2018 Honda CRF450RX Review

This year marks the second year of Honda producing the CRF450RX, which is Big Red's flagship off-road bike designed to be raced in enduros, hare scrambles, and GNCCs. Sharing many similarities to the CRF450R—which took top honors in Dirt Rider's 2018 450 MX Shootout—the CRF450RX has a few distinct components that make it more off-road oriented and suited for the trails including different engine hangers that allow for more flex, softer suspension settings, an 18-inch rear wheel, oversize fuel tank, kickstand, and Dunlop AT81 tires. The 2018 model included a couple of changes from last year's bike, such as an upgraded lithium-ion battery to reduce weight and increase performance along with the removal of the kickstarter to further decrease weight.

The CRF450RX engine packs plenty of power, as evidenced by our in-house DynoJet dynamometer, where Big Red's flagship off-roader made 52.7 hp at 9,440 rpm backed up by 33.6 pound-feet of torque at 7,450 rpm. On the trail, the Unicam engine is crisp, responsive, and feels almost two-stroke-like in the way that it has very little flywheel effect and therefore revs quickly. This has upsides and downsides, with the latter being most noticeable in the lower-speed, tighter sections of the trail. In these situations, the quick-revving powerplant can, at times, feel a little too responsive and the bottom-end power can be a little jerky Also, one of our test riders experienced some occasional clutch fade in these slower areas of the trail.

Once past the lower rpm, the engine’s positive traits quickly become evident as the RX pulls very hard in the midrange and top-end, making the engine work best in higher-speed sections and when hillclimbing. We were amazed and pleased at how exceptionally well the Honda pulled up long, steep hill climbs and continued to do so the farther we ascended. Also, the 2.2-gallon fuel tank is large enough for a fairly long ride, as one of our test riders was able to put in 85 miles before the tank was nearly empty. At the same time, the oversize tank is not cumbersome to where it interferes with the rider while maneuvering on the bike.

The Showa 49mm coil-spring fork and Showa shock have a very performance-oriented feel on the CRF450R motocrosser, and we found them to offer more comfort on the CRF450RX with the softer off-road-specific settings. Both units have a good amount of progressivity and soak up the small chop with ease and absorb the larger impacts well too. The front end tracked and stuck the ground while staying straight when riding over small rocks scattered across the trail. In the rear, being that it’s set up on the softer side, we noticed the shock would occasionally come close to bottoming out on abrupt impacts, but it was very minor and only happened when we mistimed a whoop or suddenly came upon a G-out unexpectedly.

One of the reasons the CRF450R motocross bike is so well-liked by our test riders is because of its lightweight-feeling and nimble chassis, and the CRF450RX shares many of those positive qualities. The RX corners exceptionally well and is very responsive to rider input, which is a major contributing factor to its lightweight feel. These qualities can work against the bike as it can be a bit unpredictable at times because of how easily and quickly it reacts to the rider’s actions and movements. At times, the slightly rigid chassis prevents the rear end from feeling planted when riding over obstacles and we also noticed that, on the opposite end of the spectrum to the bike’s incredible ability to climb hills, the RX occasionally feels a bit unstable going down hills. However, this was mostly noticeable on very steep descents, and not so much on an incline you would find on an average trail ride.

The Honda CRF450RX has proven to be a reliable off-road machine with a high level of quality you would expect from Honda as far as fit, finish, and having good components. The RX possesses racebike-like qualities in stock trim with a fast-revving, powerful engine that has loads of power on tap, and then some, to climb just about any hill you put in front of it. The Showa 49mm coil-spring fork and Showa shock offer a great balance between comfort and performance for a wide variety of weights and skill levels. The chassis certainly has its upsides and a few aspects that could be improved upon to make it more suitable for off-road. Like the CRF450R, the CRF450RX is a blast to ride, and when you’re riding at or near the best of your abilities, it works incredibly well. Lastly, because it shares so many of the same components as the CRF450R and has many similar performance characteristics, the CRF450RX is more than capable of being used as a bike that can hit both the trails and the motocross track.

Allan Brown   Age: 47, 5'10", 175 lb., Off-Road Intermediate

Honda has invested a lot of time, energy, and money into their new generation 450 competition motocross bike. With some minor updates from 2017 to 2018, the CRF450R is now winning shootouts. You would assume a bike that is so good on the track would be pretty good in off-road completion also, but in my opinion, some of the bike’s strengths on the track are somewhat overpowering on the trails. Its super-responsive engine paired with a chassis that’s ultra-sensitive to input can make it somewhat of a handful in tighter, rocky, or slippery conditions.

I spent a lot of time on the 2017 CRF450RX and was hopeful Honda would make similar improvements on it as they did for the CRF450R model. The RX did get a new, smaller, and lighter lithium-ion battery, and in addition to being lighter, the new battery also gives you just a little more room to access the air filter. Additionally, they removed the kickstart mechanism to cut even more weight. These changes add up to a claimed 4-pound weight reduction. Lastly, they also made some updates to the ECU mapping to improve rideability.

After another test pilot did some initial photos and a day or two of test riding, it was my turn. Lucky for me there was no need to worry about break-in and I could start hammering as hard as my skills would let me. Going off of what I remembered about the 2017 model, it required a bit of a “take the bull by the horns” riding style, so I did just that. I went straight out to some trails I know very well and started to push the bike as hard as I could.

The first thing I notice whenever I throw a leg over one of these new Honda chassis is how light they feel. For a bike that weighs 255 pounds wet, you would guess it weighs much less. Its lightweight feel and agility lend it more to feeling like a two-stroke than a four-stroke.

While riding some flat single-track with sections of small rocks and some sand rollers, I approached what is the CRF450RX’s strongest area: big hills. This bike can climb. The combination of a light-feeling chassis and strong engine can make a novice look like an expert.

I continued to ride through many familiar areas trying to get a good read on the RX. In flowing trails with a lot of corners, this bike is a lot of fun. I like the feel of the Honda brakes, levers, and handlebar, but I’m not a fan of the stock grips as they seem to be on the larger side. For the most part, after day one I was pleased and felt the bike to be quite enjoyable.

As I geared up for day two, I knew it was going to be a big day of riding and I would be putting the RX through some nasty sections. The group I was riding with had a 125-plus-mile day planned with no option of turning back. We would need to carry some gas and have a midday gas stop.

Everything went as expected as the day began. We rode through varying conditions for about the first hour, and then things started to get interesting when we began to get into some rocky sections. The drawback to the CRF450RX’s light and nimble feel is its lack of a planted or dead feel, so when you get into rocks that vary in size from baseball to soccer ball, the rear wheel wants to move around under you making the bike very unstable. I really had a hard time with the rear wheel bouncing out from underneath me, so to compensate, I would make every effort to stand and grip with my legs at all times.

As the ride went on, the rocks got bigger. We began to climb a mountain that had some fun switchbacks and steep rock climbs. The bike worked well in the uphill switchbacks as the weight transfer to the rear wheel helped keep it planted. Riding up ledges and rock faces was easier than expected thanks again to the quick-responding engine and light-feeling chassis.

When we reached our scheduled gas stop we had ridden 85 miles and the CRF450RX fuel tank was dry. I felt the bike starting to run out, so I coasted down the last big hill for a mile or so. At the bottom, the bike did restart and got across the flats to the gas stop.

After refueling we rode some open desert. In the desert sand, I found it better to ride in a more neutral position not leaning back as much as normal because it didn’t put enough weight on the front wheel.  Even in the sand washes where I would normally want to be way back, the bike worked better with a more neutral or forward body position. The suspension worked reasonably well at speed and the engine pulled me out of trouble whenever I mistimed a sand roller or two. For those of you who like to ride at high speeds, this bike is only a five-speed, so you may want to put a smaller rear sprocket on—although that is going to hurt the rideability of first gear in the tight rocky sections, so it’s give and take.

After riding the 2018 CRF450RX for a total of 165 miles, I feel like it’s maybe a touch better than the 2017 model. It has a very light and nimble feel, its cornering ability is fantastic, and the engine is crisp and responsive. Honda took a fantastic motocross bike, added a big tank, an 18-inch rear wheel, and said, “Here’s our off-road bike.” It could revise a few more settings and make this bike much better. While it’s a good bike, I don’t think it will be winning any off-road shootouts. When the conditions are good, the bike is amazing, but for fast and aggressive off-road riding, it’s a bit of a handful. When it gets away from you, there is little chance of getting it back and you are either crashing or going for a wild ride off the trail.