For this edition of Classic Steel, we are going to take a look back at Suzuki’s all-new RM250 for 1986.
All-new from the ground up, the 1986 RM250 looked to bring back the glory days of Suzuki’s early ‘80s 250 success. Photo Credit: Suzuki
The late seventies and early eighties were a great time to be riding RMs in the 250 division. Starting with the introduction of the first RM250 in 1976, the yellow machines earned a well-deserved reputation for being some of the best all-around machines available in the 250 division. The middleweight RMs were not always the best in any one category, but they excelled on the track by being well-suspended, good-handling, and easy to ride.
From 1981 through 1985, Suzuki’s Full Floater was the best-performing rear suspension in motocross. In 1986, legal troubles, cost cutting, and a move toward simplicity would result in Suzuki shelving the original Full Floater in favor of a more Honda-like bottom link design. Photo Credit: Suzuki
In 1981, the RM250’s stock took a major leap forward with the introduction of a ground-breaking all-new rear suspension system. Coined the Full Floater, the RM’s new suspension did away with the laid-down dual shocks in use since 1976 in favor of a far more complicated single shock design. The heart of the Full Floater was its unique system of linkages and pull rods that isolated the shock from the chassis at both the top and bottom mounting points. This allowed the shock to “float” independently from the rest of the machine and provide superior tracking in the rough. This revolutionary system proved to be an immediate success and riders of all skill levels praised the Full Floater for its incredible ability to smooth out the track.
The redesigned Full Floater for 1986 did away with the pull rods and rocker arms of the original design in favor of a simpler bottom link configuration. The new layout used an eccentric cam to vary the linkage curve and offered the advantages of lower weight, better mass centralization, and reduced complexity. Photo Credit: Suzuki
In 1982, Suzuki added a rocket motor to the mix and the RM250 proved to be nearly unbeatable. The RM’s new liquid-cooled mill hit hard, revved fast, and pulled to the moon. Its combination of mega power, light weight, sharp handling, and flawless rear suspension dominated the charts with the Suzuki once again claiming the crown of best 250 in the land.
In many people’s minds the biggest development on the Suzuki front for 1986 was the hiring of the sport’s winningest rider Bob Hannah to the race team. While Hannah’s winning days were largely behind him, his expertise as a development rider would prove invaluable in getting Suzuki’s flagging production machines back to a competitive state in the late 80s. Photo Credit: MOTOcross
In 1983, the competition caught up with Suzuki fumbling its horsepower advantage. The new RM was lighter, stabler, and even better suspended, but changes aimed at broadening its powerband ended up neutering its blistering performance. The new bike was easier to ride and still competitive, but many found its new mellower personality a disappointment.
The redesign of the Full Floater meant Suzuki could reduce the parts needed in the RM’s chassis construction by a remarkable 50%. This simplified production and allowed Suzuki to make the frame slimmer and lighter. Photo Credit: Suzuki
The 1984 season brought with it another all-new RM250, this time with a blue frame and updated works styling. The redesigned machine featured an all-new chassis, beefed-up suspension, and a refined version of the ’83 RM mill. The updated motor gained a larger airbox, new porting, and a revised exhaust in search of the 1982’s lost horsepower. While this yielded a 1.6 horsepower gain on the dyno, it remained far short of the output delivered by its top competitors in 1984. All three Japanese 250s outmuscled the RM and it remained a great-suspended bike in need of more power.
An all-new motor for 1986 added a “power valve” to the RM250 for the first time. Very similar in concept to Honda Automatic Torque Amplification Chamber (ATAC), the new Suzuki Automatic Exhaust Control (AEC) varied the geometry of the exhaust system through the use of a sub-chamber built into the exhaust port. In theory, this allowed the RM’s engineers to mimic the performance of a “torque” pipe and a “rev” pipe with one exhaust. Photo Credit: Suzuki
A front disc brake and a coat of silver paint for the motor were the biggest RM250 headlines for 1985. Another retread of the mellow ’83 motor yielded predictable results while the innovative but complicated Full Floater rear suspension continued to deliver the best ride in the class. With good handling, excellent suspension, and an easy-to-ride motor, the RM250 made an excellent junior-level racer but not much of a pro-level weapon.
One feature that set the AEC apart from its nearly identical Honda counterpart was this external adjuster that allowed the spring tension of the power valve’s engagement to be fine-tuned. Photo Credit: Motocross Action
In 1986, Suzuki knew that they were going to need to step up their game to have any chance of reclaiming their former glory. With the Production Rule taking effect in America in 1986, it would be more important than ever to provide their race team with a competitive machine right out of the crate. In addition to the new regulations being implemented in the US, legal battles would also force Suzuki to move away from its original Full Floater design.
One major change to the sport in 1986 was the adoption of the Production Rule by the AMA. This meant the race teams could no longer field exotic one-off machines that bore no resemblance to what consumers could find on the showroom floor. While this was a win for Average Joes, it made life harder for riders like George Holland who were forced to campaign machines that were a step behind their competitors. Photo Credit: Dirt Bike
In 1974, a young inventor by the name of Donald Richardson devised a rear suspension system for his motocross machine that replaced the dual shocks common at the time with a single damper and bell-crank rising-rate linkage. Richardson patented the design and in 1978 entered into a contract with Suzuki to refine and develop his suspension system. In the agreement, Richardson was required to disclose all technical information about the theory and implementation of his rising-rate design.
While the original Full Floater is universally praised for its performance, the story behind its development is more controversial. Much of the DNA that went into its initial construction was the work of a young engineer by the name of Don Richardson. Initially, Suzuki partnered with Richardson, but the Japanese brand ended their relationship before the Full Floater made it to production. The result of this inequitable parting was a lawsuit aimed at Suzuki and others whom Richardson felt had taken his ideas and then sought to cut him out of the profits. Eventually, Richardson would win his suit and Suzuki would be forced to pay him millions in damages. If you would like to learn more, Richardson has the above book available on Amazon detailing his side of the events that took place.
In December of 1979, Suzuki declined to exercise the option on his contract and ended ties with Richardson. Two years later, the Full Floater when into production using several of Richardson’s innovations. In 1982, Richardson filed a patent infringement action against Suzuki claiming breach of contract, breach of good faith and fair dealing, and misappropriation of trade secrets. What followed was a protracted exchange of suits and countersuits that would end with Richardson being awarded 50 cents for every Suzuki sold with the original Full Floater in the US and $12 for every Full Floater equipped Suzuki worldwide. Depending on sales figures, this equated to an award of somewhere between 6 and 18 million dollars to Richardson.
An all-new pilot compartment for 1986 offered a slimmer and trimmer layout than before. While an improvement over the old RM, many riders still felt the Suzuki’s ergonomics and feel were a step behind what was available from the competition. Photo Credit: Suzuki
While this legal entanglement was ignored by the enthusiast press, there can be little doubt that it played some part in the demise of the original Full Floater design. Due to its large size, high center of gravity, and complicated construction, the original Full Floater would most likely have been displaced eventually, but in 1985, it was still the best-performing rear suspension in motocross.
Visually, the bright blue motor helped the RM stand out from the crowd, but the rest of its athletics were starting to be a bit stale by 1986. Photo Credit: Suzuki
With the future of the original Full Floater in doubt, it was decided that the all-new 1986 RMs would feature a complete redesign of the iconic rear suspension system. By this point in the mid-eighties, most manufacturers had concluded that Honda’s original bottom-link design offered the best combination of packaging and performance. By placing the linkage below the shock, the heaviest parts of the mechanism were kept low on the chassis and the linkage mechanism no longer interfered with the placement of the air box. In 1986, Suzuki moved to a bottom-link design but chose to go with a unique implementation.
In addition to the add-on of the AEC, Suzuki’s engineers decided to go with a longer stroke and smaller carburetor for 1986. This was done to beef up the RM’s low-to-midrange torque and hopefully bring it up to snuff with powerhouses like Yamaha’s YZ250. Photo Credit: Suzuki
Instead of a traditional set of linkage arms connecting the shock to the swingarm, Suzuki chose to use an eccentric cam to vary the leverage delivered to its KYB shock. This new system was lighter, more compact, and considerably less complicated than the original Full Floater design. This allowed Suzuki to reduce manufacturing costs, slim the midsection of the machine, and lower the center of gravity of its RMs. Aside from the unique linkage, the rest of the second-generation Full Floater was a thoroughly conventional design with a large single Kayaba shock delivering 12.4 inches of travel with 17 adjustments for compression and 21 settings for rebound available. For 1986, the KYB damper received a larger remote reservoir to fight fading and revamped valving designed to work with the redesigned linkage.
In addition to old dogs like Bob Hannah, Suzuki had quite a stable of young lions under their tent in 1986. Here George Holland pilots his factory Suzuki to 10th place in San Diego in 1986. Photo Credit: Naoyuki Shibata
Up front, the 1986 RM250 featured a set of 43mm conventional Kayaba forks delivering 11.8 inches of travel. The forks were new for 1986 with a redesigned valving system incorporating a blow-off valve to improve compliance on hard hits. A new progressive-rate spring was added and the amount of selectable settings for compression damping was reduced from 17 to 8 for 1986. While updated, the fork’s damping system remained an old-school damper-rod design that lacked the sophisticated works-style cartridge damping system found on the Honda CR250R. Only Honda had this innovation in 1986 and the rest of its competitors suffered for its absence.
The ’86 RM250 offered a solid burst in the middle but not a lot on the margins. To keep it percolating you had to be quick on the trigger and fast on the shifter. Photo Credit: Motocross Action
Paired with the all-new suspension was a completely redesigned frame that was narrower, lighter, and stronger for 1986. Constructed of tough chromoly steel, the new chassis reduced the components used in its construction by 50 percent over 1985. The redesigned frame was more compact and narrower through the midsection by half an inch via the use of oval tubing where the rider gripped the machine. The new chassis was also shorter overall with the RM dropping an inch of wheelbase for 1986. While the overall look of the RM’s bodywork was very familiar only the front and rear fenders remained a carryover from 1985. An all-new tank offered a slightly slimmer profile and an all-new saddle carried farther up the tank. Repositioned radiators were mounted lower in the frame and new shrouds were bolted on to work with the revamped tank and updated layout. The redesigned side plates remained similar in appearance to 1985 but featured a revised shape to accommodate the new frame and rear suspension. Bold new graphics and a bright coat of blue paint for the motor finished off the significant visual changes for 1986.
All-new forks for 1986 offered progressive springs and fewer adjustments. As delivered from the factory, these 43mm KYB conventional units lacked plushness and delivered a jarring ride that placed them firmly at the back of the fork pack in 1986. Photo Credit: Suzuki
In addition to the all-new chassis and suspension, Suzuki rolled out the first major redesign to its liquid-cooled 250 power plant since its introduction in 1982. The revamped motor was all-new from the ground up and featured Suzuki’s first implementation of a “power valve” to broaden performance. Suzuki’s name for its new system was “Automatic Exhaust Control” (AEC) and it consisted of a valve and sub-chamber built into the exhaust port that allowed the engineers to vary the volume and flow characteristics of the exhaust gases as they exited the combustion chamber. At low RPM the valve was open to the sub-chamber, mimicking the characteristic of a “torque” pipe to boost low-end performance. As the RPM increased, a centrifugal-ball governor rotated the drum valve to close off the sub-chamber and allow an unencumbered flow of exhaust to the expansion chamber. By varying the geometry of the exhaust system, the AEC allowed Suzuki’s engineers to give the RM the power characteristics of two different exhaust systems in one. Unlike Honda’s very similar ATAC (Automatic Torque Amplification Chamber), the Suzuki design did allow for fine-tuning of the mechanism through the use of an externally-adjustable preload spring.
In 1986 there were two solid contenders, one back marker, and one all-star in the 250 class. While the RM, YZ, and KX all had their boosters, the CR250R’s combination of motor, handling, and suspension performance delivered a knock-out blow that left the competition reeling. Photo Credit: Motocross Action
Like the chassis, the motor was narrower in 1986 with Suzuki reworking the transmission and clutch mechanism to reduce the width of the motor by seven percent. The redesigned transmission featured new ratios and slightly smaller gear sets while the clutch moved to a rack-and-pinion engagement to improve action and slim down the mechanism. Both the connecting rod and coolant system were lighter for 1986 with the water pump adopting a direct drive from the crankshaft and deleting two hoses from the ’85 motor. To further boost low-end torque, Suzuki’s engineers increased the motor’s stroke for ‘86 and reduced the size of the carburetor from 38mm to 36mm. The mixer retained Mikuni’s VM flat-slide design, but the smaller size was said to improve low-to-midrange throttle response. Internally, the new cylinder featured revised porting and enlarged coolant passages for increased reliability. To gain back some of the top-end performance sacrificed by the smaller carburetor, Suzuki enlarged the airbox and redesigned the exhaust system. The new pipe was tuned to take advantage of the AEC and reshaped to tuck in better for improved ergonomics. Paired with the new pipe was a redesigned oval alloy silencer that Suzuki claimed was quieter for 1986.
After five years of suspension domination Suzuki took a major step backward in 1986. The redesigned Full Floater was plagued by stiction and delivered a harsh ride on small bumps and chatter. Big hits were no issue, but the shock’s low-speed performance relegated it to last place in the ’86 suspension standings. Photo Credit: Suzuki
Bob Hannah’s race schedule in 1986 was limited to a few choice events held at tracks he favored. His win at the Unadilla 250 USGP in July proved that the old man of motocross still had what it took when the conditions favored him. Photo Credit: Dirt Bike
On the track, the all-new RM250 turned out to be largely a disappointment. The all-new motor failed to deliver on the promises of the AEC and produced a lackluster powerband that was both slow and hard to ride. Low-end torque was all but nonexistent despite the addition of the smaller carb, longer stroke, and power valve exhaust. Out of turns, the RM was sluggish to respond, and any sort of deep soil demanded a fan or two of the clutch to get the Suzuki going. The midrange power was slightly improved but the RM continued to be outmuscled in the middle by the CR and KX. Top-end pull performance was average at best with the Suzuki pulling farther than the tractor-like Kawasaki but far less enthusiastically than the Honda and Yamaha. At its peak, it gave up over two horsepower to the CR and YZ and what thrust it did have was delivered over a very short burst in the middle. Short shifting or over-revving the motor resulted in a significant drop in power and it was critical to keep the bright blue mill in the sweet spot of its narrow powerband to have any shot at keeping its rivals in sight. In stock condition, it was too slow for fast guys and too demanding for many novices. With major motor work, the RM’s mill could be competitive, but in the stock condition, it was by far the most disappointing power plant of 1986.
The RM’s greatest asset in 1986 was its handling and the bike could be trusted to hold its line in the turns and at speed. Photo Credit: Dirt Bike
On the suspension front, the RM was once again a serious disappointment. As this was previously the bike’s biggest advantage, this setback was doubly disappointing. The new non-floating Full Floater lacked all of the plushness its predecessor was famous for and delivered a harsh ride that was panned by all. The small bumps and chatter that the 1985 RM gobbled were transmitted directly to the backside of the rider on the ’86. Both the damping and spring rates were super stiff, and the rear of the machine only seemed to be happy when coming down from the stratosphere on big hits. Some of this lack of compliance was traced to the new linkage which suffered from abnormally high drag. The eccentric cam design demanded constant servicing and if you neglected it, the mechanism became a major hindrance to the shock’s action. If you were Bob Hannah, the new Full Floater probably worked, but for the rest of us mortals, the new-look rear end delivered back-of-the-pack performance.
Despite its many upgrades the new RM’s 246cc mill delivered disappointing performance. Low-end power and top-end pull were sorely lacking with the bike delivering what power it did have over a short burst in the middle. Photo Credit: Suzuki
Up front, the news was not any better with the revamped forks delivering a similarly harsh and unforgiving ride. This time, soft springs and overly aggressive damping were to blame for the Kayaba fork’s disappointing performance. In stock condition, they hung down in the travel and hammered into a wall of damping force on small and medium-sized bumps. This spike in the travel was transmitted directly to the rider’s wrists and the RM was noted for its ability to pump up its rider’s arms in short order. The new blow-off valve incorporated into the ’86 forks did not seem to activate on anything less than a two-story drop off and the bike was only happy when slamming into cliff faces or landing from serious sky shots. With stiffer springs and some fork oil fiddling, they could at least become livable, but even with these mods, they were never going to be as smooth and plush as the Honda’s amazing Showa cartridge units.
With its narrow power and harsh suspension the RM required a “go for broke” approach to keep up with its rivals. Photo Credit: Dirt Rider
On the handling front, the RM250 was far more successful in 1986. The new shorter chassis turned very well, and the bike’s front end could be trusted to hold its line in most conditions. The lowered center of gravity for 1986 was noticeable on the track, but the bike still felt more top-heavy than most of its competitors. This did not ruin the RM’s handling but some riders did feel it did not “flow” through the turns as gracefully as machines like the Honda CR250R. High speed stability was much better than the CR, however, and more than a few riders felt it offered the best combination of turning prowess and fifth-gear confidence in the class. The harsh stock suspension seemed to work better the faster you went and the RM rarely shook its head and generally went where it was pointed. The bike’s jumping manners were praised as well, and the RM was more than happy to conquer any gap the pilot was willing to attempt.
Erik Kehoe was another young star on the Suzuki squad in 1986. While Kehoe was solid in the 250 class, his best results were always in the 125 division. Photo Credit: Kinney Jones
On the detailing front, Suzuki needed a bit more fine-tuning in 1986. The bars, grips, and levers were all a step behind the best in the class, and more than a few curse words were uttered while trying to remove the RM’s infuriating vulcanized throttle grip. The RM’s myriad of bolt sizes and the inordinate amount of washers also made it more time-consuming to work on than many of its competitors. The brakes were mediocre at best with the front disc and rear drum offering barely adequate performance. The rubber hose used for the front disc delivered a mushy feel at the lever and maximum power was well below what was offered by the Honda and Kawasaki. Adding a braided steel line helped with the mushy feel, but even with that upgrade, it was not as strong as the binders found on the competition. The new clutch proved durable, but the engagement was not particularly smooth and the pull at the lever was too firm for many. The transmission shifted well, but some RMs (including the MXA test unit) suffered expensive transmission failures in 1986. The new Full Floater design had a lot fewer moving parts to service, but the eccentric cam linkage proved to be in constant need of attention. If you neglected to lubricate the cam regularly, then the drag from the linkage had a noticeable effect on the shock’s performance. Constant servicing was a must if you hoped to avoid huge amounts of stiction from the rear end.
The new eccentric cam Full Floater linkage proved prone to inordinate amounts of stiction and would only last one year on the full-size RMs. Photo Credit: Motocross Action
While the stock RM250 was no rocket, it was capable of impressive speed with a talented rider like Bob Hannah at the controls. Photo Credit: MOTOcross
In terms of appearance, the RM was a bit of a mixed bag in 1986. Most riders dug the new blue motor and overall color scheme of the machine, but the bodywork was starting to show its age. Some riders appreciated the unique “Suzuki” look, but there was no denying that the RM was not as well finished as machines like the ‘86 YZ and CR. Big gaps in the bodywork and oddball shapes for the plastic made the bike’s appearance a love-it-or-hate-it proposition to most. While this certainly set the RM apart, many riders at the time felt that it did the bike no favors in the showroom.
The stock grips on the RM were real palm-chewers and removing them was a real pain in the kidney belt due to Suzuki’s decision to vulcanize the grip directly to the throttle. Photo Credit: Suzuki
Aside from its appearance, the new bodywork was largely an improvement for 1986. The new layout was slimmer and the longer seat made it easier to slide forward in turns. Shorter riders also appreciated the easy reach to the ground the RM’s low seat height afforded. While this was a boon for those below 5’9”, taller riders found the Suzuki’s layout rather cramped. The stock seat foam was also given a thumbs down for sacking out quickly and allowing every jolt from the harsh shock to make it right to the rider’s backside. Many riders also felt that the RM’s “sit in” ergonomics felt rather old-fashioned compared to the flatter layout seen on sleek new machines like the redesigned YZ.
Today, these footpegs look more like toothpicks but in 1986 these were what you would find on every stock machine. It was not until 1990 that Kawasaki would kick off the movement toward wider pegs. Photo Credit Suzuki
Overall, the 1986 RM250 proved to be a massive disappointment for Suzuki fans. The enthusiasm for an all-new machine quickly turned to bitter resignation as the machine’s performance deficiencies became readily apparent. After years of dominating the suspension category, the RM plummeted to the bottom of the standings in 1986. The new Full Floater was harsh in action and the forks were wrist-busting. The new power-valved motor failed to deliver on its promised torque and nearly everyone thought the older and simpler ’85 motor was probably better. In the end, it was only the RM’s handling that failed to disappoint. Slow, cobby-looking, and poorly suspended, the 1986 RM250 stands as the low point of Suzuki’s performance in the 1980s.
All-new and all blue, the RM250 took lots of chances in 1986 but not many of them paid off. Photo Credit: Suzuki
For your daily dose of moto goodness, you can follow me @tonyblazier on Instagram and Twitter.
