QuadBoss, QuadBoss Air Cut-Off Valve Kit for Yamaha YFM400 and YFM660R Models B3 Customs Japanese import with limited availability

Japanese import with limited availability in the US

While the 1999 release of their debut project

And there might be a reason for that

Do Those Little Things

QuadBoss, QuadBoss Air Cut-Off Valve Kit for Yamaha YFM400 and YFM660R Models B3 Customs Japanese import with limited availabilityThe QuadBoss Air Cut Off Valve Kit is designed to restore optimal performance in Yamaha YFM400 Big Bear and YFM660R Raptor models from 2000 to 2005. Over time, improperly functioning air cut off valves can stick open or closed, leading to poor engine running conditions and popping sounds during deceleration. This comprehensive rebuild kit includes all necessary components such as O rings, diaphragm, spring, and screws to repair the air cut off valve