First Test: 2010 Suzuki RM-Z450 – Dirt Rider Magazine

Suzuki has received a fair bit of attention due to the fact that neither of its major motocross bikes made it into Dirt Rider shootouts this year, and we’ve received quite a few queries from Suzuki fans as to what the deal is with Big Yellow. Both of Suzuki’s flagship moto machines are, in fact, alive and well, and as of now we’ve finally been able to give the 2010 RM-Z450 a shot. Here’s how it all breaks down:
Although relatively unchanged compared to the previous model year, Suzuki did apply several revisions to the 2010 RM-Z450 in order to fine-tune the performance of the bike and fix a few minor issues from ’09. At the top of the list of changes are tweaks to the bike’s fuel injection, as the throttle movement has been flipped around so that the butterfly valve now opens in the opposite direction to give the response a smoother feel. There are now two preprogrammed EFI map settings-one for standard conditions and one for higher humidity (leaner)-that are accessed via a coupler under the number plate. Inside of the motor, Big Yellow has come up with new intake and exhaust cam shapes, which are designed to boost power. Additionally, the RM-Z has a reshaped intake tract for more power down low, as well as softer exhaust valve springs. The cam-chain tensioner has been redesigned for decreased vibration, and the kickstart lever has been slightly modified as well. On the chassis side of things, minor portions of the RM-Z450′s frame were altered to provide better balance and flex. The frame’s headpipe was increased in length by approximately 9mm for added rigidity, so call it a new frame. The spring rates for the suspension were cranked up just a tad in both ends. While the sum of these revisions don’t add up to a drastically altered bike, it’s clear that Suzuki didn’t just slap new decals on its ’09 RM-Z and call it a 2010.Perhaps the one benefit to receiving this bike so late is that we had already ridden everything else, and as such it was fairly easy to distinguish the various character traits of the Suzuki to see how they fit into the hyper-competitive 450cc class. The first major highlight-something that jumped out at nearly every tester by the end of their first session on the bike-is the RM-Z450′s superb power delivery. Whereas some of the other bikes in this class feel as though they are shoving power down your throat by the fistful, the Suzuki serves you power like a well-trained waiter pouring a glass of fine wine. Is it mellow? To a degree, as there isn’t any violent hit to speak of when you twist the throttle from a slow roll. But this 450 is far from wimpy, and you can certainly tell it means business when you get on the gas. A strong low-range pull steadily becomes a meaty mid that seems to last forever, while the top-end continues further than that of any previous RM-Z450s, which is a marked improvement in our book. Sure, the bike will sing up top if called to, but we don’t think there’s any reason not to ride the bike in the crisp upper-mid range. At this rpm and in the revs leading up to it, the usable acceleration translates directly into good traction, predictable shifting and pure ease-of-use. You can easily stick the RM-Z into third gear and do an entire moto while hardly shifting or touching the clutch, something that is a blessing toward the end of a long, tiring moto. The well-tuned EFI ensures there aren’t any bobbles off idle, and the altogether usable powerband was a fine fit for testers of all abilities.

When kicking the RM-Z450 over, no magic is required: The EFI has good starting sense and doesn’t require much effort on the part of the pilot. Even at full-on race temps, the right-side hot-start was all that it took to get the bike going. Clutch and shifting action were both solid on the bike, although as mentioned these aren’t exactly high-use components of the RM-Z. In keeping with what we’ve seen on this bike’s off-road counterpart, the RMX450Z, the RM-Z has a pleasant exhaust note and doesn’t sound too loud to the spectator or the rider, though you can certainly tell from the sound that this was designed to be a motocross bike.As was the case with the 2009 RM-Z450, the new Suzuki has definitely earned a black belt in the ninja school of cornering. Whether it’s rutted or flat, off-camber or level, traction-packed or greasy slick, there isn’t a turn type that the Suzuki doesn’t like. You can brake late and push the bike into inside ruts or outside berms at the last minute and still make your line, while the machine stays planted throughout and while exiting the corner. Part of this is due to the ergonomics of the machine, which let the rider get right up on top of the tank in turns while still leaning the motorcycle over with relative ease. One of our lighter test riders preferred to soften the rear suspension slightly to allow the RM-Z to settle more in corners, but other than that we didn’t have a single issue with the way this bike turns.With the revised spring rates for 2010, the Suzuki is slightly stiffer than before, with a Showa fork that features good, albeit harsh initial feel and decent bottoming resistance for average-weight riders. We played with the fork clickers quite a bit, and several of our testers ended up liking them two clicks stiffer, providing more stability when charging into hard hits. The rear suspension is likewise adept at absorbing chop and big G-outs, as only our fastest pros asked for more damping in the rough stuff. We did have one small issue with the rear shock, though, when the rebound adjuster failed to turn out further than 14 clicks. Suzuki sent us a new shock which had 19 clicks, and we used the extra ones. We hovered at 14-16 clicks out. In combination with the shock, the entire suspension setup provides an excellent combination of balance and stability, giving the Suzuki a good all-around feel.Another thing that’s obvious on the track is that the RM-Z carries its weight extremely well. The bike feels light, causing some test riders to compare it to the lightweight Suzuki feel of old, but without the instability issues. You can turn this bike in the air, aim for an outside rut and put the big motorcycle precisely where you want it. It’s not difficult to get the front wheel off the ground, and the front end is so light that it can sometimes be difficult to gauge the bike’s attitude on jump takeoffs, especially when compared to some of the heavier-feeling bikes in the class. This isn’t so much an instability issue as it is an inconsistency, but a few of our test riders remarked that they felt as though the RM-Z didn’t jump the same every time. We’ll call it pro-level handling.In terms of complaints, the only major beef raised by our test riders was that some-meaning seasoned pros and slightly heavier riders-wanted more aggressiveness out of the powerband. While this test was conducted with the bike completely stock, we have begun testing aftermarket exhaust setups on the RM-Z (for our upcoming pipe comparison) and can say that it’s relatively easy to alter the 450′s character with a simple bolt-on exhaust. As you’ll read, more hit and increasingly aggressive deliveries aren’t at all difficult to obtain with the right mods.

The big question: How would this bike have done in our 450cc shootout? While we can’t say with certainty without retesting everything back to back, odds are the RM-Z450 would have been a strong contender when compared directly with the other big MXers. It may not have the out-of-the-box performance of the Yamaha (though it might just act lighter), the outright aggressiveness of the CRF450R, the bark of the KX450F or the plushness of the KTM. But the Suzuki is a well-rounded package that translates into great results for a wide variety of riders. It’s unfortunate that this machine didn’t come out earlier, but that doesn’t mean you can’t enjoy the benefits of this solid MXer as it sits now. Suzuki may have been the last one to the dance with the RM-Z450, but if you like Yellow, it was well worth the wait.Specifications: 2010 Suzuki RM-Z450
MSRP: $8,099
Claimed weight: 247 lb
Actual weight (tank full): 251 lb
Seat Height: 37.2 in.
Seat-to-Footpeg Distance: 20.8 in.
Footpeg Height: 16.4 in.What’s hot!

• Great delivery!
• Killer ergos make for consistent cornering.
• Balanced suspension with excellent bottoming resistance.
• Spot-on EFI tuning.
• It’s finally here!

• Not the most aggressive animal in the pack.
• A few testers felt that the lightweight feel translated to inconsistent airtime.
• A shock issue points to possible reliability gremlins.

Opinions

Ryan Orr
5’9″/165 lb/Pro
There are many things that impress me about the new RM-Z450. Two really stand out. The first one is the motor. It is very easy to ride! The delivery is amazing! The bike has a lot of horsepower without that “yank your arms out of their sockets” hit that can wear you out. Suzuki was also able to cure the gnarly rev cut that hindered the bike in 2009.The second thing that stood out to me was the cornering. It’s hard to believe the already amazing-turning machine could actually turn any better than it did in ’09 but it does. It doesn’t matter if the turn is flat, tight, open, sweeping, rutted, hard-packed or loamy. This bike sticks, holds tight and allows you to corner on a dime. I think a lot of the cornering comes from the comfortable ergos of the bike. The bike is very comfortable and is easy to move around on. The RM-Z is also very nimble and feels very light weight. This makes the bike feel very responsive to making line changes along with feeling super light and responsive in the air.Jesse Ziegler
5’10″/175 lb/Intermediate
I was very impressed with the 2010 RM-Z450. Right from the beginning the power came on strong. My little wussy sissy hands and forearms pumped right up at Glen Helen trying to hold on to the yellow beast. Power on all 450s sort of does that, so I guess the thing that impressed me the most on this bike was the light, easy-to-move-at-any-time handling. Glen Helen was rough with multiple lines but I could bob and weave my way anywhere. Wheelies out of turns were controlled and super fun. And I could set the pitch of the rear tire and change directions at any time. It’s more than great cornering. This bike makes the corner you want, wherever you want it. Unfortunately, the too-common Suzuki build/component quality heebie-jeebies crept in right away with our shock clicker going on the fritz. And more parts look cheaper on the Zook than any other brand. I’ll need some suspension work to get it to feel controlled and to stop bottoming out, but I love the motor and handling…what a fun ride!Chris Barrett
6’1″/185 lb/Pro
I was pumped on last year’s RM-Z450; the bike handled great, had decent suspension and would have been a competitor but…it had a horrendous rev-cut that would sign off the power instantly when overrevved. But for 2010, the problem has been solved.Now this puppy pulls for days. The RM-Z has a very smooth, seamless power band with decent bottom, strong mid to top and great overrev. The motor runs clean and is easily controllable.The suspension worked decent but was a little too free feeling and could have used more of a controlled feel. The fork had a bit of deflection through the chop when the front end was light and bottomed on the bigger bumps. The shock was very planted under acceleration but had some kicking through fast chop and braking bumps. I was happy with the sag set around 105-106mm because that really balanced the bike out and settled down the front end; it also improved the already amazing cornering and still kept the rear end planted under acceleration.