scorpions and they wouldn't wear out. The hard front and the midhard rear took the summer-baked hardpack, performed great and looked solid after eight hours of moto. They finally gave way to a set of Dunlop 756 Race Replicas I needed to test.About the only problem with the bike has been the clutch and the riders adjusting it too tight, using it to control the power and getting it hot. Then it starts to slip and the plates take a beating. We had to reinstall one of the older stock clutches in an emergency to be able to ride it after another rider hadn't realized his mistake (torture). When the clutch cooled down, it dragged and never had its solid bite, as the plates were cooked from the constant slipping.Next up is a teardown to see how the KX is holding up and whether it really needs a rebuild after a year of action.Running Tally #2

Hours on Bike: 40
Modifications: $3042.40
Fasst Company Flexx Bar: $299
Sunline clutch perch: $199.95
Sunline front brake lever: $89.95
Vortex ignition: $419
Big Gun EVO R system with Vortex insert: $599.95 (excluded from total)
Leo Vince pipe: $863

Maintenance and Repairs: $476.63 (not including tires)
2 oil changes and 1 filter:
Oil filter: $6
Silkolene Pro 4 10W40: $13.99 per liter
Fork and dust seals (total): $50.24
Bar clamps (oversize): $77.28
Dunlop 756RR tires, front, $107.13; rear, $127.22
Pirelli tires, hard front, $81.95; midhard rear, $88.95