CLAMP BOX V-FORCE4 KTM SX/ HUSQVARNA TC 125/150/250 2016-2021

The VForce4 is built on the solid foundation that has made the VForce3 flap valve system a success for over fifteen years. While VForce3 has been continually refined over the years (including the latest VForce3R models), this is a complete redesign of the entire system. We jokingly say, "The only thing we haven't changed is the bolt pattern." However, this is really true. All components needed to manufacture a VForce flap valve system have changed significantly since VForce3.

The sipe cage design now incorporates an airfoil shape in the sipe tip area to increase air velocity from the outer ports. We use a new lamella petal resin, carbon fiber and layup system in our new pre-curved lamella petals. The benefit of the pre-curved flap petal is a better seal in the tip area. The VForce4 also features longer lamella limiters to progressively decrease petal tip speed for increased petal durability. The combined area of the coverslip tip has been increased by over 10%, resulting in increased total airflow. Finally, we reduced the frontal area of the central wing by 15.6%, combined with a more aerodynamic shape.


The new VForce4R models incorporate super modulation of rubber on the lamella surface to dramatically increase lamella petal life while also creating a superior sealing surface.


The new VForce4Ri models include a custom intake manifold boot that offers more direct intake injection, which greatly improves airflow and performance.