Reed Valve V-FORCE 4R Yamaha YZ125

V-FORCE 4 valve

The V-Force reed valve stands out as a groundbreaking advancement in the world of two-stroke engines. Initially designed for motocross, it subsequently gained prominence across diverse disciplines and for a variety of vehicle models.

The VForce 4 is a a redesign of the well-known VForce 3 and the latest development from American brand Moto Tassinari.

ADVANTAGES VFORCE 4 reed valve

The VForce 3 from Moto Tassinari features a unique architecture with a V-shape in the middle. This special design allows for using twice as many reeds (4 instead of 2), resulting in improved cylinder filling. This in turn improves throttle response and performance at low RPMs.

The new V-Force 4 version adopts the principle of the V-Force, but has been completely redesigned. It is therefore a genuine redesign with the following improvements:

• Airfoil technology with aerodynamic cage tip for increased air speed
• Preformed reed petals for better sealing at the valve tip
• Wider valve cage for maximum air flow
• Longer stops to progressively slow down the speed of the reed tips and thus increase the reed life
• The surface area of the petals has been increased by more than 10 %, resulting in a higher air flow.
• The front surface of the middle wing has been reduced by 15.6% and made more aerodynamic.

In addition, the surface of the cage has been over-molded with rubber to further increase the service life of the valve petals and also to create a larger sealing surface.

The new VForce4Ri models are equipped with a custom-made intake sleeve that ensures a directed airflow to the intake, which significantly improves airflow and performance.

Reed valves for scooter, motorcycle and moped

The reed valve is an integral part of the intake system. It usually sits under the intake manifold.

How does a reed valve work?

The reed valve is usually V-shaped and is equpped with two blades. When the reed valve is opened, mixture will flow; when the reed valve is closed, the flow is significantly reduced. The flow is controlled by the opening of the carburetor slide, which controls the amount of mixture and affects RPM.

What kind of reed valve?

The type and shape of the reed valve can affect engine performance. Common types include the V-Force reed valve in a W-shape with 4 reed petals, and oversize versions with more volume than the original reed valves.

Adjusting the reed valve

You can improve engine output by using petals in different thicknesses, or by using a stuffer or a reed valve spacer. You can influence the mixture flow, which can affect the overall performance of the engine.

Note: When installing also change the intake gasket!