2011 SUZUKI RM-Z250 MOTOCROSS TEST: SUZUKI BRINGS THE RM-Z250 BACK FROM THE BRINK

December 9, 2011
Comments off
1438 Views
facebooktwittergoogle_plusredditmailfacebooktwittergoogle_plusredditmail

Q: FIRST AND FOREMOST, IS THE 2011 RM-Z250 BETTER THAN THE 2010 RM-Z250?

A: Yes. How so? A total of 34 changes have been made to the 2011 Suzuki RM-Z250. That’s quite a few updates, considering that in 2010 the RM-Z250 was practically new from the ground up. Last year, the RM-Z250 received electronic fuel injection, an aluminum gas tank, engine modifications, a redesigned aluminum alloy frame, new swingarm and revised spring rates.

Q: WHAT ARE THE MAJOR UPDATES?

A: Suzuki zeroed in on four main areas:

(1) Engine. A new exhaust system has been modified to meet the AMA’s 94 dB noise limit. The intake cam timing and exhaust cam profile have been revised to provide increased performance with lower noise output. The ECU settings have been updated for more linear acceleration and improved over-rev, and the radiator hose routing has been changed from a “T” design to a “Y” design for more efficient cooling. Also, the crankcase breather has been changed to improve flow.

(2) Durability. Suzuki updated the transmission, focusing on wider third and fourth gears. Gearing has also been changed to a 13/49 combination. The RM-Z250 features better lubrication on the center of the clutch and countershaft for more durability, and Suzuki revised the clutch plates for added reliability. The clutch cover features a new rib on the inside of the cover for more strength. Oil capacity inside the engine has been increased from 1000 ml to 1100 ml. The seat cover is now longer lasting, and the kickstarter arm has been redesigned for easier starting. The RM-Z250 front brake comes with a new caliper that features an aluminum piston (in place of the resin piston from last year) and a revised front disc.

(3) Suspension. The 47mm Showa forks have revised valving specs that lessen initial harshness. The rebound setting now offers 11 clicks (the 2010 model only had nine). The forks contain more oil (377cc versus 373cc). The Showa shock features revised valving to complement the new fork settings.

(4) Electrical.
The 2011 Suzuki RM-Z250 comes with updated wiring harness routing. A convenient fuel line cap is also included so that debris cannot fall into the fuel pump during routine maintenance. Suzuki provides two different couplers, which makes changing the fuel map settings simpler. These additional couplers complement the standard setting. The white coupler (leaner) is for higher-humidity conditions, while the gray coupler (richer) is for loamy conditions and sandy tracks.

   
Trade-off: Suzuki traded its awesome low-end power of yore for more midrange and a healthy top. It was a good swap. Surprise: The RM-Z250 benefitted from fuel injection.


Q: HOW WOULD WE DESCRIBE THE 2011 SUZUKI RM-Z250 ENGINE?

A: Suzuki’s updates to the engine performance package were minor. The 2011 RM-Z250 engine is very similar to the 2010 model.

Since the RM-Z250’s inception in 2004 (although the post-Kawasaki/Suzuki alliance year of 2007 is more accurate), the typical RM-Z250 powerband has been focused on bottom-end power. It ruled the roost in the 6000 to 8000 rpm range, but took an Albatross-style nosedive above the midrange. The RM-Z250 engine was very deceptive in that it revved, but the earlier RM-Z250s didn’t have a top-end to speak of.

In MXA‘s view, the optimal 250cc four-stroke powerband should have decent bottom-end to get the bike into the meat of the powerband, followed by an extraordinary midrange that leads into a fire-breathing top end. Decent over-rev is icing on the cake. The RM-Z250 of yore was reminiscent of a firecracker; the bottom-end provided a big spark, followed by a lot of noise and smoke.

The 2011 engine is the complete opposite of the engine that came before 2010. It has excellent midrange and a ton of top-end gusto. No longer can we gush about the incredible bottom-end snap, but we’re not sad. Why? The 2011 RM-Z250 is a competitive 250 four-stroke built for racing (we couldn’t say the same thing about the 2009 or older RM-Z250 engines). Hallelujah! It’s not the strongest engine in the 2011 class, but it’s in the ballpark.

Q: HOW DOES THE 2011 SUZUKI RM-Z250 RUN ON THE DYNO?

A: Maximum horsepower on our 2011 Suzuki RM-Z250 is 37.82 ponies at 11,400 rpm. Maximum torque is 19.91 foot-pounds. The old-style 2009 RM-Z250 engine produced 1.34 horsepower less than the 2011 model. On the dyno curve, the new-version 2011 RM-Z250 jumps above the old-style engine at 7200 rpm and never relinquishes the lead. At 9800 rpm, the 2011 model holds a two horsepower advantage over the old-school 2009 engine. That’s a lot of ponies!

2011 Suzuki RM-Z250: MXA test riders always loved the RM-Z250?in spite of its shortcomings. For 2011, Suzuki finally fixed the flaws in the powerband and suspension. Now the MXA gang can love it without shame.

Q: WHAT IS THE GREATEST ATTRIBUTE OF THE 2011 SUZUKI RM-Z250?
 
A: Is it handling, suspension, ergonomics, brakes or power? There is no doubt that every other attribute plays second fiddle to the powerband. While excellent suspension and a chassis that handles well are important for a 250F, a powerful engine is critical. It’s interesting to note that in the 450 class there is a role reversal. The output of a 450 engine is important, but suspension and handling play equal roles. Why? All 450cc engines are fast enough for most mortals. The same cannot be said for 250cc four-strokes?which must be ridden hard, slammed through the gears and revved to the moon. Any soft spot in the powerband is magnified.

With that said, the powerband isn’t the greatest attribute of the 2011 Suzuki RM-Z250. Don’t get us wrong. We’re not selling the RM-Z250’s engine short (since Suzuki’s newest engine is the best RM-Z250 powerplant that we’ve ever tested); it’s just that the Suzuki chassis is a motocrosser’s dream. The RM-Z250 is the best-cornering 250 four-stroke on the market. It can navigate inside lines that the Kawasaki KX250F and Yamaha YZ250F can only dream of hitting. Once in a turn, the RM-Z250 arcs a smooth line (something that cannot be said for the Honda CRF250). Handling is precise, accurate and razor sharp. The RM-Z250 can make any skill level rider feel like a hero.
 
Q: DOES THE 2011 SUZUKI RM-Z250 PASS THE AMA SOUND TEST?

 
A: Stop yelling! We could hear a cat meow over the purring of the 90.3 dB that the RM-Z250 emits. This is a very quiet bike at 5000 rpm (where the AMA test is conducted). How did they do it? Suzuki decreased the core size in the muffler and worked on quieting miscellaneous engine noise. Amazingly, the 2011 RM-Z250 isn’t the quietest bike in 2011 (the Honda CRF250 comes in at a whisper-like 89.9 dB), but it’s darn close. As for the FIM two-meter-max test, the RM-Z250 blows a very-loud 118.1 dB?over the limit.

Q: WHAT IS THE RETAIL PRICE OF THE 2011 SUZUKI RM-Z250?

A: The 2011 Suzuki RM-Z250 isn’t the most expensive bike on the market, but it’s not the cheapest, either. The Yamaha YZ250F wins this category at $7150. The Honda CRF250 comes in second at $7199. The RM-Z250 and Kawasaki KX250F are tied for third at $7299 respectively, and the KTM 250SXF is the most expensive at $7699.


Agility: When the MXA test crew gathers around the campfire to talk about bikes, the handling of the Suzuki RM-Z250 is spoken of with reverence.

Q: WHAT ARE OUR BEST FORK SETTINGS?
 
A: We’re happy to report that the RM-Z250 is properly sprung. It should be noted that “properly sprung” and “RM-Z250″ have never appeared in the same sentence before. After years of outfitting the Showa units for featherweights, Suzuki finally realized that stiffer springs are needed for the vast majority of motocross racers. Racers over 170 pounds or faster than Intermediate speed should seriously consider jumping up a fork spring rate and lowering the oil height in 5cc increments until any harshness is gone, but for the vast majority of 250 class racers, the spring rates are ballpark.

For hardcore racing, these are MXA‘s recommended 2011 Suzuki RM-Z250 fork settings (when changed, stock settings are in parentheses):
   Spring rate:
0.47 kg/mm
   Oil quantity:
377cc
   Compression:
6 clicks out (10 clicks out)
   Rebound:
12 clicks out (11 clicks out)
   Fork leg height:
Flush with top clamp
   Notes:
The RM-Z250 is very sensitive to fork leg height. We found that running the forks flush with the top triple clamp balanced the suspension and fixed the minor headshake that we encountered through fast and rough sections.

Q: WHAT IS OUR BEST SHOCK SETTING?

A: For hardcore racing, these are MXA‘s recommended 2011 Suzuki RM-Z250 shock settings (when changed, stock settings are in parentheses):
   Spring rate:
5.7 kg/mm
   Race sag:
102mm
   Hi-compression:
2 turns out
   Lo-compression:
11 clicks out (12 clicks out)
   Rebound:
11 clicks out (14 clicks out)
   Notes:
The shock takes about an hour to break in. Continue to check the sag until the shock is completely broken in.

Q: WHAT DID WE DO TO IMPROVE THE 2011 SUZUKI RM-Z250?

A: The 2011 Suzuki RM-Z250 isn’t fault-free. The MXA wrecking crew recommends making these three changes in order to improve it:

(1) Clutch. The RM-Z250 has been perennially plagued with a buttery soft clutch that doesn’t last. The MXA wrecking crew was religious about keeping fresh oil in the transmission, constantly checking the clutch cable free play, and installing stiffer aftermarket clutch springs. We ran Pro Circuit springs (www.procircuit.com). The spring kit will set you back $69.95, but the payoff is worth it.

(2) Steering stem. An easy and free solution to the RM-Z250’s minor headshake woes is to tighten the steering stem nut. By no means do we recommend tightening the nut to the point where the handlebars barely turn, but taking excess slack out of the front end helps. Of course, a savvy rider will raise or lower the fork height to finesse the bike’s overall handling.

(3) Exhaust system.
The RM-Z250 is very quiet (and no matter what anyone tells you, when you make a bike quiet by reducing the core size, it loses throttle response). Suzuki managed to keep the same size end cap from the 2010 muffler (in order to save money), but decreased the size of the muffler core with a mod that is pure backyard engineering in its simplicity. Instead of making a new core size, which would require a new end cap, they slip-fit a section of smaller core into the old core to bring the size down. Going to an aftermarket exhaust system will allow the engine to perform the way that it’s supposed to?and still meet the AMA sound limits.

Q: WHAT DO WE HATE?

A: The hate list:

(1) Clutch. Burning through an RM-Z250 clutch in a couple of motos is not unheard of. The clutch plates are as weak as putty and are very prone to slipping.

(2) Shifting. It takes a few hours for the transmission to wear in, leading to more precise shifting. We never suffered any issues with shifting under a heavy load, only in finding neutral (which isn’t always such a bad thing).

(3) Throttle tube. You can forget about replacing the throttle side grip once it wears out, because Suzuki thermo-welds the grip to the throttle tube. You would have to turn the throttle tube down in a lathe to get the residual rubber off the plastic. It is much simpler to buy a replacement throttle tube.

(4) Bolts.
We get a fleeting sensation of dread every time our eyes come across the puny 8mm bolt heads on the RM-Z250 seat bolts. Suzuki’s overall bolt quality is very suspect.

(5) Tires.
If there were ever a Dr. Jekyll and Mr. Hyde pairing of tires, it would be the Dunlop D756 rear tire mated with the D742FA front. The 756 is wonderful, while the 742FA is a nightmare.

Q: WHAT DO WE LIKE?

A: The like list:
     

(1) Handling.
The RM-Z250 is the best cornering bike in the class. Whether that makes it the best overall handling bike depends on what your priorities are. If you want a bike that turns like it’s on a monorail, this is it. However, in straight-line rough situations, it is very busy.

(2) Suspension.
The Showa suspension isn’t perfect right out of the crate, but at least Suzuki spec’d the proper spring rates for a larger cross-section of motocross racers.

(3) Engine. The 2011 RM-Z250 engine may not be the best engine in the class, but it is worlds better than it was a few years ago. We commend Suzuki for finally building an engine that pumps out the ponies (and, best of all, delivers more top-end power).

(4) Brakes. Suzuki doesn’t have the best brakes in the business (that accolade goes to KTM), but their binders are still very good. The brakes have proper modulation and good power.

(5) Hot start. We have broken Suzuki’s thumb-style plastic hot start lever many times in the past, but not in 2011. We like that the hot start is located on the right side of the handlebars. It’s easy to use.

Q: WHAT DO WE REALLY THINK?

A: My, how the tables have turned! Last year, Suzuki barely produced any motocross bikes (and the ones they did release came so late in the season that no serious racer could wait for them). Rumors spread that Suzuki might pull out of the motocross market because of the poor economy. Thank goodness those rumors weren’t true, because the 2011 Suzuki RM-Z250 is a diamond in the rough. We love the updated powerband, real-world suspension settings and sharp-handling chassis. Suzuki improved their stock by releasing the 2011 RM-Z250. Yes, it’s that good.

facebooktwittergoogle_plusredditmailfacebooktwittergoogle_plusredditmail

Comments are closed.