California Motor Vehicle Pollution Laws

August 5, 2007

In California, motor vehicle air pollution laws are in the California Code of Regulations (CCR).  It says any street motorcycle with a 49cc or under engine is exempt from California Exhaust Emission Standards.


13 CCR § 1958 Exhaust Emissions – Motorcycles

Cal. Admin. Code tit. 13, § 1958

Barclays Official California Code of Regulations Currentness

Title 13. Motor Vehicles

Division 3. Air Resources Board

Chapter 1. Motor Vehicle Pollution Control Devices

Article 2. Approval of Motor Vehicle Pollution Control Devices (New Vehicles) (Refs & Annos)
§ 1958. Exhaust Emission Standards and Test Procedures – Motorcycles and Motorcycle Engines Manufactured on or After January 1, 1978.

(a) This section shall be applicable to motorcycles, motorcycle engines, and the manufacturers of either motorcycles or motorcycle engines produced on or after January 1, 1978. Motorcycles and motorcycle engines are excluded from the requirements of this section if:

(1) The engine displacement is less than 50 cubic centimeters, or

(2) An 80 kilogram (176 pound) driver cannot

(A) start from a dead stop using only the engine, or

(B) exceed a maximum speed of 40 kilometers per hour (24.9 miles per hour) on a level paved surface.

(b) Exhaust emissions from new street-use motorcycles and motorcycle engines, subject to registration and sold and registered in this state, shall not exceed:

Table of Standards

  Engine Exhaust Emission Standards (g/km)  
Model-Year Displacement Hydrocarbon (HC) Carbon
  (in cubic centimeters) + Oxides of Nitrogen (NOx) Monoxide
================ =================== ============================ ========
1978 through 1979 50 to less than 170 5.0 (HC only) 17
  170 to less than 750 5.0+0.0155(D-170)  (HC only) 17
  750 or greater 14 (HC only) 17
1980 through 1981 All (50 cc or larger) 5.0 (HC only) 17
1982 and later 50 cc to 279 cc 1.0 (HC only) 12
1982 – 2/28/1985 280cc or greater 2.5 (HC only) 12
3/1/1985 – 1987 280cc or greater 1.4 (HC only), as a corp. avg. 12
1988 through 2003 280cc to 699cc 1.0 (HC only), as a corp. avg. 12
1988 through 2003 700cc or greater 1.4 (HC only), as a corp. avg. 12
2004 through 2007 280cc or greater 1.4 (HC+NOx), as a corp avg 12
2008 and later 280cc or greater 0.8 (HC+NOx), as a corp avg 12

Find out more about the California Motor Vehicle Pollution Laws »

United States Motor Vehicle Pollution Laws

August 5, 2007

In the US, the Environmental Protection Agency (EPA), Office of Transportation and Air Quality (OTAQ), has limits for motor vehicle emissions. There are exhaust emissions limits and there are evaporative emissions limits. Below is a excerpt from the EPA Regulatory Announcement of Dec 2003:

EPA Finalizes Emission Standards for New Highway Motorcycles – December 2003

The U.S. Environmental Protection Agency (EPA) is adopting more stringent emission standards for new highway motorcycles. Under the current standards, which are over 20 years old, today’s motorcycles produce more harmful emissions per mile than a car or even a large sport utility vehicle (SUV). These new standards will reduce the combined hydrocarbon and nitrogen oxide emissions in the exhaust by 50 percent as well as the harmful health effects of mobile source air toxics.

Final Rule Highlights

EPA has been working to reduce emissions from motor vehicles for over thirty years, including emissions standards for highway motorcycles that we adopted in 1978. In this final rule, EPA is adopting new emission standards for exhaust and evaporative emissions from highway motorcycles. The standards are based on comparable requirements adopted in California. The final rule extends the California requirements nationwide two years after they initially take effect in California. In addition to updating exhaust emission standards for currently regulated motorcycles, the new emission standards will include previously unregulated motorcycles with engines of less than 50 cubic centimeters displacement (scooters and mopeds). We are also adopting new evaporative emission standards to control the loss of gasoline (described as “permeation”) through the walls of fuel hoses and fuel tanks. The permeation standards apply to all classes of highway motorcycles.

Before 2006 model year, Class 1 was Class 1b (50 to 169cc), Class 1a (under 50cc) was exempt. Because of the new EPA standards, most 49cc two-stroke motorcycles, scooters, and mopeds stopped being made after 2005. Tomos and only a scarce few others still make two-stroke street motorcycles, which must meet the same standards as four-stroke engines.  

Highway Motorcycle Exhaust Emission Standards

Engine Size Implementation HC HC+NOx CO
Class (cc) Date (g/km) (g/km) (g/km)
======== =========== ============ ======= ======= =======
Class 1 less than 170 2006 1.0 12.0
Class 2 170 to 279 2006 1.0 12.0
Class 3 280 and above 2006 1.4 12.0
Class 3 280 and above 2010 0.8 12.0

HC = hydrocarbons (unburned gasoline or oil), CO = carbon monoxide = poisonous odorless gas

NOx = nitrogen oxides (with water makes nitric acid, leads to acid rain)

Click here to see the real thing:

Consumer information from EPA about non compliant inexpensive gas scooters:

Click here for Frequently Asked Questions to the EPA about Motorcycle Emissions Laws:

Here is an exerpt from the above link:

Would new emission standards make it illegal to customize my motorcycle?

Many motorcycle owners personalize their motorcycles. Indeed, this is one of the joys of owning a motorcycle, and owners take their freedom to customize motorcycles very seriously. We are not changing existing provisions of section 203(a) of the Clean Air Act, as established in 1977, which states that it is illegal “for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title…after such sale and delivery to the ultimate purchaser…”. In other words, owners of motor vehicles cannot legally make modifications that cause the emissions to exceed the applicable emissions standards, and they cannot remove or disable emission control devices installed by the manufacturer.

We use the term “tampering” to refer specifically to actions that are illegal under section 203 of the Clean Air Act; the term, and the prohibition, do not apply generally to the wide range of things that a motorcycle enthusiast can do to legally personalize their vehicle, only to actions that cause the emissions to exceed the standards. The new emissions standards do not change this “tampering” prohibition. In fact, it is not within EPA’s ability or discretion to change this statutory prohibition, which Congress put in place more than 20 years ago. Owners are still free generally to customize their motorcycles in any way, as long as they do not disable emission controls or cause the motorcycle to exceed the emission standards.

Highway Motorcycle Evaporative Emission Standards

Other emissions can come from the crankcase on a four-stroke engine, a result of blow-by past the rings, and from fuel that escapes into the air through permeation and evaporation, on all combustion engines.

 More to follow…


Tomos EPA Certification Labels

August 1, 2007

Vehicle Emission Control Information labels are required on all 49cc 2006-on US models.

More discussion to follow…

Motorcycle Noise Emission Control Information labels have been required since the early 1980’s.

Besides exhaust emissions and permeation (evaporative) emissions, there are also noise emissions limits. Noise limits have been in effect since the 1980’s. Since then it has been illegal to change the exhaust to a louder one, even though most motorcycle owners do it anyway.

Above left, 2009 Tomos LX Emission Label says 1.4 HC+NOx g/km, Engine Family: 9TOMCO.04A79

Above left, 2010 Tomos (all 6 models) Emission Label says 1.4 HC+NOx g/km, Engine Family: 8TOMCO.04A79

Above right, 2010 Tomos Noise Label says 70dbA @5415rpm.

Above left, 2011 Tomos ST Emission Label says 1.0g/km HC, 12g/km CO, Engine Family: BTOMCO.04A79

Above left, 2012 Tomos Sprint & ST Emission Label says 1.0 g/km HC, 12 g/km CO, Engine Family: CTOMCO.04A79

Above right, 2012 Tomos Noise Label, 70dbA @5415rpm. It’s been the same for many years.


Trans Fuel
Year Make/Model Exhaust Emission Limits Engine Family Permeation Family Oil Octane
==== = =========== =================== ============ ============== ==== ====
2006 Tomos not required ATF-A 90
2007 Tomos not required ATF-A 90
2008 Tomos ST 1.0g/km HC, 12g/km CO 8TOMCO.04A79 not required ATF-A 90
2009 Lazer 1.0g/km HC, 12g/km CO not required
2009 Tomos LX 1.4g/km HC+Nox 9TOMCO.04A79 not required ATF-A 90
2009 Tomos Smate 1.4g/km HC+Nox not required ATF-A 90
2010 Tomos Smate 1.4g/km HC+Nox 8TOMCO.04A79 not required ATF-A 90
2011 Tomos ST 1.0g/km HC, 12g/km CO BTOMCO.04A79 BTOMPMETAL 10 10W30 87
2012 Tomos ST 1.0g/km HC, 12g/km CO CTOMCO.04A79 CTOMPMETAL 10 10W30 87