GP’s Classic Steel #63: 2005 Suzuki RM250

For this week’s GP’s Classic Steel we are going to take a look back at the last 250 two-stroke to win an AMA Supercross Championship, the 2005 Suzuki RM250.

For this week’s GP’s Classic Steel we are going to take a look back at the last 250 two-stroke to win an AMA Supercross Championship, the 2005 Suzuki RM250.

If you look up the word “two-stroke” in a dictionary, this is the machine you should see. The 2005 RM250 snapped to attention at the slightest touch of the throttle and ripped through the powerband at warp speed. It was the exact antithesis of the new wave of thumpers taking over the sport.

These days, the roar and rumble of four-strokes has replaced the bark and brapp of the two-strokes at most tracks across our nation. Through a combination of wrong-thinking rule making and manufacturer neglect, the once ubiquitous two-smoker has been relegated to a motocross novelty act. Of course, it wasn’t always this way. For nearly forty years, the lightweight two-stroke single was the absolute state-of-the-art in off-road motorcycling. It was simple, reliable, lightweight and most importantly, produced more power per cubic centimeter than any other design available. Put simply, the two-stroke single was made for a sport like motocross.

The King of zing. After decades of playing second fiddle in the power sweepstakes, Suzuki finally hit the sweet spot in 2005. The 249cc mill barked from the first twist of the throttle and kept on pulling until the cows came home. It was quicker revving and less smooth than the electric Yamaha, but just as effective on the track.

Unfortunately, just as the two-stroke was reaching the pinnacle of its performance, several forces conspired to push it to the back-burner. In the mid-nineties, there was a great deal of handwringing going on in the off-road community over the EPA and predictions of a ban on two-strokes. Every year, brought with it more doom and gloom predictions of how the Fed’s were going to kill the sport we love.  While the dreaded EPA two-stroke crack-down never materialized (at least not yet), the runaway success of Yamaha’s YZ400F did. The original five-valved wonder got people thinking thumper, and by the time the 2005 RM250 hit the showroom, the writing was on the wall.

Nothing else quite handles like a Suzuki. They feel lighter, turn sharper and fly farther than the other brand’s machines.

In spite of being out of fashion, the early 2000’s were a great time to be a 250 two-stroke aficionado. By 2005, all the manufacturers were building very good 250’s. Honda was on the third generation of its aluminum frame and had finally figured out how to make it handle (although its case-reed motor was less popular than earlier efforts). Kawasaki’s KX250 had an all-new motor with a major infusion of power and Yamaha had the do-it-all power plant of the class and an all-new aluminum chassis. While the RM250’s design may have actually been the oldest of the bunch in 2005, a campaign of careful refinement had honed it into a finely crafted motocross weapon. The tide may have been turning against the two-stroke in 2005, but the good old 250 smoker was not going down without a fight.

In addition to its wide and explosive powerband, the RM was blessed with the slickest and smoothest shifting tranny in the class. In the motor sweepstakes, its only weakness was its wimpy clutch, which became grabby and difficult to modulate with abuse.

The design of the 2005 RM250 actually dated back to 2001, when Suzuki had unveiled its latest and greatest (and, as it turned out, last) deuce-and-a-half MX machine. The ’01 RM was a substantial upgrade from the controversial ’96-‘00 model and was well-liked by testers. It offered a very “Suzuki” experience, which meant razor sharp turning and a potent, quick revving and hard hitting mill. By ’05, Suzuki had refined that RM “flavor” down to a science, while adding in a little Yamaha YZ for good measure.

In late 2004, Suzuki pulled the coup of the century by snagging Ricky Carmichael away from Honda. Amazingly, after delivering five titles in three years (the only one he did not win, was the one he pulled out of due to injury), Honda declined to re-sign the GOAT and Suzuki was more than happy to grab up the winningest rider in AMA history. In 2005, RC would reward Suzuki with its first Supercross title in 24 years.

Starting in 2000, Yamaha had dominated the 250 rankings with a near perfect blend of easy-to-ride horsepower and solid chassis manners. Team Blue built on the solid work done by Honda and Kawasaki the decade before, to create perhaps the ultimate 250 two-stroke power plant. It had the solid low and mid of the KX, combined with the top end pull of the Honda. It was a true jack-of-all-trades, which hooked up on the greasiest dirt and ripped out of the deepest loam.  In the early 2000’s, other brands could beat out the Yamaha at certain points on the curve, but nothing could touch its amazing spread of hooked-up horsepower.

During this period of blue domination, Suzuki was carving out its own particular niche as the King of zing. Unlike the YZ, which ran (dare I say it) almost like a four-stroke, the RM was all about hard hit and quick turnover. It was snappy, quick and explosive. This power was perfect for Supercross and while not as easy to use as the YZ, very competitive.  Where the RM fell short of the class leading YZ, was in the breadth of its power. After its explosive low to mid hit, the RM demanded another shift, while the YZ could be stretched out to the next turn. If Suzuki were going to claw away the title of class champ, they would need to reinvent their one-dimensional power plant.

The 47mm “Twin-Chamber” (so named for its sealed internal oil cartridge which prevented air contamination in the damping fluid) Showa forks on the RM did a masterful job of taming the track in ‘05. They were stiff enough for anything short of Supercross, while plush enough to take the bite out of choppy outdoor style hits. These were excellent forks.

For 2005, Hamamatsu went after the 250-class benchmark with a series of changes designed to broaden the RM’s power curve. In order to squeeze more top end out of the RM’s 249cc mill, Suzuki’s engineers raised the exhaust ports and widened the scavenging ports. They also reshaped the squish band of the combustion chamber to slightly lower the compression (also, in hopes of achieving more revs). Lastly, Suzuki added weight to the RM’s crank to smooth out the hit and help the RM carry its power further into the upper ranges (a trick the Factory RM’s had used for years).

While not up to the standards of a modern KTM, the brakes on the RM were considered excellent in their day. Strong, trouble free and easy to modulate, these binders were the best brakes available from Japan in ’05.

The result of all this massaging was a longer and stronger flow of power for 2005. The RM still barked out a very responsive flow of torque off idle, but combined it with a strong top-end hook. Even with the added crank inertia, the RM was still snappier and quicker revving than the YZ. Where the YZ was silky smooth and hooked up, the RM was “right now” abrupt and ultra-responsive. In terms of outright power, it was almost a dead heat between these two two-stroke titans. Neither the lethargic CR nor the fast (but top-end-focused) KX could match these two’s combination of outright power and usability. In the end, it came down to personal preference as to who had the top 250 power plant of ’05. Smooth or snappy- you make the choice.

This is one damn fine looking motorcycle. In my opinion, every Factory RM of this body style was a looker. From the Sobe bikes to the Makita years, the works RM’s were on point in the early 2000’s.

In the suspension department, the RM was dialed in 2005. Both its Showa Shock and Showa forks were at, or near the top of the class. With Yamaha’s renowned Kayaba SSS components still a year away, no one else was able to top the yellow machines combination of excellent spring rates and plush performance. The 47mm Twin-Chamber Showa forks mounted to the RM were stiff enough for anyone short of Ricky Carmichael, while retaining excellent bump absorption. They gobbled up bumps and craved big hits. These were excellent forks and far and away the best set up boingers of 2005.

The shock on the ’05 RM was just as sweet as the forks, and head and shoulders at the top of the class. Spring rates were spot on for motocross use and in the ballpark for anyone short of an AMA pro. The Showa unit tracked straight in the rough, floated though the whoops and craved the big hit. It never kicked, hopped and took the rider by surprise. This was one very well sorted out rear end.

The return of the Full-Floater. While it may not have shared the name with its exotic forebear, the ‘05 RM certainly shared its performance.  Equally at home pounding whoops, swallowing stutter bumps, or conquering doubles, the RM’s Showa shock was the best rear end in motocross.

As with the rest of the bike, by 2005, Suzuki had mellowed out some of the RM’s more “aggressive” handling peccadillos. For the past thirty years, the one trait that has defined Suzuki handling has been its razor sharp turning. This affection for the inside line has often come at the expense of stability, however, as RM’s tended to dance and wander at speed. This hyperactive personality required a good deal of concentration, as well as a fair amount of courage, to corral on fast and bumpy circuits.

2005 was an epic year on the track for Suzuki (with epic battles to match between RC, James Stewart and Chad Reed). After decades of trying to recapture lost glory, RC and DeCoster would bring home the 250 Supercross, 250 Outdoor National, MXoN and US Open SX titles.

In an effort to tame the wild beast, Suzuki changed the head angle from 24.5mm to 22.5mm on the new RM. This slight change (combined with several other refinements from 2001-2004) had the ‘05 RM250 dialed into an absolute Supercross weapon. No line was too tight, no turn too tricky, for the yellow Ginsu of motocross. It was still slightly loose and schizophrenic at speed, but less so than previous offerings. Its super quick turning and instantaneous power made the RM the perfect bike for Supercross style tracks. It could snap out of any corner and nail that tricky double with the greatest of ease. It was quick, light feeling and ultra-responsive, but also busy, nervous and prone to headshake at times. Depending on the track, this could be either a blessing or a curse, but it was never boring.

While the all-new RM-Z450 four-stroke got a premium Renthal “Fat Bar” for 2005, the lowly and unloved two-strokes had to make do with this generic Wal-Mart brand alloy knock off.  While it may have lacked the “bling” factor of the Renthal, it was still a huge improvement from the butter soft steel bars it replaced.

In the details department, the ’05 RM250 finally left the eighties in the rear view mirror with the addition of an aluminum handlebar for the first time. The fact that it was a nondescript alloy unit instead of the fancy Renthal the RM-Z450 got was probably telling, but at least it was an improvement over the butter bars used previous to ’04. Other parts on the good list included strong and progressive brakes, titanium footpegs and silky smooth shifting. On the bad list, were its eject-o-matic tank decals, a weak clutch and generally accelerated wear and tear.

It is fitting that perhaps the most “two-stroke” 250 ever made would be the last one to ever win a major US SX/MX title. The ’05 RM embodied everything that made two-strokes fun and distilled it down to a perfect combination of fun and fury. It was the quickest of the quick and the sharpest of the sharp. It made riding fun and winning easy; what more could you ask from a motocross machine?

In 2005 Suzuki hit one out of the park with the RM250. It barked, it braappped, it shredded and gave you back two bucks in change. It was the very definition of a two-stroke race bike and the antithesis of every booming thumper thundering around America’s racetracks.  While it may not have been as fast as its 450 competition, it was lighter, easier to maintain and cheaper to own. Unfortunately, this was not enough to save the RM250 from the hangman’s noose, but it was a great last hurrah for one of the all-time classic motocross icons.

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