Sporting most of the updates of the 2018 YZ 450F, the smaller 250F still offers many of the features that make it popular among riders. We found that very little needed to be done to make this bike race-ready.

2019 YZ 250F Bike Build

Finished bike

Suspension

A bike should be set to the rider’s weight, riding style, and skill level. While Yamaha is well known for using quality KYB brand suspensions, we felt the front forks felt a little soft. We referred the matter to MX1 Suspension in St. George, Utah to have the valving adjusted and the spring rates changed. After all the changes, we found the new sweet-spot to be around 5mm in fork height and 104–105mm in sag. With those changes, the bike felt much more stable in deceleration and hard braking.

Fine Tuned Power

Yamaha set out to increase the engine’s mid-range and top-end power to improve performance over previous years. In succeeding, the engine lost some of the lower-end torque it had before. Fortunately, this was easy to remedy. We installed the FMF 4.1 Anodized Titanium silencer on the stock header and found that it not only increased over-all output, but also kept the bike light.

Another must-have for output is a power tuner map. Yamaha installs a small Wi-Fi unit under the left-hand number plate. Once you’ve downloaded the free power tuner app, you can adjust your mapping from your cell phone. Keefer Testing, Inc. offers an Aggressive map that provides good power at the bottom end without sacrificing your mid and top end performance.

Optimizing Controls

2019 yz250f build handlebar controls

With engine performance at its best, we made the bike comfortable; specifically, we set it up for motocross and WORCS style racing. We added Fasst Flexx 1 1/8” 12° Moto Bend handlebars up front, that includes an isolation damper at the pivot point to mellow shock and vibration on your hands and wrists. We added a one-piece handle bar clamp from Ride Engineering, which has more torsional rigidity to resist twists and bends. The new clamp also has a section cut away to apply a steering stabilizer, accommodating for brands like GPR and Scotts Stabilizers.

Folding Levers
We believe that folding or break-away levers are a must, so we added the Streamline Reflex break-away levers for brakes and clutch. A favorite feature of these levers is the comfortable shapes for improved grip. Add Tusk D-Flex hand guards, a relaxed reach and a controlled pull, and you get confident braking and shifting.

Tusk Race Foot Pegs
While not a must-have, over-sized foot pegs provide an increased platform and a better hold on the bike. Who wouldn’t want more feedback from the track and more control over riding position? We installed the Tusk Billet Race foot pegs, an excellent value in adding grip to our boots. Add to those the Tusk shifter lever and brake pedal, and the improved performance shines.

Full Bike Protection

2019 YZ 250F Skid Plate
Protection for disks is always important, especially when riding off-road. Nicks and dings in the rotor disk shorten the life of your brakes, and debris from off-road riding can interfere with stopping power. To insure clean, protected rotors, we installed the Polisport disk guard to shield not only the rotor, but also the bottom of the fork leg.

Skid Plate
A skid plate is a highly-recommended accessory. We installed the Works Connection Titan skid plate for light-weight protection to our lower frame. Made of tough, injection-molded plastic, this plate will fit like a glove hold its shape while it protects the bike.

Radiator Braces
Radiators are expensive, and are easily damaged in crashes or even small tip-overs. Radiator braces provide reinforcement for your radiators when you push the envelope. We installed the Works Connection braces, which come in a standard finish or a black powder-coat factory finish.

Hole-shot Device

For competition, we added the Works Connection Pro Launch device. A hole-shot or launch device is simply a hook mechanism that locks your forks down as you launch from the gate, holding your front end down keep that wheel closer to the ground. This will provide better control during those first crucial seconds of each race. On your first hard brake, the forks will dip below the mechanism and unhook it, restoring your front-end height. Simple to install and use, this device made a big difference for us.

Putting Power To The Ground

Testing a 2019 Yamaha YZ250F-12
Another upgrade we added was the full Hinson clutch we installed. A bike’s performance relies heavily on the clutch, and Hinson billet components offer reliable, cooler performance and unsurpassed longevity.

Wheels and Dunlop Tires

We installed the Tusk Impact wheels with black rims and blue hubs for a great value and a cool look to the bike. We added sprocket and chain components from Primary Drive for premium response and reliability. Dunlop’s new MX-33 tires with improved materials and structure provided the predictable traction we’ve come to expect from Dunlop.

Personalization


We threw on an Attack Graphics seat cover to help customize the bike. Definitely a good-looking way to make the bike one of a kind, the Attack Graphics seat cover is made from reinforced, double-stitched material for a better grip and rider position.

Attack Graphics provides a full range of completely customizable graphics schemes. We set this bike apart from the others with a combination of our own colors, fonts, and designs. These high-quality vinyl graphics not only dress up the bike, but also protect the plastics from daily wear and tear.

Finishing Touch

Just to finish things off, we added Tusk brand reservoir caps, oil filter cover, and axle blocks to give the bike a little extra luster. Why not shine as you lead through the final lap?

Conclusions

Already an excellent bike, we found ways to coax a little more power from the engine, and improved control by fine-tuning the suspension. In addition to more stability, an upgrade in handlebars also helped handling. We enhanced our increased performance by touching up the wheels, tires, and chain. For good measure, we added a hole-shot device for an advantage at the gate. Radiator guards and a skid plate help protect our ride. We added a more durable clutch and levers as finishing touches, and covered it all in Attack graphics.

For more information on this bike and its potential, watch the First Impressions video covering the stock features and performance.

Tell Us What You Think

Do you like additions? Please let us know what you think, or ask us anything about this Bike Build.

Parts Available at Rocky Mountain ATV/MC

FMF Factory 4.1 Anodized Titanium Silencer with Carbon End-Cap Fasst Flexx 1 1/8″ Handlbar Hinson Complete Billetproof Conventional Clutch Kit
FMF Factory 4.1 Anodized Titanium Silencer with Carbon End Cap Fasst Flexx 1 1/8 Hinson Complete Billetproof Conventional Clutch Kit
Ride Engineering One-Piece Over-sized Handlebar Mount Streamline Reflex Brake Lever Streamline Reflex Clutch Lever
Ride Engineering One-Piece Over-sized Handlebar Mount Streamline Reflex Brake Lever Streamline Reflex Clutch Lever
Works Connection Pro Launch Start Works Connection Radiator Braces Works Connection Titan Skid Plate
Works Connection Pro Launch Start Works Connection Radiator Braces Works Connection Titan Skid Plate
Tusk Folding Shift Lever Tusk Aluminum Break Pedal Tusk Billet Bling Kit
Tusk Folding Shift Lever Tusk Aluminum Break Pedal Tusk Billet Bling Kit
Tusk Impact Complete Front and Rear Wheel Kit Dunlop MX 33 Geomax Soft-Intermediate Terrain Tire Attack Graphics Frame Grip Tape
Tusk Impact Complete Front and Rear Wheel Kit Dunlop MX 33 Geomax Soft-Intermediate Terrain Tire Attack Graphics Frame Grip Tape
Attack Graphics Custom Alloy Complete Bike Graphics Kit Tusk Billet Race Foot Pegs Tusk D-Flex Handguards
Attack Graphics Custom Alloy Complete Bike Graphics Kit Tusk Billet Race Foot Pegs Tusk D-Flex Handguards
Primary Drive 520 Gold-plated MX Race Chain Primary Drive Rear Aluminum Sprocket Polisport Disk and Bottom Fork Protector
Primary Drive 520 Gold-plated MX Race Chain Primary Drive Rear Aluminum Sprocket Polisport Disk and Bottom Fork Protector