2024 CROSS-COUNTRY BATTLE! HONDA CRF450RX VS. KAWASAKI KX450X

The MXA wrecking crew loves to race, and we try to do it every weekend when possible. We mostly race motocross, from local events to AMA Nationals, but we also spend a considerable amount of time competing in off-road events from WORCS to SRA to GNCC to NGPC events to 24-Hour endurance races. 

For these races, we need off-road-specific machinery. Luckily, virtually every manufacturer (save for Suzuki) makes cross-country-ready off-road bikes for 2024. As a rule, they typically share engines, frames, suspension and hardware with the brand’s motocross offerings, which leads us to our comparison test between the 2024 Honda CRF450RX and the 2024 Kawasaki KX450X.

WHAT’S NEW ON THE 2024 KAWASAKI KX450X?

The Kawasaki KX450 was the most highly anticipated new model of the 2024 season, mostly because it was the only all-new bike in the 450 class. Of course, the “X” signifies that the KX450X is a “cross-country” version of the KX450 motocross model, and it benefits from all the updates that the motocross model received for 2024. The KX450 engine has a new cylinder head with a center port and updated valve angles for the intake and exhaust ports to help produce straighter airflow for improved power. 

The frame was also updated to improve front-wheel traction and to make room for the new header pipe, which comes out between the frame’s downtubes instead of out the right side. The traditional Nissin front brake was replaced by the class-leading Brembo system (although the rear is still from Nissin). The new KX450 also has a new electronics system (like Yamaha and now KTM) that allows you to connect your smartphone to your ECU to customize the mapping, traction control and launch control modes. It also has sleeker plastic, a new airbox with a tool-less airbox cover, and a flat-piece-of-toast-style air filter. As an added bonus, the new KX450 and KX450X come with ODI lock-on grips—much nicer than the infamous, vulcanized stock Kawasaki grips.

Q: HOW DOES THE 2024 KX450X OFF-ROAD MODEL DIFFER FROM THE STANDARD KX450?

A: The KX450X is a motocross bike with a handful of off-road features. Here’s the list of differences. 

(1) 18-inch. The 18-inch rear wheel was added to increase cushion and traction. It may sound like the rear tire is now smaller than the 19-inch on the regular KX450, but the 18-inch tire has taller sidewalls that make the actual diameter of the tire and wheel almost identical to the 19-incher. Cross-country and off-road riders prefer the larger air volume and greater contact patch of the 18-inch setup because it adds extra plushness. 

(2) Suspension. The spring rates are the same as stock, but the valving is softer on the KX450X to help navigate the trails. 

(3) Kickstand. It wouldn’t be an off-road bike without a kickstand. 

(4) Tires. The KX450X comes with Dunlop AT81 tires, while the KX450 motocross version comes with Dunlop MX34 tires. 

(5) Chain. The KX450X gets a sealed O-ring chain. 

(6) Price. The 2024 KX450X retails for $10,699, which is $200 more than the KX450 motocrosser. 

Q: HOW DOES THE 2024 KAWASAKI KX450X RUN?

A: We’ve thoroughly tested our KX450X on both track and trail. We’ve raced it at Glen Helen and in Grand Prix-style off-road events. To keep it simple, the new 2024 KX450X engine is lacking in excitement. It’s not terminally slow, but it has a mellow, roll-on style of power that is linear without the slightest sensation of snap. It’s not strong enough to lug third gear in the corners; however, one plus is that second gear does pull longer than before, allowing you to hold second exiting corners more easily. The “X” model didn’t get a spark arrestor; it uses the same muffler as the KX450, which thankfully isn’t as long as the 2023 muffler and has a nice vibrato to it. The KX450X has the same gearing and ECU settings, so it runs just like the motocross model. The mellow power isn’t necessarily a bad thing on an off-road-specific bike; it’s just not what we expected from an “all-new” edition. 

The previous-generation KX450 was snappy and exciting down low. Even though it lacked total horsepower, it felt fast. Kawasaki even offered a KX450SR (Special Racer) in 2022 and 2023. The KX450 “Special Racer” came with polished intake and exhaust ports, a Pro Circuit Ti-6 exhaust system, and reworked ECU settings that gave it an extra 4 horsepower. Amazingly, the 60 horsepower KX450SR still retained a very smooth and linear power profile, which made it great because it wasn’t any harder to ride than the 56 horsepower KX450. It was much faster, but the power rolled on in a manner that was smooth, user-friendly, linear, pleasant and easy to manage. We wish the all-new 2024 KX450 motocross model had inherited some of the KX450SR’s tricks, but it didn’t. 

Don’t get us wrong, the KX450 engine still has plenty of potential. And, for tight and technical off-road riding, the KX450X powerband is great. The cross-country KX450X comes with the same ECU mapping as the motocross model, which is actually not a bad thing since the stock KX450 power is well suited to off-road use anyway.

Q: HOW DOES THE 2024 KAWASAKI KX450X HANDLE?

A: The KX450X handles great, but it’s hard to rate the handling of this bike for its off-road prowess because it doesn’t have an oversized gas tank. Yamaha, Honda, KTM, Husqvarna and GasGas all give their cross-country models oversized tanks, but the KX450X is simply a motocross bike with softer suspension. Once you add an oversized tank, the KX450X will be much heavier, and its nimble cornering prowess might be hindered. With the perimeter frame layouts of both Honda and Kawasaki, the oversized fuel tanks are forced to slide between the perimeter frame rails, leaving no place to add fuel except up and out. Of course, this positions the fuel higher on the bike and farther from the center of gravity.

The Austrian frames have single-back-bone frame layouts that allow oversized gas tanks to slide over the back bone and carry extra fuel down each side of the chassis. If you are looking for the best oversized tank layout, it is on the Yamaha YZ450FX. How so? Yamaha’s backwards engine concept allows extra fuel to be stored in the gas tank underneath the seat. The YZ450FX’s fuel positioning keeps the weight of the fuel centralized and makes it hardly noticeable in motion. 

The Kawasaki KX450X suspension settings are softer than the motocross model’s, but compared to the Honda CRF450RX suspension, the KX450X suspension is stiffer and has more holdup. This is better for faster off-road courses, but worse for tighter trails where you’re swerving through rock gardens or over tree roots. The new KX450 chassis does place more weight on the front end, making it nimbler in the corners, but slightly less stable compared to the previous KX450 chassis.  

Q: WHAT KX450X MODS DO WE RECOMMEND?

A: The new KX450X airbox is extremely choked up. We assume that Kawasaki sabotaged the intake to comply with future noise regulations, which are growing stricter year by year, especially in Europe; however, the small airbox and even smaller air filter hinder power and throttle response. We drilled five holes in the airbox cover, removed the 4-1/2-inch-long rubber grommet under the battery tray, and installed a screen-less Twin Air Powerflow air filter cage and domed Twin Air filter.  

Also, the new KX450 has two baffles in the muffler to keep the noise down, and they contribute to the soft throttle response. The best option is to replace the stock exhaust system with a Pro Circuit Ti-6 exhaust system. It helped the KX450 go from 57.4 to 58.5 horsepower, and it increased torque from 35.5 to 37.2 pound-feet. The Pro Circuit system helped most significantly in the midrange, but it also offered improvement in the low- and high-rpm ranges. The second mod we recommend is a Vortex ECU mapped by Twisted Development. We had our Vortex mapped to work with the Pro Circuit exhaust system. 

Those who don’t want to spend money on an exhaust or ECU can remove the baffles from the stock muffler to find more power. To do this, you must remove the muffler canister and its packing to expose the inner core. We used a 1-1/2-inch butterfly bit, and it fit perfectly in the muffler to drill out the baffles nicely. Then, we blew out any metal left behind. You can do this with the muffler still intact, but you won’t be able to see what you’re doing, so we don’t recommend it. This redneck mod doesn’t help as much as the Pro Circuit exhaust, but it does increase throttle response with a tad more bottom and much more mid- to top-end power. 

We also went from a 50- to a 51-tooth sprocket to help make third gear more useful in tight corner. We also added two links to the chain, which helped us position the rear axle back about 12mm in the swingarm to improve straight-line stability. With the rear wheel farther back, we could position the forks with 2mm showing in the triple clamps, and we could set the sag to 105mm.

WHAT’S NEW ON THE 2024 HONDA CRF450RX?

The Honda CRF450RX didn’t receive any updates for 2024. Like the stock CRF450, it was updated last year with minor frame-rigidity changes, which aren’t noticeable on the track, and extensive engine updates, which are noticeable on the track. The CRF450 engine received a narrower intake-port shape and longer intake funnel, revised cam profile and smaller throttle-body diameter to create a smoother power delivery, increase torque and improve acceleration out of corners. 

Q: HOW DOES THE 2024 HONDA CRF450RX OFF-ROAD MODEL DIFFER FROM THE STANDARD CRF450?

A: Honda offers six different CRF450-based four-stroke models. They have the CRF450R (stock model), CRF450WE “Works Edition,” CRF450R-S (a reproduced 2022 model that didn’t receive the 2023 updates and comes in at a lower price point), the CRF450L (dual sport), CRF450X (trail bike), and this CRF450RX, which is the cross-country version of their motocross race bike. Here’s a list of things that differentiate the CRF450RX from the standard CRF450. 

(1) Suspension. The CRF450RX comes with off-road-specific suspension settings with the same spring rates as the CRF450 but with softer valving. 

(2) Mapping. The ECU map settings are tuned for off-road riding. The bike comes with three maps (standard, mellow, aggressive), three different traction control settings, and launch control.  

(3) 18-inch. The CRF450RX comes with an 18-inch rear wheel. 

(4) Tires. Dunlop AT81 tires come stock for off-road. 

(5) Tank. An oversized, 2.2-gallon fuel tank comes stock, and it requires RX-specific shrouds that have an extra bolt to secure them to the wider and taller fuel tank. 

(6) Protection. The CRF450RX comes with perch-mounted hand guards and a skid plate.

(7) Kickstand. Of course, the CRF450RX comes with an aluminum kickstand. 

(8) Chain. The CRF450RX comes with an O-ring chain. It creates more drag and ultimately lessens power at the rear wheel, but it lasts longer and increases durability. 

(9) Price. These upgrades bring the RX price to $9999, which is $300 more than the CRF450.

Q: HOW DOES THE 2024 HONDA CRF450RX RUN?

A: The CRF450RX is a mellower version than the already-smooth 2024 Honda CRF450 motocross bike. We love the power profile of the motocross model; it’s linear and controllable without any erratic hits or surges. Our test riders felt the cross-country bike was detuned about 5 to 10 percent, which helped increase traction and lesson arm pump in tight and technical sections out on the trail.

Map 1 is the standard map, and that’s where we kept the CRF450RX most when riding off-road; however, when we brought the bike onto the Glen Helen National track to see what it could do, we quickly switched to the more aggressive Map 3 option. Map 2 is the mellow map, and it was best on tight singletrack trails, especially over rocks and roots. The CRF450RX engine is very tractable; it doesn’t have a hard hit. Map 3 allows it to rev more, but it still has a mellower feel than the CRF450. 

Q: HOW DOES THE 2024 HONDA CRF450RX HANDLE?

A: Honda did a great job of tailoring the CRF450RX to its target market, especially in the suspension department; it’s in the proper range. The initial movement of the Showa spring fork is supple and nice, but it does have a harsh top-out feel that is annoying to riders who aren’t used to it. The comfort is nice, and the suspension has a wider range of adjustment than the standard CRF450. You should be aware that the CRF450 has a reputation for having the most finicky suspension on the market. It takes effort to find the right balance with the suspension settings. Equally important, the CRF450RX benefits from a rider who’s wiling to make adjustments from track to track, working to find the sweet spot. Compared to the CRF450, it is harder to mess up the suspension on the CRF450RX. How so? Because of the softer setup, the Showa suspension is more forgiving and offers more versatility. Of course, it is on the soft side for motocross, but our test riders still like it on the moto track. 

The oversized fuel tank is very top-heavy when it’s full. Don’t fill it all the way up unless you plan to ride for a long time. We greatly appreciate that the CRF450RX comes with an oversized tank, but it’s a bummer that it’s so tall and wide. The extra fuel is farther from the center of gravity, making the CRF450RX less nimble while also making it feel heavier than it is.

 Q: WHAT MODS DO WE RECOMMEND?

A: The stock triple clamps have 22mm offset, but our favorite CRF450 mod is to switch out the stock aluminum clamps for Ride Engineering’s CNC-machined, 23.5mm offset split triple clamps. They lengthen the wheelbase slightly and increase stability. On the same note, we drop the forks until they are flush with the top of the triple clamps. This increases stability, lessens head-shake, and puts more weight on the rear end. 

We also recommend installing glue-on grips (instead of lock-on grips) on the Honda CRF450 models. This bike has a tendency to feel harsh, and the forks deliver a hard top-out feel to the handlebars. The glue-on grips increase comfort because there’s more rubber to soak up the energy transferred through the chassis and into the handlebars. 

CRF450RX OR KX450X: WHICH 450 IS BETTER FOR OFF-ROAD?

The Honda CRF450RX comes stock as a true-to-life, off-road race bike, while the KX450X is just a motocross model with an 18-inch rear wheel and softer valving. If you plan to go for longer trail rides or you want to race Grand Prix- or GNCC-style motos, the oversized CRF450RX tank is ready to go, while the KX450X will run out of gas at about the 45-minute mark, depending on how hard you twist the throttle. The mapping of the CRF450RX engine is tailored specifically for off-road, while the stock KX450X is made for moto, but it’s so mellow that it’s good for off-road, too.

The KX450X is a first-year model, and if history teaches us anything, it’s that first-year models always have a teething phase. On this bike, it’s the power that needs to be improved. It can be helped by increased airflow into the engine (i.e., Twin Air Powerflow kit) and more airflow out of the engine (i.e., removing the baffles or installing a Pro Circuit exhaust). The KX450X is $700 more expensive than the Honda, and it’s still lacking a skid plate, hand guards and an oversized tank. But, once you buy those, it will make a great off-road racer.

The CRF450RX is a refined cross-country model that has a friendly power profile and comfortable suspension setup. It’s still a Honda, so it will take effort to dial in the suspension, but the window for comfort is more generous on this bike. Overall, the CRF450RX wins this comparison, because it’s equipped for off-road from the git-go with a skid plate, perch-mounted hand guards, oversized tank, off-road mapping and better suspension settings. The KX450X needs a few more parts before it is ready to race off-road.