The Honda CRF450RX is in its third year of production in 2019 and is campaigned by Trevor Stewart in the WORCS series and Trevor Bollinger in the GNCC series. Like the CRF450R motocross bike, the CRF450RX features several updates to the engine and chassis. Additionally, it boasts several off-road-specific components including a 2.2-gallon resin fuel tank, an 18-inch rear wheel, a kickstand, a sealed chain, and different suspension settings than that of the CRF450R motocross bike.

Engine

The CRF450RX features many of the same changes the CRF450R motocrosser received for 2019. The revisions made to the engine include an updated cylinder head design, a larger-diameter header pipe, a revised clutch lifter and pressure plate, a new scavenge pump design, a new piston oil jet, a new shift sensor, and updated engine mode select options. Also, the total tube length of the exhaust system (from exhaust port to muffler end) is increased by 98mm (approximately 3.9 inches) on the right and 187mm (approximately 7.4 inches) on the left.

2019 Honda CRF450RX
The Honda CRF450RX is in its third year of production in 2019.Jeff Allen

Sharing the same engine as the CRF450R, the CRF450RX does not lack power. The major engine components are used on both bikes with only EFI mapping to tune the power more for off-road racing. The updated cylinder head improves torque while the EFI mapping has broadened the power and made the bike easier to ride. Overall, the power is smoother and the jerky feeling of the 2018 model is reduced. According to Honda, they made a conscious effort to create three more distinct maps that are selectable on the fly. We switched maps several times to try and feel the differences. On the motocross track, the differences between the three maps feel minimal. All three of them worked well with each having its positives and negatives. A noticeable trait of the 2019 engine is that it revs free with minimal engine-braking regardless of what map is selected.

redesigned the swingarm
Honda made changes to the aluminum frame to improve traction and cornering feel, and to reduce weight. It also redesigned the swingarm to have better rigidity characteristics and be lighter. The shock linkage has also been changed to work with the new swingarm.Jeff Allen

The engine settings on last year’s CRF450RX left some room for improvement when you went off the track and onto the trails. With the 2019 model, the added torque and smoother power delivery made the bike much more enjoyable to ride. Map three is the preferred map for when the trails are slightly more open and flowing. In tighter sections when riding mostly in second gear, maps one and two work best. On rocks or slippery terrain, map two is ideal as map three made it a little too easy to spin the rear tire. One area the engine could still use some improvement is in the flywheel effect, or the ability to lug the engine at very low rpm and not stall. Honda improved this by about 40 percent on the 2019, but we would still like to test a heavier flywheel to see if that would help the engine’s flywheel effect.

Hondas have always been the easiest bikes to shift, much of the time without even using the clutch, and the 2019 CRF450RX did not let us down. The gear ratios are good, but for an off-road bike, a six-speed transmission would be preferable. The clutch action was smooth and fairly consistent, but we did experience some clutch fade when the engine got unusually hot. This was not completely unexpected though because we were having fun riding in slower and rockier sections and were really using the clutch a lot.

2019 model has an updated cylinder head design
The 2019 model has an updated cylinder head design, a larger-diameter header pipe, a revised clutch lifter and pressure plate, a new scavenge pump design, a new piston oil jet, a new shift sensor, and updated engine mode select options. Also, the total tube length of the exhaust system (from exhaust port to muffler end) is increased by 98mm (approximately 3.9 inches) on the right and 187mm (approximately 7.4 inches) on the left.Jeff Allen

Suspension

The changes made to the suspension components on the 2019 CRF450RX include revised settings in the Showa 49mm coil-spring fork and Showa shock, a revised shock linkage, and the use of lower-friction oil in the fork, all of which complement the new chassis. The settings are firm enough that the bike handled the motocross track well, but still soft enough that you can get into some tighter, rocky areas without getting bounced off your line. Those who ride mostly off-road may want to open the adjusters to get even more comfort. If you ride at the motocross track a lot and/or on faster flowing trails and weigh more than 175 pounds, stiffer fork springs and possibly a firmer shock spring would be best, but the stock valving seems very usable.

suspension settings
The suspension settings are firm enough to handle the motocross track well, but still soft enough that you can get into some tighter, rocky areas without getting bounced off your line.Jeff Allen

Chassis/Handling

The chassis of the CRF450RX has been refined with changes to the aluminum frame designed to improve traction and cornering feel, and to reduce weight. The swingarm has also been updated to have better rigidity characteristics and be lighter, and the shock linkage has been changed to work with the new swingarm as well. The front brake caliper is lighter and uses a pair of 30mm and 27mm pistons, whereas the previous model used two 27mm units, intended to improve braking performance along with an updated front brake hose.

2019 Honda CRF450RX
The added torque and smoother power delivery make the CRF450RX much more enjoyable to ride.Jeff Allen

The top triple clamp now has two handlebar-holder locations along with a new Renthal Fatbar that is positioned 15mm (0.6 inch) lower than the previous models. Additional chassis changes are redesigned fork protectors with more coverage, black rims, and newly shaped footpegs that are 20 percent lighter and are designed to shed mud more easily.

We spent a lot of hours in the saddle of the 2017 and 2018 CRF450RX trying to get the chassis figured out. Rear wheel position, suspension settings, and lowering links were just a few of the things we tested. While all of these adjustments and modifications changed the bike, some improved it, but none eliminated the unpredictability of the CRF450RX when you got into a bad situation. This resulted in it being hard to feel confident on the bike and made it feel like you were riding in more of a defensive mode.

EFI mapping
The updated cylinder head improves torque while the EFI mapping has broadened the power and made the bike easier to ride.Jeff Allen

The 2019 model immediately allowed us to be more confident on it. It feels more like each part of the bike works in conjunction with its counterpart. The new chassis is much more forgiving and rider comfort is dramatically improved. One of our biggest dislikes about the previous model was the pitching of the bike, and that has been just about completely eliminated on the 2019 model. The rear wheel can hit rolling or square-edge bumps and the impacts are absorbed without feeling like it wants to drive the front wheel down. Front wheel feeling is also greatly improved. This bike is a front-wheel-steering bike and the more you can get over the front of it, the better it will handle. The chassis changes seem to have put much more weight on the front wheel, meaning that overall, the bike is easier to turn. The new Renthal Fatbar bend and position are much more comfortable as well. This also means you don’t need to an buy aftermarket handlebar and bar mounts if you want to run a 1-1/8-inch bar on this bike.

new chassis
The new chassis is much more forgiving and rider comfort is dramatically improved.Jeff Allen

One thing Honda didn’t change was the fuel tank. While an off-road bike needs a bigger tank, the design of this one does not seem to use the space available as efficiently as it could. Aftermarket companies like IMS have some optional tanks now available for the CRF line that hold the same amount as the RX, but are much slimmer. This is significant because this is a front-wheel-steering bike and the large Honda tank makes it a touch harder to get as far forward as possible.

2019 Honda CRF450RX
The 2019 Honda CRF450RX is much more balanced in its ability to be good on the motocross track, and now more competitive in off-road.Jeff Allen

Conclusion

We are very excited about the 2019 Honda CRF450RX. Overall, the changes to the bike make it at least 70 percent better. The 2017 and 2018 models had some room for improvement and Honda touched on almost every area that needed work. The 2019 model is much more balanced in its ability to be good on the motocross track, and now more competitive in off-road. The chassis seems more forgiving when you make a mistake and easier to recover when it starts to get away from you. The engine’s power is increased and more usable as well. We look forward to putting more time on the 2019 CRF450RX as it’s a blast to ride and significantly improved over its predecessor.

TECH SPEC

 
PRICE $9,599
ENGINE 449.7cc, liquid-cooled, single-cylinder four-stroke
TRANSMISSION/FINAL DRIVE 5-speed/chain
MEASURED HORSEPOWER N/A
MEASURED TORQUE N/A
FRAME Aluminum twin-spar
FRONT SUSPENSION Showa 49mm coil-spring fork adjustable for rebound and compression damping; 12.0-in. travel
REAR SUSPENSION Showa Pro-Link shock adjustable for spring preload, rebound and compression damping; 12.3-in. travel
FRONT BRAKE Nissin single 260mm disc w/ twin-piston caliper
REAR BRAKE Nissin single 240mm disc
RAKE/TRAIL 27°25’/4.6 in.
WHEELBASE 58.2 in.
SEAT HEIGHT 37.8 in.
FUEL CAPACITY 2.25 gal.
MEASURED WEIGHT 255 lb. wet
AVAILABLE Now
CONTACT powersports.honda.com