Imagine the scene. You've scored your dream job at last-designing new sportbikes at a big Japanese firm. It's your first day and you're in the deep end, working on a new flagship superbike.
After wedging the 250-horsepower engine into a neat, new, cast magnesium frame, attaching the world's first single-sided, carbon-fiber swingarm and finishing it off with a set of Kevlar bodywork, you're feeling pretty good. It's got more performance than an AMA superbike, and makes the Ducati 916 and the MV Agusta F4 look like a pair of junkyard dogs.
But hold on. The job's not done. Your supervisor pops his head in and hands you a thick wad of paper. The front page says "49CFR: Part 571" and each page is crammed with technical specs on everything from switch gears to headlights, license plate lamps to turn signals. Further down is a list of regulations from the EPA and the CARB. By the time you get done adding reflectors, turn signals, license plate holders and mirrors, your gorgeous megabike looks like it was made out of Play-Doh by a 3-year-old.
Then word comes back from the dyno department-the exhaust they've had to fit to keep the noise and emissions down is the size and complexity of a small nuclear plant. Your sleek titanium system now looks like someone let off a truck bomb in the plumbing department of Home Depot. Your amazing prototype design is shattered.
We're obviously oversimplifying for effect here, but the point remains. There is a whole set of things that the bike firms have no choice in fitting to their bikes if they want to sell them. In the U.S. there are the Code of Federal Regulations (CFR) rules, backed up with standards set by the National Highway Traffic Safety Administration (NHTSA) and the Society of Automotive Engineers (SAE), and the stiff environmental standards set by the Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). There are also various regulations at state level, which vary widely according to where you live.
Other countries have similar schemes-notably the European Union regulations covering European countries. Here's a summary of what the regs are, who sets them and what they mean for your bike.
"You punks and your loud pipes...
"You punks and your loud pipes are asking for it!"
Emissions
This is perhaps one of the toughest areas to comply with. There are two areas of concern-noise pollution and emissions of harmful exhaust gases. The first, noise, is pretty straightforward: The bike is ridden past a microphone at a set distance (100 feet) at a set rate of acceleration in second gear. If it's louder than 80 decibels, it fails the test. When the test first appeared in the 1980s, the limit was higher, at 86 decibels-proving old bikes really do sound better!
Manufacturers expend a load of effort in making exhaust systems that are quiet enough to pass the test, yet still produce good power. Devices like ECU-controlled butterfly valves (notably in Yamaha's R-series bikes and Suzuki's GSX-Rs) are set to close at low- and midrange rpm, making the exhaust quieter, then opening at full revs to give ultimate peak power.
Tactics like clever chain design, double-thickness engine covers and even foam rubber panels lining the inner fairing all help reduce mechanical noise emitted from the bike, and allow a bit more noise from the exhaust pipe-improving power.
The gas emissions from your bike's exhaust are another area controlled by the government. Gasoline engines produce a variety of ugly emissions, including carbon monoxide (CO), unburnt hydrocarbons (HC), nitrous oxides (NOx) and other poisonous organic chemicals. Untreated, these can cause smog in cities, and aggravate lung illnesses and even acid rain. Happily, a small catalytic converter can reduce all these pollutants to miniscule levels. The catalyst itself is a honeycomb cell of ceramic material coated in clever, rare metals like palladium, rhodium and platinum. When heated by the bike's exhaust gases, these catalysts convert all the nasties into carbon dioxide and water-much less dangerous stuff.
EPA rules have tightened up over the years, ratcheting down the amounts of HC, CO and NOx allowed. That means manufacturers have had to work harder-moving catalyzers closer to the engine so they heat up faster and begin working sooner on a trip. Some advanced engine management systems now use a lambda sensor (or oxygen sensor) in the exhaust so that the ECU can constantly re-tune the fuel mixture to reduce pollution and keep fuel consumption to a minimum.
Catalysts and sensors all add complexity, weight and cost to our bikes though. And since there are (relatively) very few motorcycles on the road, it's debatable how much impact they actually have on the environment-and how much difference the requirements actually make in the real world.