Yamaha YZ450F (2018–2021) Review: A Motocross Powerhouse Refined
Introduction
The Yamaha YZ450F needs no introduction in the motocross world. From 2018 to 2021, this generation solidified its reputation as a track weapon that balances raw power with surprising refinement. Designed for riders who demand precision and reliability, the YZ450F isn’t just a bike—it’s a platform for pushing limits. After spending time aboard this machine, it’s clear why it remains a favorite among amateur racers and seasoned pros alike. Let’s break down what makes this generation stand out.
Engine Performance: Controlled Fury
At the heart of the YZ450F lies a 449–450cc liquid-cooled, single-cylinder four-stroke engine. Yamaha’s DOHC design with titanium valves ensures rapid revving, while the Mikuni® fuel injection system (44mm throttle body) delivers crisp throttle response. The compression ratio evolved from 12.5:1 in 2018 to 13.0:1 by 2020, sharpening mid-range punch without sacrificing tractability.
On the track, the engine’s character is unmistakable. Twist the throttle, and power builds linearly—no sudden hits, just a surge that pulls hard from low RPMs to the 11,500 RPM redline. The 5-speed gearbox shifts with a satisfying click, though the ratios feel optimized for tight MX circuits rather than open terrain.
A standout feature in later models (2020–2021) is Yamaha’s Power Tuner app, which lets riders adjust fuel/ignition maps via smartphone. Paired with launch control, it’s a tech-forward touch that caters to tinkerers. For stock settings, the bike defaults to a balanced map that works well in most conditions—no laptop required.
Handling and Suspension: Precision Meets Plushness
Yamaha’s bilateral beam frame (aluminum in 2021) strikes a perfect balance between rigidity and flex. The 1481–1486mm wheelbase (58.3–58.5 inches) feels planted in corners yet nimble enough for quick directional changes.
The KYB Speed-Sensitive System is the star here. The fully adjustable front fork and rear shock absorb everything from sharp square-edge bumps to hard landings. Even at speed through choppy sections, the chassis remains composed. For aggressive riders, stiffening the compression damping transforms the bike into a razor-sharp tool for attacking rhythm sections.
Dunlop® MX3S® and MX33® tires (depending on the year) provide predictable grip. Run at the recommended 1.0 Bar (14.5 PSI), they’re versatile across hardpack and intermediate terrain. The hydraulic brakes lack initial bite compared to competitors but offer excellent modulation—ideal for scrubbing speed before corners.
Ergonomics and Comfort: Built to Move
At 111–112kg (245–247 lbs) wet, the YZ450F feels featherlight when flicked sideways. The seat height dropped from 975mm (38.4") in 2018 to 965mm (38.0") by 2020, making it more accessible without compromising ground clearance (330–335mm / 13.0–13.2"). The two-tone seat’s grippy texture locks you in during acceleration, though it’s firm for long motos—a common trade-off in MX.
Rider triangle is neutral. Narrow shrouds and a flat fuel tank (6.06–7.57L / 1.6–2.0 gal) make it easy to shift weight forward. Standing up reveals a handlebar bend that suits most riders, though aftermarket options can fine-tuning the cockpit.
Competition: How Does It Stack Up?
The 450cc motocross class is fiercely competitive. Here’s how the YZ450F compares:
- KTM 450 SX-F: Lighter (108kg / 238 lbs) and packed with tech like traction control, the KTM feels more agile. However, the Yamaha’s engine is smoother, and its suspension handles harsh landings better.
- Honda CRF450R: Honda’s chassis is razor-sharp, but its aggressive powerband demands skill to master. The YZ’s linear delivery is friendlier for intermediate riders.
- Kawasaki KX450: The Kawi’s adjustable handlebar mounts and air fork appeal to customizers, but Yamaha’s KYB suspension has a more consistent feel mid-stroke.
The YZ450F doesn’t dominate in any single area—it wins with balance. Beginners appreciate its predictability, while pros exploit its tunability.
Maintenance: Keeping the Beast Alive
Owning a high-strung MX bike means staying on top of maintenance. Here’s what YZ450F owners need to know:
- Oil Changes: Use 10W-30 to 20W-50 (API SG or higher). Capacity is 950ml with a filter—change every 10–15 hours.
- Valve Checks: Titanium intakes (0.10–0.17mm / 0.004–0.007") and exhaust (0.15–0.22mm / 0.006–0.009") should be inspected every 20–30 hours. Shims rarely need adjustment if you avoid over-revving.
- Chain Care: The 520 chain requires regular lubrication. Consider upgrading to a DID® VT2 for durability.
- Cooling System: Replace coolant (1.0L / 34 oz) annually. A high-performance option like Engine Ice® improves heat dissipation.
- Spark Plugs: NGK LMAR8G or CPR8EAIX-9 iridium plugs last longer under heavy load.
For MOTOPARTS.store shoppers, we recommend:
- ProTaper® handlebars for personalized control.
- Twin Air® filters to maximize airflow.
- SKF® fork seals for suspension longevity.
Conclusion: A Legacy of Excellence
The 2018–2021 Yamaha YZ450F isn’t just a bike—it’s a statement. Whether you’re blasting out of corners or fine-tuning maps via smartphone, it rewards skill without punishing inexperience. While newer models have emerged, this generation remains a benchmark for riders who value versatility. Pair it with the right aftermarket upgrades, and it’ll dominate tracks for years to come.
Ready to elevate your YZ450F? Explore MOTOPARTS.store’s curated selection of performance parts and start building your dream machine today.
Specifications sheet
| Engine | |
|---|---|
| Stroke: | Four-stroke |
| Max power: | 49 kW | 66.0 hp |
| Max torque: | 63 Nm |
| Fuel system: | Mikuni® fuel injection, 44mm |
| Max power @: | 9500 rpm |
| Displacement: | 450 ccm |
| Fuel control: | DOHC |
| Max torque @: | 7000 rpm |
| Bore x stroke: | 97.0 x 60.9 mm (3.8 x 2.4 in) |
| Configuration: | Single |
| Cooling system: | Liquid |
| Compression ratio: | 13.0:1 |
| Number of cylinders: | 1 |
| Valves per cylinder: | 4 |
| Dimensions | |
|---|---|
| Wheelbase: | 1486 mm (58.5 in) |
| Dry weight: | 112 |
| Wet weight: | 111 |
| Seat height: | 965 mm (38.0 in) |
| Overall width: | 826 mm (32.5 in) |
| Overall height: | 1275 mm (50.2 in) |
| Overall length: | 2184 mm (86.0 in) |
| Ground clearance: | 330 mm (13.0 in) |
| Fuel tank capacity: | 6.2 L (1.64 US gal) |
| Drivetrain | |
|---|---|
| Chain type: | 520-series |
| Final drive: | chain |
| Transmission: | 5-speed |
| Rear sprocket: | 49 |
| Front sprocket: | 13 |
| Maintenance | |
|---|---|
| Rear tire: | 120/80-19 |
| Engine oil: | 10W-30 or 20W-50 |
| Front tire: | 80/100-21 |
| Brake fluid: | DOT 4 |
| Spark plugs: | NGK LMAR8G, NGK CPR8EA-9, or NGK CPR8EAIX-9 |
| Coolant capacity: | 1.0 |
| Engine oil capacity: | 0.95 |
| Engine oil change interval: | Every 15 hours (motocross use) |
| Valve clearance (intake, cold): | 0.10–0.17 mm |
| Valve clearance check interval: | Every 20-30 hours (racing conditions) |
| Valve clearance (exhaust, cold): | 0.15–0.22 mm |
| Recommended tire pressure (rear): | 1.0 bar (14.5 psi) |
| Recommended tire pressure (front): | 1.0 bar (14.5 psi) |
| Additional Features | |
|---|---|
| Clutch: | Multiplate wet clutch |
| Tuning: | Power Tuner via smartphone (2021 models) |
| Ignition: | TCI (Transistor Controlled Ignition) |
| Launch control: | Available (2021 models) |
| Chassis and Suspension | |
|---|---|
| Frame: | Bilateral beam frame, aluminum |
| Trail: | 119 mm (4.7 in) |
| Rear brakes: | Single 240 mm disc, hydraulic |
| Front brakes: | Single 240 mm disc, hydraulic |
| Rear suspension: | KYB® single shock; fully adjustable |
| Front suspension: | KYB Speed-Sensitive System, inverted fork; fully adjustable |
| Rake (fork angle): | 27.0° |
| Rear wheel travel: | 318 mm (12.5 in) |
| Front wheel travel: | 310 mm (12.2 in) |
