• The cylinder head is made of a high heat conductive, lightweight aluminium 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°, the two intake valves and the 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 steps to insure tightening stability.