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Discussion Document
On-Road Vehicle and Engine Emission Regulations

Updating Canada's Motorcycle Emission Standards to Align with New U.S. Rules

4. Summary of Major Changes in EPA's Final Rule on Motorcycle Emission Standards for 2006 and Later Model Years

On January 15, 2004, the U.S. EPA published a final rule to introduce more stringent emission standards for on-road motorcycles beginning in the 2006 model year12. The EPA's new emission standards are generally intended to align with those of the California Air Resources Board.

The present U.S. federal emission standards for on-road motorcycles have been in place since the 1980 model year. It is generally recognized that these standards have not kept pace with developments in emission control technology that has been driven primarily by the adoption of progressively stringent emission standards for light-duty vehicles (i.e., cars) and light-duty trucks. While many of today's motorcycles are designed to emit considerably less than allowed under current standards, maximum allowable levels for hydrocarbon exhaust emissions are about 90 times higher for motorcycles than for light vehicles. The EPA's new standards will require significant improvements in the emission performance of on-road motorcycles.

The EPA rule introduces some new important elements in both the application and structure of future U.S. motorcycle emissions standards which must be addressed in order to maintain alignment of the Canadian Regulations. The following subsections review the main elements of the new U.S. rule.

It is important to note that the summary of the U.S. final rule is for convenience of reference and has no legal force or effect. For all purposes of interpretation or application of the U.S. rule, readers should consult the official publication in the U.S. Federal Register.

4.1 Regulation of Small Displacement Motorcycles (less than 50 cc)

For the first time, the EPA's new emission rules will establish emission standards for on- road motorcycles having an engine displacement of less than 50 cubic centimeters (cc) beginning with the 2006 model year. Historically, these low displacement motorcycles have been excluded from the scope of both EPA and California on-road motorcycle emission regulations. Vehicles in this category consist mostly of mopeds and motor scooters and are often powered by two-stroke engines with a displacement of 49 cc.

The application of emission standards to vehicles with displacement under 50 cc will result in a new "Class 1A" (under 50cc) with a useful life of 5.0 years or 6,000 km, whichever comes first. The previous Class I motorcycles (i.e., 50-169 cc) is renamed "Class 1B" and retains the same useful life of 5.0 years or 12,000 km.

In addition to the above, motorcycles that "cannot start from a dead stop using only the engine" will no longer be excluded from having to comply with emission standards for on-road motorcycles. However, pursuant to the definition of "motor vehicle" under 40 CFR13 85.1703, any motorcycle that cannot exceed a maximum speed of 40 km/hr (25 miles per hour) over a paved level surface will continue to not be considered a "motor vehicle" and will continue to not be subject to the emission standards for on-road motorcycles. Generally, any "motorcycle-type" vehicle that is not considered to be an on-road vehicle would be deemed to be a "non-road recreational vehicle" and would be subject to a different set of emission standards.

4.2 Exhaust Emission Standards

As mentioned earlier, the new final rule for motorcycles will generally harmonize the U.S. EPA emission standards with those of the California Air Resources Board14. With this new alignment, beginning in the 2006 model year the U.S. EPA will require that new Class I and II motorcycles comply with the present California highway motorcycle standards, which have been in place since 1982. Class III highway motorcycles will be required to meet the California Tier I and Tier II standards on a two year delay implementation (2006 and 2010 model year respectively) compared to California. The additional timing allowed with EPA's rule is intended to ensure that manufacturers have adequate lead time to plan for the new standards and to have full product lines available for sale. Table 4 summarizes the new U.S. EPA highway motorcycle exhaust emission standards and implementation schedules.

Table 4: New US Federal On-Road Motorcycle Exhaust Emission Standards
Implementation Model YearMotorcycle ClassEngine Displacement (cc)HC (g/km)HC + NOx (g/km)CO (g/km)
2006 and laterI< 1701.0 12.0
2006 and laterII170-2791.0 12.0
2006 and laterI or II< 280 1.4*12.0
2006 -2009 (Tier 1)III280 +--1.412.0
2010 and later (Tier 2)III280 +--0.812.0

* Optional standard for Class I and II motorcycles participating in emissions averaging.

4.3 Evaporative Emission Standards

For the first time motorcycles will be required to meet standards aimed at controlling evaporative emissions. Beginning in the 2008 model year, fuel tanks and fuel hoses on on-road motorcycles will have to meet the permeation emission standard that correspond to those in place for off-road recreational vehicles and engines outlined in 40CFR1051.110. These standards limit fuel tank permeation to 1.5 g/m²/day based on the inside area of the tank and limit fuel hose permeation to 15 g/m²/day based on the inside area of the hose. It is anticipated that these standards will result in an 85% reduction in permeation emissions from plastic fuel tanks and a 95% reduction in permeation emissions from fuel hoses.

4.4 Crankcase Emission Standards

The U.S. EPA's final rule maintains the existing prohibition on the discharge of crankcase emissions.

4.5 Compliance-Related Flexibilities

4.5.1 Optional Corporate Emissions Averaging

For the first time for motorcycles, the U.S. EPA rules introduce the option for companies to meet certain emission standards on a corporate fleet average basis. Companies can opt to certify some motorcycles at specified emission levels (known as the Family Emission Limit or "FEL") above the prescribed emission standard and certify other motorcycles to an FEL below the standard, provided that the calculated sales-weighted average emissions level of the company's new motorcycle fleet of a given model year does not exceed the applicable emission standard. The formula used for calculating a company's average emission level for a given model year is:

Average Emission Level = [∑i(FEL)i × (UL)i × (Production)i ]

[∑i(Production)i × (UL)i]


FELi = the family emission limit to which the engine family is certified
ULi = the useful life of the engine family
Productioni = the number of vehicles in the engine family

The new EPA rules allow a company to use emissions averaging as the basis for demonstrating compliance with the Tier 1 and Tier 2 "HC + NOx" emission standards for Class III motorcycles, with a maximum allowable FEL of 5.0 g/km for the 2006-2009 model years and 2.5 g/km for 2010 and beyond. Companies that certify Class I and Class II motorcycles to the optional HC+NOx emission standard can establish a separate averaging program for those classes with a maximum allowable FEL of 5.0 g/km for the 2006 model year and beyond. Emission credits15 generated by a company's Class III fleet of a model year may be used to offset a deficit in its Class I & II fleet in the same model year (credits are adjusted to account for different useful life).

Similarly, the EPA rules allow companies to use an emissions averaging program to meet the permeation emission standard for non-metal fuel tanks only.

4.5.2 Provisions for Banking Early Emission Credits

In general, the EPA's emission averaging provisions for motorcycles do not allow companies to bank emissions credits generated in a model year for use in later model years. However, companies can bank emission credits associated with the early introduction of Class III motorcycles certified with emission levels below the Tier 2 standards (i.e., in the 2003-2009 model years). The magnitude of the credits depends on the year the motorcycles are sold and the emission level of the motorcycles: the earlier the year of sale and the lower the emission level - the greater is the credit. Early emission credits earned by a company can be used beginning in the 2010 model year to assist the company in meeting the mandatory Tier 2 standards.

Unlike EPA's averaging provisions for light-duty vehicles and light-duty trucks, the averaging provisions for on-road motorcycles do not contain provisions for trading emission credits between companies. Also, there are no provisions to carry forward an emission deficit to be offset in a subsequent model year.

4.5.3 Provisions for Small-Volume Manufacturers

The U.S. rules provide new compliance flexibilities for "small-volume manufacturers"16, companies with fewer than 500 employees worldwide and fewer than 3,000 U.S. motorcycles sales per year. Small-volume manufacturers are required to comply with the Tier 1 standards for Class III motorcycles beginning in the 2008 model year, two years later than for larger companies. In addition, small-volume manufacturers are not required to comply with the Tier 2 standards for Class III motorcycles17.

4.5.4 Option to Use Engine Certified to Non-Road Emission Standards

The U.S. EPA has set out provisions to permit on-road motorcycles to use under 50 cc displacement engines that are certified for off-road use. These engines are certified for use in off-road motorcycles, snowmobiles, and all-terrain vehicles, or certified as off-road small spark-ignition engines at or below 19 kilowatts for use in lawnmowers, snow blowers, chainsaws, etc. The conditions for an off-road engine being used in an on-road motorcycle are:

  1. the engine must be produced under a valid certificate of conformity for Small Spark- Ignition Class II engines or Recreational Vehicles and Engines; 40 CFR Part 90 and Part 1051 respectively;
  2. the certified engine must not be changed in such a way that it could reasonably expect to increase exhaust emissions;
  3. an emissions label must be affixed to the engine as per the requirements of 40 CFR Part 90 or 1051; and
  4. fewer than 50% of the engine family would be used in on-road motorcycles.

In addition, a permanent label must be attached as follows:

  1. if the manufacturer produces both the engine and motorcycle, to the engine, containing the statement: "THIS ENGINE WAS ADAPTED FOR HIGHWAY USE WITHOUT AFFECTING THE ENGINE'S EMISSION CONTROLS.''; or
  2. if the manufacturer produces only the motorcycle, to the motorcycle, containing the statement: "THIS MOTORCYCLE WAS PRODUCED WITH A NONROAD ENGINE FOR HIGHWAY USE WITHOUT AFFECTING THE ENGINE'S EMISSION CONTROLS.''.
4.5.5 Exemptions for Specified Limited Cases

The EPA final rule contains various provisions whereby the Administrator may issue temporary exemptions from the obligation to meet specific emission requirements for reasons of financial hardship or hardship due to unusual circumstances. Special volume-limited compliance exemptions include for a person manufacturing a motorcycle for individual use (max. 1 per individual per life time of the provisions) and for custom motorcycles used solely for display purposes (max. 24 per company per year).

4.6 Emission Test Procedures

The EPA's final rule does not make any changes to existing exhaust emission test procedures for on-road motorcycles with two exceptions:

  1. new exhaust emission test procedures are adopted for the newly regulated category of motorcycles with engines of less than 50cc displacement; and
  2. changes to test fuel specifications. In addition, new test procedures are established to measure evaporative emissions resulting from permeation losses.
4.6.1 Exhaust Emission Test Cycle

Emissions from Class I motorcycles are currently measured with the vehicle operated on a test cycle that is less severe than for larger motorcycles (i.e., Classes II and III). The test cycle for Class I motorcycles is essentially the traditional cycle used for Class II and III motorcycles and other light-duty vehicles, but with lower top speeds and reduced acceleration rates. The Class I cycle has a top speed of 58.7 km/hr (36.5 mph), whereas the Class II/III has a top speed of 91.2 km/hr (56.7 mph). In its final rule, the EPA specifies a modified version of the Class I driving cycle for motorcycles under 50cc and having a top speed of less than 36.5 mph by adjusting each speed point of the driving cycle by the ratio of the top speed of the motorcycle to 36.5 mph (the top speed of the existing Class I drive cycle). "Vehicle top speed'' is defined in the regulations as the highest sustainable speed on a flat paved surface with a rider weighing 80 kg (176 lbs). The modified cycle is intended to ensure that these motorcycles are tested within their operational limits. Any motorcycle under 50cc with a top speed at or greater than 36.5 mph is required to be tested using the existing and unmodified Class I driving cycle.

4.6.2 Test Fuels

Current specifications for gasoline used for emission certification and compliance testing allow a maximum sulphur content of 0.1% by weight (i.e., 1,000 parts per million). This limit was originally intended to be representative of commercial fuel generally available at retail outlets. However, in 1999 the EPA adopted regulations requiring the introduction of low-sulphur gasoline (30 ppm average, 80 ppm maximum) nationwide in the 2004-2006 timeframe. Given that low-sulphur fuel will be the existing fuel in the marketplace when the new motorcycle standards are scheduled to take effect, the new EPA rule amends the motorcycle test fuel specifications to set a maximum sulphur content of 80 ppm.

4.6.3 New Evaporative Emission Test Procedures

The EPA rule adopts emission limits to control evaporative emissions resulting from permeation of fuel through fuel tanks and hoses. The rule also established new test procedures to determine compliance with the permeation emission limits.

In general, the permeation rate from fuel tanks is measured by filling a fuel tank with a blend of 90-percent gasoline and 10-percent ethanol (E10 fuel), sealing the tank and letting it soak at a temperature of 28 ± 2°C over a period of at least 2 weeks. The permeation loss is determined by measuring the difference in the weight of the fuel tank before and after the testing. Once the mass change is calculated, it is divided by the tank surface area and the number of days of soak to get the emission rate in units of g/m²/day.18

To determine a permeation emission deterioration factor, the EPA rule specifies three tests to ensure that the technology is durable and the measured emissions are representative of in-use permeation rates. The first durability test consists of filling the tank to 40-percent capacity with E10 fuel and rocking it for 1 million cycles at 15 cycles/min. The second test consists of pressure-vacuum testing containing 10,000 cycles from 0.5 to 2.0 psi at a rate of 60 seconds per cycle. The third durability test is intended to assess potential impacts of UV sunlight (0.2 µm-0.4 µm) on the durability of the surface treatment of the tank. The tank surface is exposed to UV light of at least 24 W/m² for 15 hours/day for 30 days. The durability factors are applied to permeation test results to determine the certification emission level throughout the full useful life of a motorcycle.

In the case of hoses, the permeation rate is generally measured at a temperature of 23 ± 2°C using SAE Recommended Practice J30 with E10 fuel. Like the fuel tank, the hose must also be preconditioned with a fuel soak to ensure that the permeation rate has stabilized.

4.6.4 Possibility of a Future World Harmonized Emission Test Cycle

In the preamble to its final rule, the EPA noted its participation in efforts under the auspices of the United Nations/Economic Commission for Europe (UN/ECE) to develop a global harmonized world motorcycle test cycle for emissions. The objective is to develop a scientifically supported test cycle that accurately represents the in-use driving characteristics of on-road motorcycles, and that could ultimately be integrated into the requirements of nations around the world.

As mentioned earlier, the U.S. final rule did not adopt any modifications to the current standard on-road motorcycle test cycle. Although a draft world test cycle has been developed, the EPA noted that some issues remain unresolved and it will likely be some time before a new cycle can be issued as a global technical regulation under the process established by a 1998 international agreement. The EPA expressed its intention to continue being involved in the process and its hope that a test cycle meeting the stated objectives can be agreed on by the international participants, including the United States, for future implementation.

12 Control of Emissions From Highway Motorcycles; Final Rule, U.S. Environmental Protection Agency, Federal Register, January 15, 2004

13 U.S. Code of Federal Regulations

14 With the exception of new EPA emission standards for motorcycles with an engine displacement of less than 50 cc.

15 Emission credits are generated when a company's fleet average emissions value in a model year is lower than the prescribed standard for the class; an emission deficit is incurred when a company's fleet average emissions value in a model year exceeds the prescribed standard for the class.

16 This would also include importers of motorcycles.

17 EPA indicated its intent to participate in a review planned by California in 2006 to evaluate progress in meeting the Tier 2 standards, which may include a reevaluation of whether the Tier 2 standards should be applied to small-volume manufacturers in the future.

18 Prior to this test for permeation emissions, the fuel tank is required to be preconditioned by allowing the tank to sit with fuel in it until the hydrocarbon permeation rate has stabilized - for 20 weeks at a temperature range of 28±5°C

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