Japan Plans Toughest-Ever Motorcycle-Emissions Rule

Japan's Environmental Ministry is seeking comments on its proposal for what would probably be the toughest motorcycle-emission law in the world.

Although it does not regulate particulate emissions, the proposed rule calls for very tight limits on oxides of nitrogen and hydrocarbons emitted by new sold by 2007. Allowed nitrogen oxide emissions would drop from 0.51 grams per kilometer to 0.15 g/km, and allowable hydrocarbon emissions would be cut to 0.3-0.5 g/km from the presentpermitted level of 2.93 g/km under this rule. The current testing regimen, which measures emissions through more than a dozen operating modes, including idle, acceleration, steady speeds, and deceleration, would continue to be used.

Although the standard would only apply to motorcycles sold in Japan, if it goes into force and manufacturers can in fact meet it (as we expect they will), then asking motorcycle manufacturers to meet such standards in other markets is easier because they have already developed the technology, demonstrated that such standards can be met, and know the costs of meeting the requirements. However, such standards still raise the cost of new motorcycles, and there are always concerns that such limits can have a negative effect on performance and driveability. (Those concerns don't always prove to be founded. When the first round of U.S. emissions standard went into effect in 1978, it did virtually eliminate two-stroke street bikes, but the bikes that replaced them were faster and more reliable with engines that required much less maintenance.)

Motorcycles are believed to be a much larger contributor to the rather severe air-quality problem in Japan than they are in the U.S. or many other parts of the world. The engine types and motorcycle designs sold in Japan are often different in other markets. In Japan, motorcycles are blamed for about 20% of the hydrocarbons in the air. The Ministry is curretly seeking to make major reductions in visible smog, blamed for an increase in respiratory diseases in that country.

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