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