Catalytic Convertors
Motorcycles are regulated under section 202 of the Clean Air Act. It stipulates that the EPA needs to achieve equivalent emission reductions from both motorcycles and other vehicles as much as possible.
It’s not a well known fact, but according to the EPA many of today’s motorcycles produce more harmful emissions per mile than driving a car or even a large SUV. The current federal motorcycle emission standard for hydrocarbon emissions is about 90 times the hydrocarbon standard for today’s passenger cars. And the current California hydrocarbon standard is about 20 times the current federal passenger car limits. Harley-Davidson has had catalytic convertors (called “cats”) on all California and international (Euro III) models for a few years. In fact, 87% of all motorcycles sold in CA., during 2008 were equipped with catalytic converters.
However, Harley-Davidson has now put precious metals — catalytic convertors — in all 2010 models shipped. This is designed to help them meet the EPA specs and get them through 2011.
Cats have 3 main functions. Turn hydrocarbons into water and carbon dioxide; the nitrogen oxides into nitrogen and oxygen; and the carbon monoxide into carbon dioxide. To do so either one or a combination of three precious metals, platinum, palladium or rhodium is used. Conventional automobile cats are made from ceramics, but motorcycles use converters made from nickel and other metals that can better withstand vibrations. The weight of the devices and the high price of the metals has previously limited them to larger and more expensive motorcycles. However, a company in Japan (F.C.C. Co.), whose leading share holder is Honda has devised a catalytic converter made from paper and they hope to commercialize the product next year at a price point that enables them even on scooters. See HERE (in Japanese – .pdf).
We all know that modifying or customizing your ride is an integral part of owning one, but removing cats for performance purposes may no longer be an option. Many States prohibit exhaust modifications that increase emissions although they don’t have specific laws about removing catalytic converters. There have been attempts to mandate motorcycle “safety” inspections, but they have failed as it’s seen as a vail attempt to monitor motorcycle owners and any modifications to the exhaust systems. In the auto world there are a number of “aft-cat” exhaust systems. I haven’t seen as much (for example slip-on’s) for motorcycles, but for cars its basically an aftermarket replacement for your car’s factory exhaust, “after” the catalytic converter. Bassani is a major player in this space.
I believe the H-D 2010’s went out with a four-wire O2 sensor which is sometimes referred to as a narrow band. They switched to a heated narrow band sensor on the 2010s, which is why there are extra wires. Previously you could do exhaust mods on your ride and not trip the check engine light or set off a trouble code. I’m curious if anyone has completed mods on a 2010 model or if they’ve had issues with tripping the check engine light? I imagine there are or will be new maps, but all of these variables makes it more difficult and expensive to obtain high-quality performance exhaust tuning.
More information on motorcycle hydrocarbon etc., at: EPA (.pdf).
Photo courtesy of EPA and of BHLJ (Beihai Huihuang Langjie).
Northwest Harley Blog 