•  The cylinder head is made of a high heat conductive, lightweight aluminum alloy, which is quenched.

•  Compact, pentroof-type combustion chambers have been adopted. The spark plugs are mounted at the top of the combustion chambers to improve combustion efficiency.

•  The intake/exhaust port layout is a cross flow type, (the angle between two valves is 39°, there are two intake valves and two exhaust valves per cylinder) which improves air intake/exhaust efficiency.

•  The cylinder head bolts are plastic region tightening bolts to be tightened in five motions to insure tightening stability.