Controlling gases for the masses
how a motorcycle looks, feels, and sounds is important. How much planet cancer it kicks out the pipe as you ride matters just as much, which is why motorcycles are built around those regulations—from the combustion chamber’s shape to the size and placement of the exhaust. Standards differ around the world, and while Japanese and European benchmarks are a big factor in design, here in the US of A we conform to the mandates of the Environmental Protection Agency. The EPA has three basic classes pertaining to motorcycles—the largest being any engine more than 280cc. That means Honda’s 286cc CB300 follows the same rules as Harleydavidson’s 1,753cc Milwaukee-eight.
Exhaust emissions are measured in grams per kilometer of hydrocarbons, oxides of nitrogen and carbon monoxide, that get spit out the back of your machine as it rolls down the road. As of the 2010 models, that amount was nearly halved, from 1.4 to 0.8 grams. The test the EPA administers (and that manufacturers use to self-certify) is amazingly specific. Ambient temperature, when to shift between gears, and how much fuel is on board are all laid out, among myriad other items over dozens of pages. At the end of the day, the exhaust emission test is designed to determine emissions “while simulating an average trip in an urban area.”
These are the many reasons everyone from Aprilia to Zero spends so much time focusing on fumes. Because the stakes are ultimate. As one company’s head of engineering put it: “The downside of not passing is not selling. If there’s one thing you make sure you get right, it’s your regulatory compliance for noise and emissions.”