VForce4Ri utilises a winged air guide that increases air velocity for a dramatic gain in throttle response. Paired with the new winged air guide is a custom intake manifold boot that offers a straighter shot to the intake that greatly enhances both airflow and performance. The VForce4Ri also incorporates carbon fibre reed petals designed to ensure superior reliability and maximum performance.
 
VForce4R offers enhanced reed petal life as well as all the added benefits of the unique VForce reed valve design. Vforce 4 reed valves are the world leading design and performance reed valve with gains in power no other reed valve standard or aftermarket can match. With a twin stack system you get twice the tip surface and with petals only needing to travel half the distance of a normal single stack, Vforce4 air/fuel control is massively improved when compared to stock.
 
Vforce 3 reed valves are the world leading design and performance reed valve with gains in power no other reed valve standard or aftermarket can match. with a twin stack system you get twice the tip surface and with petals only needing to travel half the distance of a normal single stack, Vforce3 air/fuel control is massively improved when compared to stock
 
Vforce4X for the Yamaha YZ250 and YZ250X motorcycles has been designed to offer you exceptional durability and overcome the shortcomings of the stock reed valve system.