Although the model was designated 550, the actual capacity was 572.5 cc (34.94 cu in).[3] Honda developed a completely new, unusual design of engine to compete in the middleweight-sector with twin overhead camshafts acting on rockers, having screw-adjusters for clearance which actuated the sixteen valves (four per cylinder).
The engine featured a standard oil-cooler and a distinctive, unusual exhaust system, a first for Honda, with cross-over pipes directly in front of the engine linking cylinders one to four and a separate pair of pipes connecting cylinders two and three. The CV carburettors were of a new type using mixture-enriching internal fuel passages for cold-starts, with careful engineering of the inlet tracts to achieve smooth gasflow.[4]
The machine was noted for its use of inboard ventilated disc brakes, the discs themselves being contained within a "drum" type enclosure.[2] Front suspension was by oil-damped telescopic fork with air assistance and incorporating an anti-dive mechanism in the left fork leg.[2] Rear suspension was by Honda's own "Pro-Link" rising rate system, which allows the suspension forces to vary in accordance with rear wheel movement.[2] The machine was equipped with transistorised ignition and electrics were 12 volt.
