Boyesen RAD Valve and Power Wing

What it is

• Complete Reed Block.
• Dual staged reeds.
• Power Wing inserts into carb.

Boyesen has been a staple in the industry for over 40 years providing performance parts and specializing in intake upgrades. Boyesen’s RAD Valve is their patented cast aluminum Reed Block system featuring rubber coated carbon reed petals for a claimed increase in durability. Similarly, their multi-staged reed petals offer better durability while increasing performance across the RPM range with its layered petal design to accomodate for the different RPM ranges experienced while riding. The layered pedals boast a larger pedal with a center port as the base pedal and a smaller top pedal overlapping the cutout. The top pedal is designed to accommodate lower RPMs while the larger pedal reacts at higher RPMs. The Boyesen Rad Valve retails for $179.95.  

In addition, Boyesen’s Power Wing is a simple insert into the carburetor designed to optimise airflow. With its unique design, Boyesen claims the Power Wing provides horsepower gains while improving aerodynamics for maximum velocity generation and power gain. Likewise, the winged design is claimed to smoothen the airflow minimizing disturbance at the needle. The Power Wing retails for $129.95.

How it works

• Increase in power overall.
• Snappy power.
• Clean running.
• Jetting change is necessary.

While building up our Yamaha YZ125 Off-Road Project Bike, we employed Boyesen’s RAD Valves and Power Wing in hopes for a little better power delivery (especially in the lower end) out of the already potent stock YZ engine. And that’s what we got. First off, installation was a breeze. It was no different than installing any other reed cage and working on any two-stroke is petty simple. With the Power Wing you just line it up in the carb and slip the air boot back on. No bolts or screws or anything. Additionally, when we went to pull it back off, it was still lined up perfectly making for a very simple install process that can be done in minutes.

Some two-strokes benefit greatly from aftermarket reed blocks. The different reed petals change the power character and revised air flow in the intake tract can makes for a better performing motor. With the RAD Valve and Power Wing installed on our small bore YZ, we experienced exactly what we we’d hoped for and a bit more. The motor ran very clean and crisp with improved throttle response, but only after a jetting change.

After installing the RAD Valve and Power Wing we felt the need to lean the YZ out with a 420 main jet opposed to the 430 that comes stock, then dropping the needle one leaner, raising the clip to the 2nd position. Before the jetting change, the bike was a little rich off the bottom and would load up quite a bit when riding in technical terrain where screaming the motor wasn’t an option. Almost making the bike unrideable, but we are picky. However, once the jetting change was made, the YZ motor came to life. Overall, there was an increase in power from top to bottom but for sure it was more significant on the bottom end. The power became a little snappier with a slightly more explosive feel where it carried on throughout the rev range. This is a typical result from Boyesen reeds in our experience. Additionally, overrev was good with a small improvement over stock. Likewise, roll on throttle response was noticeably improved where it was able to pick up speed a bit quicker building revs faster making being on the pipe a little less critical (though still necessary on a 125cc two-stroke).  

In addition, we experienced an increase in torque with the Power Wing employed. The bike was able to function in lower RPMs providing some necessary torque for off-road riding conditions. It may not be a 300cc two-stroke, but the torquey feel was greatly appreciated when ridden in tighter singletrack where being smooth on the throttle and minimal wheelspin was necessary and the YZ just kept chugging along even conquering some pretty steep hill climbs.

Overall, the Boyesen RAD Valve and Power Wing are a great add-on for the YZ125 or even any two-stroke for that matter. Improved throttle response and a clean running motor are just some of the benefits along with added torque. Installation is a breeze with a couple common tools. At $310 for both products, it is a bit pricey but well worth it in our opinion. An easy to install performance upgrade that doesn’t sacrifice reliability. We’re all for it!