X-Head’s Durability

via email from Will –
X-Heads. Do you feel this will prevent a cracked valve cover in a parking lot tip over? Or is it more designed to stop rash on the aluminum?


I’ve attached some images below showing how the X-Heads survived, from a driveway drop to racing on an HP2.  Through several years of testing and making mistakes, we now use a SuperToughTechnology Dupont Nylon that has a no break rating and is high heat and UV stabilized.  Our first products did crack but the newest generation of products do not. They are slightly ductile enabling the material to move in the process of absorbing the force of impact and prevent cracking.  Behind the outer shell is a thick thermoplastic rubber liner that rests against the valve cover, contributing to the dissipation of impact force.

The shot of the X-Head DOHC shows the effect in a driveway drop.  They are designed to cover 80% of the face of the head to protect, not only the bottom/front initial impact area in a drop, but also the upper part of the cylinder head.  Even in a stationary drop in a driveway, inertia can cause a bike to roll partially onto the face of the head before it settles down. In a more severe test of endurance, you can see that the surface of the X-Head on the HP2 is well worn from multiple drops but it remained intact saving the head cover.

MachineartManfallen DOHC
Sasaki HP2 s