If you think about it, this is really the first Suzuki RM-Z250. After an industry partnership with Kawasaki that had both companies adopting nearly identical 250Fs as their own for the last few years, Suzuki has finally designed, engineered, tested and built a new motocross baby. And man, does it scream.
This is the time in the new-bike story where we go through the new parts, updated pieces and recently bolded new graphics. And Suzuki's newest RM-Z has plenty to talk about. Let's start with the frame. Well, it's aluminum, and its existence makes steel-framed motocross machines nearly extinct. The smaller RM-Z's frame is a carbon copy of the RM-Z450 unit's, just tweaked and tuned to fit the 250cc motor and the handling characteristics of a smaller-bore thumper. Other frame and handling components are also shared or influenced by the yellow 450. The 250's swingarm, fork and rear shock are all identical units to those on Suzuki's big bike.
Tucked inside the alloy skeleton and 450-proven framework is an updated 250 motor packed with powerful modifications and improvements over all the previous RM-Z250 models. Most notable in the mod department are revised intake and exhaust ports, an updated cam profile and modified combustion-chamber milling-all executed to boost top-end, high-rpm performance. Suzuki really went to town tuning its small-bore four-stroker's broad power delivery with an emphasis on overrev-and that's obvious in the bike's effort to speed the fuel in, squish the tar out of it and blow it up as efficiently as possible. But don't worry, Suzuki didn't forget about the bottom. To ensure a responsive bottom-end, the RM-Z team went the conservative route and kept a 37mm carburetor onboard to keep the bog-monsters at bay.
There are other small updates and improvements to the RM-Z line worth mentioning as well. The control department now mimics the rest of the RM lineup, with a Renthal taper handlebar and a new dual-gripper seat cover. Finally, there's one very cool improvement to the RM-Z: larger radiators behind revised, free-flowing radiator shrouds that boost cooling a claimed 20 percent. As we've boiled plenty of RM-Zs in our day, this is something we're really excited about.
Besides studying everything new and improved on the '07 RM-Z250, we've been riding it a ton. And this is one yellow bike we're literally tweaking out about.
First, the improvements engineered by Suzuki's motor-madmen are insane. From our initial test session we knew something was unique about the new RM-Z. To the delight of our test-rider's wrists, we noticed a throttle response that came on quick with deep, torquey power that wouldn't, couldn't and didn't want to shut off. After our introduction to the machine at the rocky and fairly wide-open Zaca Station MX Park (www.zacastationmx.com), we immediately went in search of longer straights and deeper ruts to tax the new Suzook's powerplant. We found exactly that at Hesperia, California's Competitive Edge MX Park (www.ridecemx.com). The track is a 450's dream, with deep loam and uphill straights that weed out the weak and short-geared bikes quickly. It's a horsepower track that makes 250Fs seem boring. That is, most 250Fs. This new RM-Z isn't most 250Fs, though. No, it's is a torque-tractor with a gear-stretching mid-to-top pull that will impress out of the crate. The low-end power is radical, too. It's a sweet combo of chug and rev about which we are still giddy.
What we found when we railed around is this: The RM-Z250's motor will easily pull every gear in the box and could almost use another speed. If ever an MX bike needed overdrive, this is it. It's a blast to ride because it doesn't really flatten out anywhere. Soon we'll line it up against some bottom- and top-end-specific bikes to see if it can bridge the gap in a heads-up fight. So far, the future of the little Suzuki is bright.
Almost as impressive as the motor is the handling. Suzuki did quite a bit of homework when setting up this bike. When we first rode it, we experienced a severe push in corners that had us considering rebound adjustments or even moving the fork in the triple clamps. However, we checked our clicker settings with stock and, to our surprise, found out they were way off. We dialed them in to the factory settings and were happy again. The bike was great but still not cornering with the same Suzuki prowess we expected. But after we cranked the sag to an even 100mm, the bike came alive. Cornering woke up immediately, and the bike kept its straight-line stability in check as well. When you can leave a bike at stock settings and simply adjust the sag to a rider's weight, you have a huge advantage-one Suzuki will take directly to the 250F fight.
The newborn Suzook is quickly becoming the surprise of the season among our testing crew and staff members. But it really shouldn't be. After all, the RM-Z is the last one to arrive at the modern 250F table and has undoubtedly learned from its own and the competition's triumphs and mistakes. The RM-Z is engineered just right with a definite purpose and highly effective result. We can't wait to see if its new identity stands up to the other attention-hungry bikes at this year's shootout.