In 2017, for the 15th anniversary of the CRF450R, Honda decided to give the bike a makeover. Not just an update or refinement, this was a full model change. For the second time in the CRF450R’s existence Honda threw the baby out with the bathwater and started over.
It’s very rare for a manufacturer to make these types of wholesale changes. In the CRF450R’s life span this is only the third true “full model” change. This bike was introduced in 2002, received major updates in 2005, and by the end of 2008, Honda took a huge gamble and decided to shelve a bike that some people still say could win shootouts. Many people continue to describe the 2008 bike as possibly the best 450cc motocross bike produced of all time.
In 2009, a new CRF450R was introduced which featured several technological improvements. The most significant was a more compact engine with EFI. Unfortunately, this new bike was not well received and took a few years to get the bugs ironed out. In 2013, Honda introduced a new frame, redesigned the bodywork, switched to a KYB PSF (air) fork, and added a dual exhaust, all of which helped improve the chassis and handling. From 2009 to 2016, the chassis of the third and fourth generations of the CRF450R had improved over time, though most riders complained the bike lacked in power compared to the competition’s 450cc models. There certainly had to be times when Honda engineers looked back and said, “What did we do?”
By 2016, Honda created a CRF450R that was pretty good. Maybe not the overall class leader, but it had a few attributes that ranked near the top of its class. The 2016 model was comfortable to ride and felt skinny and very light between your legs. This bike’s ergonomics fit most riders who ranged from 5 feet 4 inches up to 6 feet tall. It also had good handling with quick and agile cornering. However, on the downside, it might have lacked a little in the power department, on braking, and for front suspension.
Entering into 2017, Honda introduced two versions of the new CRF450: the CRF450R and the CRF450RX, which was a big surprise to most people. Honda still sells a great off-road 450cc version, the CRF450X, but with its wide-ratio transmission, headlight, taillight, and carbureted (electric start) engine, this bike is geared a little more toward desert, trail, and long-distance riding. Honda also wanted to have a closed-course off-road (like GNCC) competition bike so Big Red built the “RX” to go alongside the 450R version.
Now you might be thinking, this is about Dirt Rider’s “Bike of The Year” yet this bike didn’t win DR’s 450 motocross bike shootout? Well, we took many things into consideration when awarding this honor. Obviously we factor in the bikes’ overall stock performance but we also consider innovation, technology, and durability..
Honda took another huge gamble with its 450 flagship motorcycle. Since some of its competition—Yamaha, KTM, and Husqvarna—had made big advancements in chassis design and engine power delivery, Honda felt it was about time it stepped up and answered back. Its development focus for the 2017 CRF450 was acceleration by increasing power with maximum rider control while having minimum rider fatigue. The new CRF450R Unicam engine has been developed to achieve overwhelming performance in the first 100 feet of battle, offering increased power output but also allowing unparalleled traction. With these things in mind, Red claimed “Absolute Holeshot.” Although getting around the first turn in the lead is very important, it’s only one part of the race. Winning requires staying in front for the entire moto, which is why Honda engineers designed an all-new chassis with reduced weight and centralized mass.
First, Honda addressed the complaint of lacking power, in comparison to its competition. It implemented knowledge obtained through HRC activity in US, Europe, and Japan and incorporated designs its competition was already using. Continuing with its successful Unicam design, the engineers added finger-follower rocker arms on the intake, similar to the system used by KTM and Husqvarna. This allowed Honda to move the valve train closer to the center of the head. It was able to decrease valve angles and increase airflow and port efficiency a claimed 19 percent on the intake and 10 percent on the exhaust. Because of this increase in port efficiency it was able to increase camshaft intake lobe “lift.” Meaning, when the valve opens, it opens more than the previous design allowing more air to get into the engine.
To maximize this extra air that is able to enter the engine, Honda also increased the compression ratio, going from a claimed 12.5:1 to 13.5:1. This was achieved via a new piston with a revised squish band. Honda also gave the wrist pin a diamond-like carbon (DLC) coating to increase durability.
The normal side effect of more power is more heat and friction. To help keep the cylinder walls cool and the new DLC wrist pin lubricated, Honda increased the amount of oil being delivered via the piston oil jet.
All of these improvements in efficiency would have been lost had Honda not looked into flowing more air into the engine. The biggest hurdle was getting a direct line into the engine. On modern dirt bikes, the placement of the shock creates a serious problem the engineers have to work around. Once upon a time, dirt bikes had two shocks fixed outboard of the rear wheel on the swingarm. This allowed the airbox and carburetor (now throttle body) to be perfectly centered and in line with the engine’s intake. Now, we have single-shock linkage systems with seemingly endless adjustments that we just can’t live without. The engineers have to build airboxes and intake tracts that work their way around this suspension system. This was something Yamaha took into consideration when designing its reverse cylinder head on the current YZ450F and YZ250F motocross bikes.
Most likely, Honda was watching Yamaha’s success with its downdraft intake system and wanted to get as close to that design as possible. Its decision was to raise the intake tract above the shock, creating the straightest downdraft possible without reversing the cylinder head. Fundamentally, whenever you can get more air into the engine, you will make more power. This is why turbo- and superchargers are able to increase an engine’s performance so dramatically.
The Honda engineers didn’t stop at the intake side of airflow; they complemented this increase in efficiency with an all-new exhaust. One of the significant reasons Honda went to the dual exhaust was to move that weight forward. The 450’s have big mufflers and some hang far past the side panel to almost to the tip of the rear fender. Honda was the first to address this with the CRF250R that came with a dual exhaust. Yamaha was next; as an added benefit of the reverse cylinder head, Blue now could wrap the header around the engine before it reached the muffler. This killed two birds with one stone: They were able to keep a reasonably sized muffler while keeping the weight close to the center of the motorcycle. This design also facilitated the longer header which improved torque, hence broadening the powerband. You may remember some aftermarket companies offering longer (drop down) headers for the Honda CRF450; this was to minimize some of these problems. Honda’s factory race team even tested and raced with these for some time.
Honda worked even harder at moving the already compact exhaust system. They were able to relocate it closer to the center without decreasing performance. The new raised intake facilitated more room for the header pipe and in return allowed the forward movement of the mufflers 78mm (3 inches). Now, after the header splits into two, there is a much more gradual bend in the pipe which made significant improvements for the high-compression engine.
With this new engine, Honda designed a new clutch and transmission. A shallower clutch assembly with fewer, thicker plates for a narrower engine width. Gear ratios have all been updated from the primary drive through the five-speed transmission all the way to the final drive.
All of this new engine performance had to be built into an all-new chassis. Honda engineers designed an all-new chassis with reduced weight and centralized mass. Their goal was to have a forgiving chassis that allows riders to more easily extract maximum performance while consistently turning low lap times with the least amount of stress on the rider.
The new, lighter sixth-generation aluminum twin-spar frame with all-new geometry was designed to offer improved cornering performance through reduction of torsional stiffness (the lateral stiffness was unchanged). They also worked on balanced cornering, increased rear wheel traction, lower center of gravity and the concentration of mass.
All of the standard measurements have changed. In an effort to improve steering, the fork angle has decreased by 0.3 degree, resulting in a small decrease in trail that is now 116mm. The triple clamp offset has been increased to 22mm. The center of gravity is lowered by 2.7mm making the bike feel lighter when you’re riding. The seat height is 5mm taller making it a little easier to get from a sitting position to a standing position. The swingarm pivot to rear axle has been shortened by 23.5mm and swingarm pivot to front axle has been increased by 13.1mm. The overall wheelbase is shortened by 10.5mm. The frame, subframe and fuel tank have all received updates to decrease their weight. The radiator shroud width, at their widest point, has been reduced by 30mm.
The three biggest changes in measurements that should be pointed out are: the swingarm pivot to rear axle being 23.5mm shorter, the swingarm pivot to front axle being 13.1mm longer, and the center of gravity height being 2.7mm lower. Race teams work very hard to change these numbers on their racebikes. A small adjustment in these measurements can result in significant changes in rider feedback. What these measurements mean to us, as the rider, is the bike’s front wheel has more leverage over the chassis, assisting to transfer more weight to the rear wheel. The lower center of gravity means the bike is going to feel lighter around the track.
The engineers didn’t want to give up strength but understood the importance of losing weight. They went with an extruded rear section of the subframe that not only saved 200 grams, but the location of which made it significant enough to point out.
Of course attached to the frame is the suspension. For the 2017 model, Honda looked back in history and saw that people certainly seemed to prefer a coil-spring fork over an air spring. It made a great decision; not only did it go back to a coil spring but it upped its game with an A-Kit-type 49mm Showa fork. The goal with these new forks was to improve front end feel, action, and offer simplified adjustability.
Next was the shock. Honda once again had to wipe the slate clean and engineer a way to get the shock positioned correctly while making room for the new downdraft intake. No, they didn’t go back to a twin-shock system. Instead, Honda shortened the fully adjustable Showa shock and lowered the top shock mount by 39mm. This opened space for the downdraft intake and continued in lowering of the center of gravity, while maintaining 12.4 inches of rear wheel travel.
Leaving no stone unturned, Honda introduced this new bike with a race-inspired titanium fuel tank. This new tank offers the same fuel capacity as the 2016 model but weighs 0.13 pound lighter and has a profile that lowers the center of gravity. This seems like it was a win-win decision for the engineers.
The one teaser is that the 2017 Honda CRF450R is electric-start ready but not available as standard equipment. Electric start is available as an accessory (it does come standard on the CRF450RX off-road version). We suspect this was more of a functionality of timing rather than cost. If you remember the all-new 2017 CRF450R was a bit delayed due to the Kumamoto earthquake that hit Japan in April, the RX model was delayed even longer and we suspect the additional delay was to have the standard electric start on the RX model.
Now that you have an understanding of what Honda changed, the big question is, does it work better than the previous CRF450R? Here is some of what Dirt Rider had to say about the new bike's performance:
After riding the 2017 Honda CRF450R we noticed one thing is for certain: There is nothing similar between last year’s model and this year’s. If you own a current Honda CRF450R, you will be greeted by another engine character that you aren’t accustomed to. The 2017 Honda has more torque and throttle response out of corners. Last year’s model lacked the pulling power to match up with some of the other 450s (like the Yamaha and KTM), but the 2017 Honda has that excitement (similar to the Yamaha) down low and pulling power that is better than last year’s Honda model.
Midrange, the Honda pulls extremely well and is a very third-gear-friendly (through corners) machine. Top-end is lengthened from last year’s model and over-rev is stretched out as well. From corner to corner the 2017 CRF450R pulls each gear longer than the 2016 as well as it runs cleaner.
The FI tuning is crisper with zero decel pop. With the 2016 CRF450R we could get it to pop once the throttle is closed (from wide open), but we couldn’t get the new Honda to pop or sputter at all. However, the 2017 is a little finicky at times when starting. Sometimes it fired up first kick; other times it took four to five kicks. Although the 2016 didn’t run as clean on the track it did start sooner than the 2017. The overall feel of the engine is that it has more pulling power and an exciting free-feeling character, better rpm response, and minimal engine-braking.
The fork moves in the stroke freely and still has great damping feeling through the mid-stroke. The end stroke is soft but doesn’t ever bottom violently. We stiffened the compression up only two clicks and this helped tremendously. Each fork click on this fork makes a difference, so when you make changes you will want to make a change one click at a time.
We also slowed the rebound damping one click to help the front end hold up a little more when coming hard into corners. The great news is that there is plenty of front wheel traction and comfort with the Honda’s front end. Last year’s machine struggles with doing this a lot.
The rear of the bike feels similar to the front as it has great squatting ability coming out of corners but was on the soft side on hard high-speed hits. We stiffened high-speed compression a quarter turn and this helped hold the rear up in the stroke coming into jump faces and G-out transitions. Both ends of the machine interact well with each other and felt balanced when out on the track. The track didn’t get too rough on this day, but it was rough enough for us to tell that a spring fork is more consistent and gives the whole bike a more consistent feel. The action of the suspension (along with the chassis) was the most noticeable improvements that Honda made to the 450.
Straight-line stability has improved dramatically as the new CRF450R is not as twitchy coming into corners. The whole feel of the chassis is very solid but remains stuck to the ground much better than the 2016 without a harsh feeling on bump absorption. The 2016 rigid-feeling front head tube area is gone, and the front end doesn’t feel so close to you compared to last year’s model. When riding the 2016 the front tire seems to be very close to you and tucked in, while the 2017 front-end sensation feels a bit more stretched out.
In corners it still has that same front end turning sensation and lays into corners as good as the 2016. The 2017 CRF450R gets you into corners cleaner without a harsh deflection that the 2016 sometimes gave on decel. Side-to-side movement (or flop) feels similar to the 2016, which keeps the Honda very flickable.
As mentioned earlier in this story, this bike didn’t win the 2017 Dirt Rider 450 shootout nor did it win anyone else’s. But we know this bike has lots of potential. We spent 12 months getting to know this bike, testing settings on suspension, chassis, EFI, brakes, and just about anything else we could find. The more we rode the bike, the more we discovered its true potential. The foundation to be a shootout winner is certainly there, and the ‘18 model did win our 2018 MX Shootout. It’s looking like Honda has learned from its mistakes in 2009 and is going to have a motorcycle that is capable of being a potential frontrunner for a few years to come.