Small, lightweight design is essential for hand-held and portable equipment. Honda's Mini 4-Stroke uniblock construction intergrates the cylinder, head, and upper crankcase into one piece. Its innovative OHV format uses a single cam to actuate both intake and exhaust valves, and its durable nylon cam gear and ultra-compact fuel tank further lighten the engine for the easiest possible handling and carrying.

An OHV crossflow combustion chamber with the spark plug positioned close to the center helps ensure excellent combustion efficiency for high power, and a wide, smooth range of torque impossible in 2-stroke engines. A floatless rotery-valve carburetor helps realize full 4-stroke performance potential through the entire engine-speed range. Valve-related mechanisms have been made lightweight and strong to eliminate high-rpm shock loads and ensure optimum performance even during extended high-rev use.