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You, Your Moped, and the Environment

The question has come up on numerous occasions concerning the environmental impact of riding a moped. This concern may stem from the fact that 2-stroke mopeds are having a very difficult time passing modern emission standards. It could also stem from an effort to find another virtue of the moped as an alternative form of transportation. Whatever the reason, there is one fact that we must contend with: Two stroke engines are DIRTY.

So what does this mean? Should I not ride anymore? How much damage am I doing? The short answer to these questions is written in large friendly letters: Don't Panic. The relatively small number of mopeds on the road compared to everything else pretty much negates any significant effect on the environment. Also, though your exhaust is EXTREMELY dirty, you still produce very little of it. When emission tests are done, they do not take into account over-all volume. Are you part of the problem? Yes. Are you THE problem? No!

So what can you do? Well, now it's time for the long answer.

What Are Emissions?

The primary components of gasoline engine exhaust are:

  • Water Vapor (H2O),
  • Carbon Dioxide (CO2)
  • Carbon Monoxide (CO)
  • Hydrocarbons (HOC), and
  • Nitrous Oxides (NOx)

All engines will produce these in varying amounts, and reducing the amounts of some of these compounds is the goal of emission controls on a modern automobile engine.

Why Are Two Strokes So Dirty?

There are a number of contributing factors to the increased emissions produced by two stroke engines:

  1. Air cooling -- Air cooled engines require looser tolerances between cylinder and piston in order to compensate for a wide range of operating temperatures.
  2. Oil is mixed with fuel -- This results in the burning of oil and therefore contributes to the overall emissions
  3. Fuel enters cylinder while exhaust is open -- This allows unburnt fuel to dump out the exhaust

What Can I Do?

There are several simple things you can do to reduce your moped's impact on the environment.

Maintain it

The first thing you can and should do is have your engine in proper working order. Are you running a huge jet to make up for leaking seals? Is your carburetor leaking everywhere? Is a clogged air filter causing you to four stroke? Is your exhaust pipe clogged? Are your wheel bearings good? Are your tires properly inflated? Fix these things first. Not only will you pollute less, your bike will perform better and you will enjoy riding it much more.

Buy better oil

The next thing to do is buy good two stroke oil. The better oils burn cleaner and leave less ash. This can result in slightly better performance and will result in less time spent cleaning out your exhaust. You can also purchase Castor based oil which will essentially be carbon neutral. Although Castor oils work very well, it should be mentioned that carbon deposits left by these oils can be extremely difficult to clean. If you go the castor-based route, make sure you're running clean already, mix it carefully, and do so at your own risk.

Get an expansion chamber

Last of all, try running an expansion chamber exhaust. These work by preventing a significant amount of the air fuel mixture from leaving unburnt through your exhaust port. Not only is this a good performance upgrade, but it should also help reduce the amount of hydrocarbon emissions from your bike.

Living Green With Mopeds!

If you are trying to leave this planet a little nicer than you found it but still want to hang on to your moped, consider these things:

  1. Your moped has already been made, and the creation of a new vehicle will result in significant pollution to air, water, and soil.
  2. Your moped has an extremely low carbon footprint. Gasoline has a fixed amount of carbon in it that will be released by combustion no matter how it's burnt. Seeing as how you burn so precious little, you are way ahead of the curve on this one.
  3. Your moped uses fewer resources: Less fuel, no lead battery (in most cases), tiny replacement parts.
  4. Less wear on roads.
  5. Easy to park. Yeah it's a stretch, but it does make going downtown to buy locally a lot easier. You're also not idling around the block four times looking for a parking spot.


Q: Can I run Ethanol to reduce emissions?
A: Yes, but good luck finding a lubricant that is compatible with ethanol. Regular two stroke oil will break down and seize your engine.

Q: Does my moped pollute more than a Hummer?
A: This argument has been brought up before. Your moped does pollute more per gallon burnt, but over distance traveled you will release less carbon and you will likely pollute less over all.

Q: Can I make my moped diesel and run it on vegetable oil?
A: Yes, If you can find a small enough diesel engine, or build one from scratch. A gasoline engine is not suited to take the pressures exerted by diesel combustion.