2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

Ups

• Strong four-stroke engine is responsive and sees weight-saving changes
• Dialing in engine mapping can be done via the Yamaha Power Tuner app
• Chassis is stable and offers a planted feeling
• Range of handlebar adjustment

Downs

• Stiffer suspension spring rates may be necessary for riders weighing more than 150 pounds
• Stock seat is not ideal for taller riders, but taller seat foam options are available
• Air filter surface area is small and requires more frequent maintenance<br/>

Verdict

The YZ450FX is derived from the highly praised YZ450F motocrosser. Its responsive power can be fine-tuned with the Power Tuner app and its stable chassis and improved cornering ability make it a contender in off-road competition.

2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

Overview

The Yamaha YZ450FX is designed for off-road competitions like Grand National Cross Country (GNCC) and Hare Scramble races. It is heavily derived from its motocross sibling, the YZ450F, but comes with a wide-ratio transmission, off-road-specific ECU mapping, softer suspension spring rates, a larger-capacity fuel tank, composite engine guard, 18-inch rear wheel, sealed O-ring chain, fuel level warning indicator, folding aluminum kickstand, and Dunlop Geomax MX3S tires. Whether tackling tight wooded courses or hilly terrain, the YZ450FX is the bLU cRU’s most capable off-road race weapon.

Updates for 2021

Seeing how it experiences updates one year after its motocross counterpart, the latest YZ450FX now has a lighter and more compact cylinder head, different camshafts, new piston, longer connecting rod, larger exhaust head pipe connector, and more efficient breather system. The frame and suspension settings have also been revised. Brake changes consist of a new, more rigid front caliper and compact rear caliper work with new pads and discs.

Pricing and Variants

The 2021 Yamaha YZ450FX is priced at $9,699 and is available in Team Yamaha Blue.

Competition

Key competitors of the YZ450FX include the Honda CRF450RX, Husqvarna FX 450, and KTM 450 XC-F. Others from the 450cc cross-country segment include the GasGas EX 450F and Kawasaki KX450X.

Powertrain: Engine, Transmission, and Performance

Yamaha’s 450 off-road racer is powered by a 449cc liquid-cooled four-stroke that has unique off-road-specific ECU mapping which can be fine-tuned via Yamaha’s Power Tuner app. On our in-house dyno, the FX measured 53 hp and 32.9 pound-feet of torque. After taking it out in the field, test rider Allan Brown wrote that “the power is very responsive and the seat-of-the-pants torque is amazing.” He continued: “The YZ450FX may not pull as long in the rpm range as a KTM 450 XC-F or Honda CRF450RX, but it will easily outdo all of its competition in terms of torque feel.”

2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

Handling

In regard to its chassis and handling, Brown wrote that the FX “has a stable chassis with good cornering ability and a very distinct feel; you quickly realize it is still a full-on competition bike while riding off-road.”

Equipped with a KYB Speed Sensitive System (SSS) 48mm coil-spring fork and KYB shock, the FX flaunts motocross-like settings but with softer springs. Since the FX is 8 pounds heavier than its motocross counterpart, it tends to ride low in the stroke. This can give a false impression of it being stiff, but if you are a rider who weighs less than 150 pounds it might be OK, Brown reports.

“The suspension action is smooth and predictable throughout and offers good stability and control. Only on the biggest of impacts is there any concern of overloading it. We made some adjustments that yielded noticeable improvements in performance and comfort by stiffening the compression and opening the rebound front and rear.”

Brakes

The FX’s brakes have been updated for the 2021 model year. The front Nissin two-piston caliper houses larger 25.4mm pistons. The brake pads are also 22.3 percent larger and make contact with the new front rotor. The rear brake rotor is now 5mm smaller than the previous generation and Yamaha claims the new caliper and hanger assembly are lighter.

2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

Fuel Economy and Real-World MPG

Its 2.2-gallon fuel tank is on par with its cross-country competitions’ tank sizes.

Ergonomics: Comfort and Utility

With four-position-adjustable handlebar clamps, the FX’s offers a total of 36.5mm of fore and aft handlebar adjustability. Overall, Brown states that a 5-foot-10 or shorter rider will fit very well on this bike, but taller riders may want to opt for taller seat foam. Yamaha has a fully assembled unit that is 0.75-inch taller than stock.

2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

Electronics

Engine mapping can be adjusted via the Power Tuner app and preloaded maps are selectable with the handlebar-mounted switch. The engine is electronically fuel injected and the motorcycle is started with a press on the electric starter button which Brown reported starts up quickly in neutral or in gear.

Warranty and Maintenance Coverage

The YZ450FX comes with a 30-day limited factory warranty.

Quality

Overall, our test riders find that the YZ450FX is in fact not “big and lazy,” rather it is comprised of a stable chassis and a monster of an engine, and has a planted feeling and good cornering ability.

2021 Yamaha YZ450FX (Team Yamaha Blue). (Yamaha/)

2021 Yamaha YZ450FX Claimed Specifications

Cycle World Tested Specifications

Source: MotorCyclistOnline.com