MXA RACE TEST: THE REAL TEST OF THE 2021 SUZUKI RM-Z450

THE GEAR: Jersey: Fly Racing Kinetic K121, Pants: Fly Racing Kinetic K121, Helmet: Fly Racing F2, Goggles: Fly Racing Zone Pro, Boots: Sidi Crossfire 3SR.

Q: FIRST AND FOREMOST, IS THE 2021 SUZUKI RM-Z450 BETTER THAN THE 2020 RM-Z450?

A: No. But just so you know, the current RM-Z450 package was first introduced in 2018, received a minor shock spring update in 2019 (from a 56 N/mm spring to a 54 N/mm spring) and was not updated, save for minor cosmetic changes, in 2020 and 2021. Unfortunately for Suzuki, American consumers are under the false impression that the RM-Z450 has not been updated in 20 years. What Suzuki has here is a “failure to communicate.” However, the 2022 Suzuki RM-Z450 will not be change—not even the graphics.

Q: WHAT FORCES ARE DRIVING SUZUKI TO ESCHEW UPDATES ON THE RM-Z450?

A:  What would Suzuki need to do to change its fortunes in the 450 class? 

(1) The first thing Suzuki would need to do is stop the “snowball effect?” Most important, Suzuki must sell a lot more RM-Z450s than they currently do. When a model doesn’t sell well, the corporate product planner orders fewer units for the next year. And when a bike doesn’t sell well year after year, partially because the buying public doesn’t embrace it and the production numbers don’t support spending R&D on it, it slips way down on the manufacturer’s “hot commodities” list.

(2) Stopping the snowball effect has traditionally required an all-new machine. Four years ago, Suzuki updated the RM-Z450 but focused on the things that the consumer didn’t care about and ignored the changes they actually wanted. In short, Suzuki made changes to the frame that hurt rather than helped and did nothing to the powerplant that was in dire need of updating. The paradox is that Suzuki has had more time to think about what it would do than almost any motocross bike manufacturer in history‚ and what they did wasn’t worth the wait.

(3) What Suzuki desperately needed to do was lose at least 10 pounds, add electric starting, get rid of the weird BFRC shock, design a totally new engine (not just because the current engine is the slowest in the class but because this powerplant has lost consumer confidence), build a clutch that maximizes power (instead of slip), and find engineers and test riders who prioritize balance over partial fixes.

(4) Suzuki’s engineers should have focused all of their attention on the RM-Z450 engine. After all, it has not seen a major upgrade in eight years. Why didn’t they? Because an all-new, finger-follower, 60-horsepower engine would require virtually every component to be redesigned, especially given that the engine is the most likely place to lose weight. An all-new, lightweight, high-horsepower, electric-start engine could cost as much as $10 million in casting, engineering and testing expenses.

(5) The RM-Z450 sales figures do not support, at least from a marketing point of view, spending that much R&D money on a bike that makes up a minuscule percentage of Suzuki’s bottom line. And given that Suzuki spent the greater part of the last decade watching its competition pull away with new technology, the task of keeping up with the Joneses (or in this case the Pierers) has become more difficult.

(6) It isn’t that Suzuki doesn’t have the engineers, know-how or capability to build a world-beating RM-Z450; it’s that Suzuki has back-burnered motocross bikes to pursue other interests.MXA test riders like the power profile of the RM-Z450, but it requires a different mindset to race against the stronger and higher-revving competition.

Q: HOW DOES THE 2021 SUZUKI RM-Z450 RUN ON THE TRACK?

A: Most MXA test riders like the 2021 Suzuki RM-Z450 powerband. For the average Novice, Vet or play rider, the existing RM-Z450’s power is located in the perfect spot on the rpm curve to get the job done; however, for more serious racers, the 2021 RM-Z450 gives up too much horsepower on top. If you are a wanna-be Pro or a high-rpm revver, you will not like the RM-Z450 powerband. The competition pumps out at least 58 horsepower in stock trim, while the RM-Z450’s 54.42 horsepower is way behind the curve. That missing 4 horsepower will be a liability on a long start, steep uphills, deep sand or a drag race from corner to corner.

Plus, you can’t rev the Suzuki RM-Z450 because it doesn’t want to be wrung out. At 11,000 rpm, the 2021 Suzuki RM-Z450 makes 7.69 horsepower less than the 2021 YZ450F. The RM-Z450’s 54.39 peak horsepower is at 8800 rpm. The RM-Z’s 8800 rpm is very low on the powerband when compared to the YZ450F’s 58.56 horsepower at 9700 rpm. After 8800 rpm, the Suzuki is dead in the water. The RM-Z450 makes power up to 8700 rpm, and it’s all downhill from there. It will rev to 11,000 rpm, but that last 2200 rpm is nothing but noise.

It is not our intention to make the 2021 Suzuki RM-Z450 engine appear to be a lost cause, because when short-shifted, kept in the meat of the powerband and used properly, it has a very usable, pleasant and effective 450cc powerband. It is brisk off the bottom and strongest from 7000 to 8700 rpm (where the acceleration is generated). 

A lightweight, electric-start, 58-horsepower engine will cost Suzuki about $10 million in R&D costs in the future.

Q: WHAT DID THE MXA TEST RIDERS LIKE ABOUT THE 2021 RM-Z450?

A: Living with the 2021 Suzuki RM-Z450 means you have to work with what it gives you, fix what is broken and spend your meager cash to get it where you want it. Here is what we liked.

Powerband. Every test rider loved the powerband because, in the middle of a long moto, when the bumps and jumps are working your body over, the clean bottom and nice midrange are rider friendly.  

Tuneability. The 2021 RM-Z comes with three plug-in maps: stock (black), aggressive (white) and mellow (grey). Most test riders preferred the stock plug-in for general racing.  What is new for 2021 is that Suzuki has joined the “Smart Phone Tuning Club” with its GET-developed MX-Tuner 2.0 app for Apple and Android phones. The app comes with four pre-programmed maps (aggressive, smooth, rich and lean), and you can make your own custom maps by changing the numbers in the 36 available boxes. You have to plug the MX-Tuner 2.0 connector into RM-Z’s data cable to upload your selected or custom maps into one of the three Suzuki couplers. But, you also have to connect a separate 12-volt battery into the RM-Z450’s battery connector to provide power (and you have to connect the battery any time you want to download a new map). This whole system is much harder to use than necessary.

Cornering. We wouldn’t go so far as to say that the 2021 RM-Z450 is the “best turning” bike anymore. Suzuki had a long run at the top of this category, but most of its competitors have caught up or surpassed Suzuki. In fact, the new chassis isn’t as good at cornering as the previous 2017 chassis.

Ergos. The bodywork is narrower. The bar bend is comfortable, and everything falls at hand easily. That may sound good, but the stinkbug chassis setup takes away from all of the good things, which is why fixing the chassis’ balance should be your first priority.

Price. The 2021 MXA 450 shootout-winning Husqvarna FC450 retails for $10,299. By comparison, the 2021 Suzuki RM-Z450 retails for $8499. That is an $1800 difference. Even the three next lowest priced 450s (Yamaha, GasGas and Kawasaki) are $900 over the RM-Z450’s MSRP. The 2021 Suzuki is a bargain.

Q: WHAT DID THE MXA TEST RIDERS HATE ABOUT THE 2021 RM-Z450?

A: MXA’s job is to evaluate each machine thoroughly enough to separate the wheat from the chaff. Here is a list of the RM-Z450’s chaff.

(1) Weight. At 241 pounds without fuel, the RM-Z450 is the heaviest bike on the track. 

(2) Starting. Not every bike made needs to be outfitted with electric starting, but if we had to pick one bike that needed it more than any other, it would be the Suzuki RM-Z450. Why? Because its kickstart lever is so high on the cases that short riders, riders with bad knees and weak riders can’t get a full kick.

(3) Clutch. None of the Japanese clutches are as good as the Belleville-washer, steel-basket, hydraulic clutches on the KTM, Husqvarna and GasGas. And, if we were ranking the four Japanese clutches, Suzuki’s clutch would come in last. If you can’t afford a Hinson or Rekluse clutch for your RM-Z450, invest in stiffer clutch springs. 

(4) Handling. You might think that the bike that turns in best would be considered the best handling bike on the track. Not so! The RM-Z450 is at its best at turn-in, but it suffers from serious instability issues at speed, which isn’t just confined to head shake.

(5) Resale value. The low MSRP and the willingness of Suzuki dealers to wheel and deal on the out-the-door price kills the resale value of used RM-Z450s.

The innovative but ineffective BFRC shock needs help. Sending it out for a re-valve is step one.

Q: HOW DID MXA IMPROVE THE 2021 RM-Z450?

A: (1) High-pressure radiator cap. The stock 1.1 kg/cm2 RM-Z450 radiator cap allowed our RM-Z450’s coolant levels to drop during long motos. Twin Air and CV4 offer 1.8 kg/cm2 and 2.0 kg/cm2 radiator caps (even the 1.6 cap from a KX65 is better than the stock RM-Z cap). By increasing the pressure in the radiators, the boiling point is raised to keep the coolant in the radiators.

(2) Heavy-duty clutch springs. Hinson and Pro Circuit make stiffer clutch spring kits for the RM-Z450. The heavier springs improve clutch feel, increase bite on acceleration and outlast the stock clutch plates. We don’t always run all of the heavy-duty clutch springs; sometimes we find that three stiff springs can fine-tune the feel at the lever.

(3) Works Connection Elite clutch perch. With the stiffer clutch springs installed, the clutch pull was harder than stock. To cure this, we swapped the stock Suzuki clutch perch for a Works Connection Elite clutch perch assembly. With three sealed bearing pivots and a better leverage ratio, the Works Connection clutch’s window of engagement was increased. If you have the money, a Hinson or Rekluse clutch is the best fix.

(4) FCP engine mounts. The turning characteristics of the RM-Z450 are second to none. Straight-line stability, on the other hand, is less confidence inspiring. At speed across rough ground, the 2021 RM-Z450 can be scary. Even if you hit the same line lap after lap, the overly rigid chassis will do something different each time. We ran FCP head stays and motor mounts to allow more flex and create a more forgiving ride.

(5) Aftermarket exhaust system. The Suzuki RM-Z450 engine hasn’t seen a major update since 2014. Way back in 2013, Suzuki gave the same basic powerplant a 13-percent lighter piston, DLC-coated piston pin, 0.4mm higher-lift cam, three-dog gears, more magneto power, a redesigned muffler and enlarged air boot. Over the last eight years, the only updates were launch and traction control in 2016. Because of the lack of ingenuity by Suzuki’s engine designers, the aftermarket exhaust pipe manufacturers have been able to fine tune their Suzuki pipes to the nth degree. Whether it is Pro Circuit, FMF, HGS, Akrapovic or DR.D, they can all lift the RM-Z450 power out of the doldrums.

(6) Gearing. We switch the stock 13/50 gearing for 13/51 sprockets. This allows us to use third gear sooner and get more drive out of tight turns to make up for the 4-horsepower hole that Suzuki put us in.

(7) TM Designworks chain guide. The stock RM-Z450 chain guide wears out incredibly fast and will not only eat through the rubber buffer but the metal cage as well. We trust the TM Designworks Factory Edition #1 chain guide. Its solid body is made with “Return Memory” plastic that returns to its original position after being dragged through ruts. It lasts almost indefinitely.

(8) Shock linkage. We ran a longer Pro Circuit shock linkage than the stock 135mm link. The longer link lowered the rear of the Suzuki and stiffened the initial part of the shock stroke, which allowed us to have more options in compression, rebound settings, fork height and head angle.

(9) Ekolu shock. The MXA wrecking crew is not a fan of the stock Showa BFRC shock. It is unique to motocross shocks in that it does not like bumps. In desperation, we mounted WP’s Suzuki-specific forks and Trax shock to our RM-Z450. The WP suspension was a revelation on the Suzuki; however, the price tag was out of the price range of most riders. We felt we could get that by having Brian Medeiros at Ekolu Suspension rework our stock BFRC shock. We chose Ekolu, because last year they built us a hybrid RM-Z450 shock using a 2015 KTM 450SXF shock body combined with a 2017 Showa A-Kit 18mm shock shaft (shortened 2mm to lower the rear end) and re-valved the shock to work much better. Brian took what he learned on his hybrid shock and applied it to the stock RM-Z450 BFRC shock—and that is what we are running in 2021. You can reach Brian at (951) 459-7993. The modded BFRC shock was better balanced, squatted on corner entry, improved rear-wheel traction and didn’t step out when leaned into a bumpy corner. 

Q: HOW DOES THE 2021 SUZUKI RM-Z450 HANDLE?

A: The whole chassis is out of balance. MXA’s goal on the 2021 Suzuki RM-Z450 was to get the rear end down and the front end up. This would kick the head angle out to slow down the steering input. An added benefit of a slacker head angle is that the 2021 RM-Z450 doesn’t head-shake as much. We set the race sag between 105mm and 110mm and slid the forks down into the triple clamps. How far down? Flush would be about right. You’ll know when and where to stop because the chassis will be flatter to the horizon. The front end won’t feel like it is too steep, and you won’t be correcting for oversteer with a lot of counter-steer. 

To help with this, we ran a longer Pro Circuit shock linkage. The longer link lowered the rear of the Suzuki and stiffened the initial part of the shock stroke, which allowed us to have more options in compression, rebound settings, fork height and head angle.

In short, the Suzuki RM-Z450 is raceable, but the chassis is too stiff, too tall, too stinkbug and too steep.

Q: HOW GOOD ARE THE SHOWA COIL-SPRING FORKS?

A: They are much better than Suzuki’s SFF single-spring forks from 2013 to 2015 or the Showa SFF-TAC air forks of 2016 to 2017. Best of all, these coil-spring forks can be easily fixed and are the same basic forks that the Kawasaki KX450 and Honda CRF450 run. Given that misery loves company, a fork that comes on three brands will get more attention than a fork that is proprietary to a single brand. That means that your local suspension guru will have enough experience with the 49mm Showas to set them up right.

Q: HOW GOOD IS THE SHOWA BFRC REAR SHOCK?

A: The Showa BFRC rear shock was a very creative shock when introduced in 2018. As opposed to a conventional shock, the Showa BFRC shock pumps the shock oil up to the top of the shock to be pushed through the valve stack as opposed to the valve stack being plunged through a pool of oil in the shock body. It is a unique idea based on an Ohlins design. Showa claims that its BFRC shock has nothing in common with the Ohlins shock, and that is true, because the Ohlins shock works.

On the drawing board, the BFRC shock looked like a winner, but on the track, it moves too freely. The loose feeling produces different load characteristics from what motocross racers are used to. Every MXA test rider reported that the 2020–2021 shock felt better than it did in 2018–2019 but that it didn’t like to follow rough ground. It is awesome as long as it never sees a bump. We think that the BFRC shock would be great on a Suzuki Hayabusa.

Suzuki shares its basic 49mm Showa fork with both the Kawasaki KX450 and Honda CRF450, but none of the three forks got any updates for 2021.

Q: IS THE 2021 SUZUKI RM-Z450 THE BEST DEAL IN MOTOCROSS?

A: We often hear Suzuki loyalists claim that they could buy the Suzuki and with the money they save make it as good as the KTM, Honda, Yamaha, Husky or Kawasaki. Okay, let’s test that assertion! You could buy an FMF factory 4.1 exhaust system for $900. It would not only get you three more horses; it would knock enough weight off the RM-Z that it would weigh the same 238 pounds as the YZ450F. The kicker? Simple math will tell you that your 2021 RM-Z450’s all-in cost would now be $9399—the same as the MSRP of the GasGas MC 450F, Kawasaki KX450 or Yamaha YZ450F. That popular aftermarket pipe purchase may make your RM-Z450 closer to its competition, but that is only if your competition doesn’t buy the same pipe, gain the same horsepower and lose the same weight as your RM-Z450 did.

The real-world value of a lower-cost machine is in leaving it alone and racing it as is. If you have to modify it, it won’t be a bargain anymore. 

Q: WHAT DID WE HATE?

A: The hate list:

(1) Clutch. None of the Japanese coil-spring clutches (or Kawasaki’s and Honda’s hydraulic clutches) are as good as the hydraulic clutches on the KTM, Husqvarna and GasGas (and you can add in TM, Beta and Rieju). If you can’t afford a Hinson or Rekluse clutch for your RM-Z450, invest in stiffer clutch springs. 

(2) Weight. How heavy is the RM-Z450? Exactly 20 pounds heavier than a GasGas MC 450F, 19 pounds heavier than a KTM 450SXF, 18 pounds heavier than a Husky FC450, 8 pounds heavier than a Honda CRF450, 7 pounds heavier than a Kawasaki KX450 and 4 pounds heavier than a Yamaha YZ450F. If you think that weight doesn’t matter, you are living in fantasy land. Even if it doesn’t matter to your obviously numb sensory system, it does matter to the RM-Z450’s spokes, rims, fork springs, shock spring and frame. Additionally, extra weight mutes braking, acceleration and suspension performance.

(3) Brakes. Suzuki has a 270mm rotor but did not put enough effort into the caliper design to help with modulation. It’s powerful but grabby.

(4) Kickstart. The lack of a kickstarter isn’t the end of the world for the Suzuki RM-Z450, but it also isn’t on the cutting edge of motocross advancement, either.

(5) BNG. In years when a manufacturer doesn’t make any mechanical updates, it would be wise for Suzuki to put more than the minimal effort into the graphics.  

Q: WHAT DID WE LIKE?

A: The like list:

(1) Cornering. The RM-Z450 is at its best on the entrance to turns. In its glory days, the Suzuki was the only bike that turned without effort—not so anymore.

(2) Power. The 2021 RM-Z450 has a well-placed powerband. It doesn’t make much in the way of peak horsepower, but the power it makes is incredibly usable.

(3) Traction control. The 2021 RM-Z450 features a traction-control system that continually measures throttle opening, engine speed and gear position to adjust the ignition timing and fuel-injector duration to stop wheelspin.

(4) Holeshot Assist. Suzuki’s Holeshot Assist Control (S-HAC) offers three mapping modes for different starting-line setups. We’d be happy with one launch control button that didn’t require us to read the owner’s manual to operate.

(5) Mapping. The GET-developed MX-Tuner 2.0 app allows you to remap the Suzuki RM-Z450 from your Apple or Android smartphone—once you jump through some hoops.

Q: WHAT DO WE REALLY THINK?

A: We aren’t going to sugarcoat the 2021 Suzuki RM-Z450. Its claim to fame is that it is the least expensive 450 motocross bike made. It’s not well suspended. It’s not fast. It doesn’t have electric starting. It’s not light. Its clutch is weak and it twitches at speed. Don’t delude yourself into believing that you can buy aftermarket parts to make the RM-Z450 as good as the class leaders. With that strategy, you’ll spend more money and have less bike than buying the high-priced spreads; however, as it sits, it is still the best bargain in motocross, but only if you get the suspension dialed in and leave everything else alone. 

MXA’S 2021 SUZUKI RM-Z450 SETUP SPECS 

This is how we set up our 2021 Suzuki RM-Z450 for racing. We offer it as a guide to help you get your own bike dialed in.

SHOWA COIL-SPRING FORK SETTINGS
After living through the SFF-TAC air fork years, every racer raves about coil-spring forks, but there isn’t a lot to rave about. Yes, they are better than SFF single-spring forks or the terrible SFF-TAC air forks, but that’s setting the bar pretty low. As with all of the late-model Showa coil-spring forks, these forks are too soft for anything but lightweight riders. For hard-core racing, these are MXA’s recommended 2021 RM-Z450 fork settings (stock settings are in parentheses):
Spring rate: 5.0 N/mm
Compression: 10 clicks out (6 clicks out)
Rebound: 12 clicks out
Fork-leg height: Adjust it for the handling, not for the suspension.
Notes: We added 10cc of oil to both fork legs to stiffen the forks in the last 4 inches of travel to stop them from bottoming. This gave us more leeway in dialing in the compression. MXA test riders ran the compression from seven to 12 clicks out, depending on rider speed and track conditions. 

SHOWA BFRC SHOCK SETTINGS
We wish that 2017’s traditional rear shock absorber would fit on the 2018-2021 RM-Z450s. It doesn’t. It should be noted that on the BFRC shock, the compression and rebound are adjusted by counting turns on the bleed screws, not by clicks. The BFRC shock does not have a high-speed compression adjuster. Additionally, there is no rebound adjuster under the shock. Both compression and rebound adjusters are mounted on the piggyback and labeled “Ten” for rebound and “Com” for compression. For hardcore racing, these are MXA’s recommended 2021 Suzuki RM-Z450 shock settings (stock settings are in parentheses).
Spring rate: 54 N/mm
Hi-compression: N/A
Compression: 1 turn out (1.5 turns out)
Rebound: 1 turn out (3 turns out)
Race sag: 105mm (108mm)
Notes: We hated the high-in-the-rear layout of the 2021 RM-Z450. We tried lowering it with massive race sag changes, because we had no other option, but it made the rear end a little harsher (while helping the chassis). We eventually ran a 1mm-longer shock linkage, which lowered the rear of the bike and stiffened the initial shock damping. We recommend the link.

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