Now I'm no supercross rider, but I'm just like you in the stands: I wonder what it would be like to be out there on that track. I still wonder what it would be like to ride one of those bikes (I'm lucky, I've done that), and I also wonder what the difference is between privateer and factory-level equipment. No, not on the stand, where the trickness and exponential dollars spent on factory equipment is obvious, but out on the track where it's all about what the rider's feeling.
You can find Jiri Dostal's bike under the Wonder Warthog tent at any supercross, but I found it at Perris Raceway. It's a far cry from a supercross track but it has some jumps, OK? The bike was clean and ready for the upcoming San Diego SX and I got to spin a few laps on it.
Easily one of the best KX450s Jimmy Lewis has ridden, it still didn't make him want to race supercross.
The first thing that struck me about this bike was the suspension. Typically the stiff-as-a-board ride on these SX bikes is so firm that they bounce and rattle across every ripple. This Enzo-equipped KX-F was super plush, almost like an off-road bike with a thickly padded seat. Like there was three inches of mush built into the travel. I didn't feel the ripples. But hit a jump face and it turned into the supercross suspension I know, and held the bike up in the stroke and made launching seem easy. You could slam into the face harder than you'd think and still fly off level. And since you're going farther, the landing was handled with ease. It reminded me of David Vuillemin's factory YZ250 I rode a few years back. This suspension is impressive and available through Enzo, which further leads me to believe it is the ability of the rider to tell the tuner what he wants, not just "factory suspension" that makes a bike work.
The engine was also very ridable and had a smoother-than-expected nature to it. It would really come alive in the mid and rip up on top, more than any human I've ever known would need on a supercross track, with the exception of the start straight. Truthfully, I liked the power and would love this setting outdoors, but even Jiri was looking for a bit more hit and snap off the bottom. There was a definite hit a top rider could use in supercross further up in the R's, but I wasn't able to control that much power. I don't need to fly that far!
And the last thing I felt was that this bike was lighter than I remember a KX450 feeling. I didn't see any evidence of trick titanium or anything that would explain this, so it must've been the 22mm-offset triple clamp, which has a way of making machines feel more feathery. It worked for Honda, and Jiri's bike was getting away with it without a steering stabilizer. The bike showed attention to detail and a prep that would make most riders feel it was better off in the living room than the garage, and I felt bad getting it dirty. Now go make some mains!
Parts List
MDK Speed: www.mdkspeed.com; 408.295.7437
Porting/head work: $499
Copper seats: $500
Carb boring: $285
Valves: $349/pair
Springs: $249/set
CP piston 13:1
Disassembly/assembly-motor out of bike: $285
Enzo Racing: www.enzoracing.com; 714.541.5218
Suspension revalve/springs: $795
Kashima coating and anodizing: $550
Dubach Racing Development: www.dubachracing.com; 877.382.2241
Stainless/carbon-fiber exhaust system: $679.95
Applied Racing: www.appliedrace.com; 800.853.0555
22mm-offset clamps: $395
Bearing/stem set, installed: $89.90
Wiseco: www.wiseco.com; 800.321.1364
Clutch basket (R&D): $230
ASV Inventions: www.asvinventions.com; 714.861.1400
C5 clutch perch and lever with hot-start: $155
Rotator clamp: $25
F3 brake lever: $70
CDG Technology: www.cdgtech.com; 503.243.4451
Titanium fasteners-body kit: $300
RK Excel America: www.rkexcelamerica.com; 760.732.3161
GB520MXZ chain: $93.31
Excel rims $362.74
Tamer: www.prowheelracing.com; 360.691.6459
The Original holeshot device: $69.95
Vortex Racing: www.vortexracing.com; 800.440.3559
Sprockets
Decal Works: www.decalmx.com; 815.784.4000
T4 semi-custom graphics kit-complete: $199.95
T4 number plates/airbox sides: $69.95
Cycra: www.cycra.com; 800.770.2259
KX-F front performance fender: $18.95
KX-F Powerflow rear fender: $24.95
Primal Stealth hand shields: $34.95
Brake line cable guide: $7.95
SDG USA: www.sdgusa.com; 800.743.3734
Standard complete seat with dual-stage gripper cover: $103.99
Universal Engineering: www.universalmotocross.com; 714.861.1490
Atlas bar: $100
Monocoque stand: $100
Dunlop: www.dunloptires.com
D745 120/80-19 rear
D745 F 90/100-21 front
01 Vortex sprockets look good enough for a custom Harley...if they had a chain. | 
02 Dubach Racing knows how to put power to the ground and meet sound. | 
03 MDK Speed has an awesome package but is still looking for more SX hit. |