Motorcycle engine design and innovation has long surpassed that of the automotive industry, and industry observers agree that the big companies like Yamaha, Honda and Suzuki can muster considerable R&D prowess here, which can then be applied to their automobile engines.
Competitors are especially aware of this. Says former Oldsmobile chief engineer Ted Louckes: "That's where the leading edge of piston engine technology is today. It's not in automobiles; it's not in aircraft. It's in motorcycles."
The Goal: Better Combustion
When considering the advantages of a combustion chamber crammed with more than four valves-per-cylinder, the first inclination is to think, aha! Flow area! Five valves equals more flow area! True, to a degree, but that's only part of the Yamaha's design strength.
In the reigning days of the two-valvers, engine designers would control pinging by incorporating squish bands into the combustion chambers. By the 1960s, the four-valve heads of Cosworth and Honda racing engines were allowing narrow included valve angles and thus shallow combustion chambers. Put the spark plug in the center, and voila!, good combustion.
Yamaha looked beyond four valves to unlock even better combustion. In the early '80s (Yamaha had only been a serious producer of four-stroke engines for about ten years!) it experimented with a variety of head and valve configurations, even trying a seven-valve-per-cylinder (four intakes, three exhaust) design.
Finally, five valves per jug was found to be the right combination. This design gives the engine extra intake valve perimeter, which allows it to flow more air at low-to-medium valve lifts -- exactly where valves in most production automotive engines spend most of their operating time.
Honda of America Mfg., Inc., has combined plant and production engineering with advanced manufacturing techniques to become one of the leading engine producers in North America.
The million-square-foot plant manufactures 500,000 high technology engines and drive trains a year. Kinzer noted that the plant produces everything that makes a car "go and stop." He said that even Japan has no Honda facility comparable to the Anna plant. Its production, he reported, equals the total of seven similar Honda manufacturing units in Japan. At present production levels, a Civic or Accord engine is produced at the Anna plant every 27 seconds.
Honda's iron foundry operates three shifts per day. The ferrous casting and machining operations include the production of engine cylinder sleeves and brake discs and drums. Aluminum casting operations include high pressure casting of engine blocks and transmission and torque converter cases, low pressure casting of engine cylinder heads and gravity casting of pistons.
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Joe loves his motorcycle but he knows how to drive it safely. Learn more at his motorhead blog here: Motorcycle Batteries.
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