Cobra's Killer
COBRA'S KILLER
RACE WATCH
David Vuillemin's Yamaha YZ250 P1
IT'S BEEN A WHILE SINCE I LAST RODE a factory Supercross bike. Say, 1993 and Jeremy McGrath's championship-winning Honda CR250, to be exact. That red rocket was way too stiff and way too fast, a hell of a lot more machine than I could ever handle. Perfect for MC, not for me. So I never really felt like I was missing out by not riding any more works SXers.
Then comes this opportunity to see what Yamaha has been doing to win so many Supercrosses of late. David Vuillemin, nicknamed “Cobra” for his lanky, arms-flapping riding style, has struck with an obviously potent package of personal confidence and solid machinery. His YZ250 is oddly enough one of the most stock-looking factory bikes on the startline, but don’t think for a minute it isn’t trick. Every nut, bolt or screw is titanium, as is the subframe. Light! The engine has five speeds but only four are used, the ratios specific to Supercross, where the bike is in second
gear nearly all the time, third through the whoops and on the start straight. Never in first, rarely in fourth.
Cases and cylinder are standard per AMA rules, but the crank, carburetor and ignition are all special or heavily modded. The carb is a works magnesium Mikuni with a throttle-position sensor and a powerjet. Between the
carb’s TPS and a transmission-gear sensor tied into the timing, there’s an ignition curve for every situation.
Wheel hubs are magnesium with works Nissin brakes. Suspension is works KYB with settings developed by Vuillemin and Yamaha U.S., the spring rates being a bit of a secret, as is the triple-clamp’s offset. As Yamaha Motorsports Racing Division Supervisor Steve Butler said, “We’d like to know what Carmichael, Pastrana and LaRocco are running, too...”
Many of the carbon-fiber parts are GYT-R Yamaha catalog items available to customers, as is the odd combination of an FMF pipe and a Pro Circuit muffler-hey, whatever works!
Riding Vuillemin’s YZ was a complete shock. I was expecting a super-stiff bike with beastmaster power delivery. Instead, the Yamaha was actually quite plush. Watch Vuillemin on TV; he’s very light on the bike, even when landing after killer triples. His engine mirrored the stock YZ’s excellent crispness on bottom, but when it came alive, it had exponentially more pull, revving out to insane power levels! How Vuillemin rides at such high rpm I’ll never know.
Mega-motor aside, the biggest difference in feel from a standard bike is in weight. At 218 pounds, the factory YZ is light, easily 10 pounds under a Stocker. It feels more like a 125 than a 250, especially in flickability. It felt like I could just throw it out from underneath myself at any moment. And it was awesome how well this bike slammed through whoops, actually liking it better the more you accelerate. This is maybe the perfect Supercross setup, save for Vuillemin’s geeky lever position-he likes his clutch and brake controls pointing to the sky. Hey, again, whatever works, ’cause it’s obviously working very well.
Jimmy Lewis
