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

X-Heads and Heat


I have a 2012 BMW R1200RT.  I’m very interested in purchasing your X Head DOHC engine protection covers.  After your X Head engine protectors are installed, will my bike’s engine run hotter? Although your covers look to be very well designed, they also appear as though they would act like insulation and not let the engine cool properly.  What has your experience been and what can I expect?Tracy

Dear Tracy:

I’m asked this question often. While the X-Head covers the central area of the cam
cover, the whole top is open and the shape has openings at the front and back of the part that is open to the air. That is not as important as the fact that these “oil head” engines are both air and oil cooled and are thermodynamically robust.  The highest temperature concentration is around the exhaust port where it can go to over 330 degrees F at idle, but the finned cylinder where combustion occurs is totally exposed to cooling air all around.  Temperatures at the cam cover, where the cylinder guard is mounted, can range around 180F to 225F. It encloses the cam/valve train which is cooled by oil that is constantly circulated by the oil cooler up front.  The addition of a guard over a relatively cooler extremity is benign in the bigger scheme of how the engine handles heat.

On my own 2010 R1200GS with X-Head cylinder guards, whether I am riding the highway or going at a snail’s pace over a trail even during this summer’s 100 degree heat, the temperature gauge always remains at 4 bars, the middle position.  BMW’s own aluminum cylinder guards cover almost the same area which verifies that a cover  causes no ill effects.  Considering the design of your RT, however, the X-Heads look the best while being functionally effective.

Machineart Man