WE RIDE RYAN DUNGEY’S NATIONAL CHAMPIONSHIP SUZUKI RM-Z250:

March 7, 2010
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Sometimes moments pass so fast that you don’t have time to muse on them. The 2009 season was like that for Ryan Dungey. He not only won the 250 West Supercross Championship, but the AMA 250 National Championship and the 450 class at the Motocross des Nations.  Rather than let Dungey’s triumphant year speed by in a blur, MXA decided to take the bike he rode to two AMA Championships for a spin. Here is the test of Ryan Dungey’s Championship winning RM-Z250.

The greatest advantage of a factory ride over a production bike is the availability of different options and the resources to customize the bike to suit the rider and the conditions. And there is the common misconception that the quality of the individual components is far superior to production. It’s not that the factory parts are made better, it’s that they are custom made.

A quick glance at Team Suzuki’s RM-Z250 isn’t all that impressive at first. Suzuki does a lot more 450 racing on the world stage than 250 racing and, as a result, there are more exotic RM-Z450 race parts than RM-Z250 pieces. The special RM-Z250 parts that come from Suzuki of Japan are either performance options (cams, subframes, valves) or lightweight titanium or magnesium parts.

WHAT THE MXA WRECKING CREW HAS LEARNED OVER YEARS OF RIDING WORKS BIKES IS THAT THE BEST FACTORY BIKE ISN’T NECESSARILY THE MOST EXOTIC. CARE AND THOUGHT ARE MORE IMPORTANT THAN FLASH AND FINISH.

What the MXA wrecking crew has learned over years of riding works bikes is that the best factory bike isn’t necessarily the most exotic. Care and thought are more important than flash and finish.

Stepping up to Team Suzuki straight from the amateur ranks, Ryan Dungey has benefited from the testing and racing time aboard his Makita/Rockstar Suzuki RM-Z250. Ryan’s three seasons of pro racing have not only been successful, but also dramatic. In 2007, he learned the ropes and earned the AMA Rookie of the Year award. In 2008, Dungey fought for championships, but finished runner-up in both the 250 indoor series and 250 outdoor series. It was rightly assumed that 2009 would be his final chance to earn a number one plate before moving up to the premier 450 class. Dungey finished first in the 2009 250 West Coast Supercross series and the 250 National Championship. Before the season got into full swing, Dungey announced that, win or lose, he would say goodbye to his 250 after the final round at Steel City. In fact, Dungey immediately switched to an RM-Z450 for the Motocross des Nations.

Winning the 2009 AMA 250 National Championship was the culmination of Ryan Dungey’s 250F career. With Ryan moving up to the big boy class, this is really the last opportunity for the MXA gang to test Ryan Dungey’s National Championship-winning 2009 Suzuki RM-Z250.
 


We noticed that his clutch lever is a little farther down than most, while his brake lever is standard (although his mechanic informed us that its precise position varies day to day).

SHOP TALK: BREAK IT DOWN

Here’s what we found out about Ryan’s RM-Z250 in the engine department: The cylinder, in accordance with AMA rules, is production. The head was modified by American Suzuki. The crank and cams come from Suzuki of Japan, and the piston is from CP Pistons (via Pro Circuit). The transmission is production-based, but with special attention. The gearbox components go through a polishing process, and there is a different star gear that trades a bit of efficiency on downshifts for smoother upshifts. Clutch components are from Hinson.

Other components include the Keihin carburetor, NGK spark plug, Pro Circuit exhaust, Twin Air filter, Tag Metals sprockets, D.I.D chain, Maxima oils, and works radiators and ignition from Suzuki of Japan.

In the chassis department, we were able to dig up some secret info on the championship bike. The wheels are comprised of magnesium hubs from Suzuki of Japan, along with Excel rims, stock spokes and a special works axle. For stopping power, Dungey’s Suzuki utilizes works Nissin brake pads, master cylinders and calipers. The oversize front brake rotor, rear rotor and brake clevis are works parts from Japan.

Dungey’s forks and shock are RG3-tuned Showa A kit parts, and the linkage and triple clamps are from Suzuki of Japan. A notable point on Dungey’s shock setup is a common bleed system allowing oil to flow freely on compression and rebound strokes. Where a traditional shock uses a check valve to isolate the two, Dungey’s works shock uses an open bleed design.


Thanks to his personal choice, Ryan Dungey has a much broader and more usable powerband than most of the bikes in his class (and a couple of 450s guys too).

Pro Taper handlebars and grips, One Industries graphics and seat cover and Bridgestone tires complete the package. The Bridgestone rear tire was actually a unit that became available to race teams at the beginning of the year. It consolidated two different Bridgestone hardpack tires into one. It was originally designed for Supercross, but became the tire of choice at tracks with loam over a hard base, like the final round at Steel City. Dungey’s seat foam, levers, skid plate, titanium footpegs and mounts, and other titanium hardware all came from Suzuki of Japan.

TEST RIDE: PIN IT TO WIN IT

When MXA tests a factory bike, generally the rider’s mechanic and maybe the team manager will accompany us to the track to answer our questions and spin wrenches on the bike. On this occasion, Ryan Dungey decided to come along so he could turn some practice laps on his RM-Z450. Ryan is one of the nicest guys on the circuit and offered invaluable insight into his bike.

According to Ryan, the first thing he checks on the bike are the positions of the handlebars and levers. We noticed that his clutch lever is a little farther down than most, while his brake lever is standard (although his mechanic informed us that its precise position varies day to day). From there, Ryan said tire and suspension setup are very important to him, and he often makes changes throughout the day (when the conditions suit it). Ryan has a notebook full of gearing, cam, flywheel and other engine mods that might help him at a specific track or style of dirt.

DUNGEY’S BIKE WAS COMFORTABLE AND CONFIDENCE-INSPIRING. TEST RIDERS HAD NO PROBLEM JUMPING THE BIG JUMPS?OR ATTEMPTING TO JUMP THEM. DUNGEY’S STIFF SHOWA WORKS SUSPENSION SOAKED UP OUR SHORTCOMINGS, ALTHOUGH WE DID LEAVE A NICE SQUARE SPOT IN HIS FRONT RIM (HE DIDN’T NEED IT ANYMORE, ANYWAY).

On the track, the MXA test riders were immediately impressed by the roll-on power. Where many pros might sacrifice a broad powerband to maximize every ounce of horsepower on top, Dungey chose to spread his power out. His Suzuki makes solid power in the low-to-mid range. It should be noted that through the midrange, Dungey’s RM-Z250 left the stock RM-Z250 in the dust. Ryan’s engine revs freely and pulls strongly through the middle and into the top. Eventually, the power flattens out and test riders had to shift in order maintain the blistering acceleration.

Short shifting, albeit not too soon, was like reloading a cannon. Each shift, when accomplished on the torque curve instead of at peak rpm, would result in an instantaneous rush of acceleration.


Unfortunately, Dungey won’t get to run his number one motocross plate.

The Nissin brake caliper and oversize front rotor is a thing to be loved and feared. The brake can be fed in at the entrance of turns to stop the bike on a dime. It has to be respected though, because an accidental twitch of the front brake has consequences. All in all, the brakes allowed testers to go much hotter into turns, while the works forks allowed them to do so while maintaining accuracy over braking bumps. The shock has a very light feel on rebound and an exhilarating free sensation.

Dungey’s bike was comfortable and confidence-inspiring. Test riders had no problem jumping the big jumps?or attempting to jump them. Dungey’s stiff Showa works suspension soaked up our shortcomings, although we did leave a nice square spot in his front rim (he didn’t need it anymore, anyway).

WHAT DO WE REALLY THINK?

In theory, the razor-sharp turning RM-Z250 chassis should be the best starting place for a serious race bike, since suspension and power are the easiest to fix. Not surprisingly, this is the recipe that Suzuki used on Dungey’s RM-Z250. Dungey’s time on the RM-Z250 was well-spent, and judging by the powerband of his 250F and the success he has already had on the 450, we think it’s a safe bet that Ryan will feel right at home on his new RM-Z450.

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