Yamaha has been a force in the off-road dirt bike market for more than 50 years dating back to one of the first bikes designed specifically for off-road, the 1968 Yamaha DT-1. Just over a half century later, blue is still looking to bring new innovations to the market with its latest-generation YZ450FX. The YZ450F motocross bike received a complete makeover in 2018, and this year, the FX received all of the same updates along with a few additional off-road-specific features. We spent a few days riding the all-new YZ450FX in Clinton, South Carolina, on the same property that just hosted the 65th running of the Little Brown Jug Enduro. As if that wasn’t special enough, the event was hosted by the land owner, seven-time AMA National Enduro champion and AMA Hall of Fame member Randy Hawkins.
Randy’s team set everything up for some of the best off-road riding and GNCC-style racing conditions possible. AmPro Yamaha team technicians Lucas Statom, Ryan Belue, and Cory MacDonald assembled and prepped as many bikes as we would need, including a few extra so everyone in attendance had a chance to enjoy the day. Yamaha engineers and technicians were also on hand to help with setting up and tuning the bikes so they performed at maximum capacity. Trail boss Todd MacDonald laid out a 20-plus-mile loop with obstacles ranging from single-track, faster-flowing areas, water crossings, and AA-level hill climbs. There was certainly enough to keep riders of all levels entertained.
We were given a rundown of the 2019 YZ450FX and all of its new features, one of which is the Yamaha Power Tuner app. This was first released on the 2018 YZ450F and enables the rider with the option to modify the engine mapping in greater detail than was previously possible and is a completely free application for iOS and Android devices. To purchase a comparable tuner kit for any other brand of motorcycle could range anywhere from $350 to $900, which certainly puts Yamaha at the forefront of engine tuning that is both convenient and free of charge. The Power Tuner app allows users to share settings with others (along with additional information), so the app can also be used to facilitate group communication.
The 2019 YZ450FX received the updated engine that went into the 2018 YZ450F. Some of the key features include a new cylinder head, a high-compression piston with a DLC-coated piston pin, new camshaft profiles, a new crankshaft, and a new 44m Mikuni throttle body, The EFI is controlled by an ECU with YZ450FX-specific base mapping along with a dual-mode engine-mapping switch that is not yet available on the YZ450F.
You might be thinking that a 450 is too big or too heavy for trail riding, but keep in mind, this bike is geared toward off-road competition and GNCC-type racing. GNCC racing has evolved into more open, faster-flowing trails where a 450 has some advantages. If you live on the West Coast and like to race WORCS or GP-style events, then this engine package is exactly what you are looking for.
The YZ450FX is tuned well for these types of conditions. It has a fantastic amount of torque, good bottom-end, strong midrange, and can rev plenty far for single-track riding. The biggest challenge is making the power work best for the conditions. I never used first gear on the course layout we rode in South Carolina. Second gear was good, but if you were not careful, the bike could easily get away from you coming out of corners. If the trail was open, you could almost carry third gear with only a little clutch input. A few of the lighter test riders reported they had absolutely no problem running third gear throughout the single-track. To help control the hard acceleration of second gear, I tried using the optional preprogrammed map 2, which is slightly more mellow, and I found second gear to be more controllable but felt it could still be improved on. So we headed back to the truck to get the 411 on the Yamaha Power Tuner app and how it could help.
I had previously downloaded the app, so all I had to do was pair it to the bike. The Wi-Fi module on the bike has a code that you type into your phone’s Wi-Fi selector and, once entered properly, you are connected. Within the app, you select the model and year of bike, and there are a number of predesigned maps for varying conditions. It was suggested by one of the Yamaha EFI engineers to try the “torquey” map. You can load it into either map 1 or map 2. We loaded it into both the map 1 and map 2 positions because I already knew I wanted to try something different in each position. Keep in mind, when you load a map in either map 1 or map 2, you are adjusting it from the base map, not completely reprogramming the ECU. Shortly after, I grabbed some clean goggles and headed back out to the trails.
The changes were immediately noticeable. Starting out in map 1, second gear still had plenty of grunt on throttle opening but didn’t accelerate through the power nearly as quickly. I could have been more aggressive and used less energy in the corners. At about 20 minutes into the loop, I felt like it was time to try map 2. Again, this selection has the base map and is designed to be a touch more mellow than map 1, meaning even though we put the same torquey setting in both positions, there should still be a noticeable change. My seat-of-the-pants estimate would say it was maybe a 5 to 7 percent decrease and it made the bike even easier to ride. If I were to ride this bike in a race that was one hour or longer, having these maps would be an advantage as I could ride the bike much harder while becoming significantly less fatigued. Keep in mind there are also maps to make the engine even stronger if you are in conditions where you need more power.
This five-speed wide-ratio transmission is just about perfect. Compared to the YZ450F motocrosser, first gear starts much lower, second is about halfway between first and second, third and fourth are very close to being equal, and fifth gear is geared higher and is faster. The gaps between each gear are not all too far in feeling and the broad, torquey power can easily cover them. According to Yamaha, this bike has a claimed top speed of 95.5 mph at 11,500 rpm. Lastly, the clutch feel is very good. There was a slight adjustment after warm-up and it remained consistent all day.
The KYB SSS coil-spring fork and KYB shock have great stock settings. The added rigidity in the frame is matched very well to the suspension settings, offering a good balance of comfort and performance. If you are riding around slow in the pits or on a trail, it seems a little bit firm, but as soon as you start riding at any type of race pace, the suspension works perfectly. I did notice a little of bottoming while riding a few laps on the motocross track, but not enough that I would want to give up the comfort feeling in the single-track areas. For the most part, I was able to set the sag and pretty much forget about the suspension for the remainder of the day.
The chassis is all-new for the YZ450FX, but it is in its second year of production under the YZ450F. That means all of the fine-tuning and adjustments that went into year two of the YZ450F go directly onto the 2019 YZ450FX. Compared to the the previous-generation YZ450FX, this new frame is designed to improve rigidity by a claimed 25-percent vertical, 9-percent horizontal, and 15-percent torsional. Combined with new front engine-mount brackets, upper engine mounts, and swingarm bracket forging, you get a completely new and different feel to how this bike handles.
Yamaha’s 270mm front brake works well and I especially liked the progressive feel. Increasing the braking feel are Dunlop MX3S tires front and rear. The bike also comes with a few traditional off-road features such as an 18-inch rear wheel, D.I.D 520 MXV5 O-ring sealed chain, a redesigned engine guard, a more compact sidestand, and a larger 2.16-gallon fuel tank. It should be noted that this tank is bigger than the 2018 YZ450FX and significantly bigger than the 2019 YZ450F by 0.58 gallon.
The 2019 Yamaha YZ450FX is a serious off-road weapon that instills confidence in the rider. The improved chassis is lighter feeling and its increased agility are what this bike needed to take it to the next level. The ergonomics are okay, but if I could, I would like to try seat form that’s taller and flatter in the middle of the seat to help me get less of a sit-in feeling and more of a sit-on feeling. The stock suspension settings are right in the ballpark for me. Lastly, the engine makes good, usable power and is very easy to adjust to whatever conditions you are riding in.
|ENGINE||449cc, liquid-cooled, single-cylinder four-stroke|
|FRAME||Aluminum bilateral beam|
|FRONT SUSPENSION||KYB Speed Sensitive System (SSS) coil-spring fork adjustable for compression and rebound damping; 12.2-in. travel|
|REAR SUSPENSION||KYB shock adjustable for spring preload, high-/low-speed compression damping, and rebound damping; 12.5-in. travel|
|FRONT BRAKE||Nissin single 270mm disc w/ twin-piston caliper|
|REAR BRAKE||Nissin single 245mm disc w/ single-piston caliper|
|SEAT HEIGHT||37.6 in.|
|FUEL CAPACITY||2.2 gal.|
|CLAIMED WEIGHT||256 lb. wet|