KAWASAKI KX250X GP RACE MODS: BEHIND THE BUILD

Kawasaki didn’t try to overthink the KX250X. It’s basically a motocross bike with off-road suspension. In the case of a 250 four-stroke, that’s good; it already has a smooth power delivery that works off-road. Still, there are some things it needs to complete the transformation.

Kawasaki’s KX250X came in considerably less expensive than KTM’s off-road 250 but left the buyer to finish up.

We started off by switching to the white coupler for EFI mapping. Kawasaki delivers the bike with the black (richest) map in place. At first, we did this simply for fuel range. The NGPC races can have you on the track for an hour, so the stock tank was iffy. We discovered we liked the power delivery with the white coupler best anyway, so it stayed even after the 2.75-gallon IMS tank was installed and fuel range was no longer an issue.

The FMF Factory 4.1 Ti/carbon system produced an amazing performance increase and will accept a spark arrestor.

Shortly after getting our test bike, FMF borrowed it for development of a Factory 4.1 exhaust system. They did a great job. It resulted in a dramatic gain where it was needed. The middle-rpm soft spot in the KX’s power is filled in well without any loss on top. In AMA off-road racing out west, 250 two-strokes race in the same class as 250 four-strokes, placing thumpers at a small disadvantage in mass starts. We can’t tell that the KX250X has any disadvantage. It’s a rocket.

The Precision Racing Products steering damper is compact and doesn’t affect bar height.

Robby Bell’s Precision Concepts Chaparral Kawasaki team settled on the Precision Racing Products damper (Precision Concepts and Precision dampers are not affiliated). Precision has been making dampers for ATVs for a very long time. They really are made with a high degree of precision. The dampers are more compact than anything else on the market, and in the case of ATVs, they had to perform a more difficult task. The best thing about the application for the Kawasaki KX250X is that it doesn’t affect bar height. You barely know it’s there. It still totally eliminates head-shake. That’s a must for western racing, although only about half the riders in the GNCC Pro ranks use dampers.

The Impact Moto Peg has an elastomer cushion between the peg mound and the cleat to damp out any vibrations.
Flexx bars have enough give to make a huge difference at the end of a long ride.

Flexx bars are another great item for off-road riding. They have elastomer cushions that take the edge off of sharp impacts. If you ride for hours, you know what happens to your hands and wrists. Flexx bars are the best way to deal with that. Fasst Co. has recently added the Impact Moto peg to its line. This has an elastomer cushion between the peg mount and the cleat to kill vibration. It really works, particularly on dirt roads. A Fly Hard Parts chain and Cycra handguards are the final pieces of the puzzle.

An IMS tank will increase fuel capacity by over a gallon.

When it was all done, we contacted our buddies at BackYard Designs to make the graphics, which need to be a certain spec in the NGPC series. We could complain that Kawasaki didn’t finish the job. But, there’s something to be said for doing it our way.

Ron Lawson has been racing the 2021 Kawasaki 250X in the NGPC Series. Photo by Mark Kariya.
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