Fitment: 2005-2024 YZ125's and 2020-2023 YZ125X's

What's included in the package:

1. Funnelweb Pro-Line Air FIlter

2. Lectron Billetron Carburetor

3. Boyesen RAD Valve

4. Apex Racing Billet 6061 Aluminum Cylinder Head

5. Lectron Tool Kit (optional)

6. Lectron Blue Billet Anodized Bowl Bracket (optional)

7. BeRAD Blue Anodized Billet Brake Reservoir Covers (optional)

8. Boyesen Supercooler (optional)

Want to make your YZ125(X) an absolute weapon? It all starts at the airbox. The Funnelweb Pro-Line Air Filter provides twice the surface area over standard filters. This means more air flow and protection from dust. After air passes through the filter, it's sent through the gate of power: The Lectron Billetron. This carburetor uses a steep bore taper to maximize air velocity, creating a stronger, more responsive pull from your engine. Idle to over-rev, this carb RIPS! With its special metering rod technology, you don't have to worry about swapping jets...It doesn't have them! With this design, the carb also compensates for temperature and elevation changes, so all you need to worry about is twisting the throttle. When that carb opens up, the air rushes through, accelerating into the intake. The Boyesen RAD Valve gulps in air/fuel mixture velocities of over 500mph at over 200 times per second. Its multi-staged reed petal stacks feature Aerospace carbon material interwoven into tension combinations that maximize power delivery and peak horsepower. Integrated into the Rad Valve's seamless interior chamber are 4-way aerodynamic directional dividers that distribute the angled charge evenly without flow loss. Each channel has its own unique Power Profile, scientifically shaped to produce instant, explosive movements of air. Beyond the RAD Valve, the air/fuel mixture enters the cylinder. This is where the Apex Racing Cylinder Head comes in. The OEM cylinder heads large squish clearance can lead to tuning woes, detonation, poor fuel economy and throttle response, and less power. The Apex Racing billet 6061 aluminum head solves all of these issues while giving you an increase in performance where you need it most.

From the airbox to the bang chamber, this performance package brings you everything you need to get your YZ125(X) running like an absolute weapon for motocross, enduro, and anything else you decide to throw at it. This combination of products has proven to be a very powerful, yet reliable relationship. See video: (coming soon). Give your bike the performance it deserves!

Apex Racing Cylinder Head Info:

The SX/XC dome gives a big midrange boost with more power everywhere on the front side of the power curve. It is best suited to tight tracks with lots of jumps out of corners.

The MX dome greatly improves top end power and over-rev at the expense of some low end. This dome works best on fast, flowing tracks.