The 2-Stroke Dope?

We’re big fans of Cecil Adams’ The Straight Dope, and we’re one of the few scooter-centric media outlets that thinks the ecological hype surrounding scooters is somewhat overstated, but we’re guessing Cecil’s recent “Give a Scooter, Pollute Her” column is somewhat misleading, along the same lines as Willamette Week’s “Polluter Scooters” story from August 2006.

What Cecil’s column doesn’t mention is that few scooters sold today are 2-strokes, and most 2-stroke scooters sold today are designed to conform to CARB and recent E.U. standards, which are, as we understand it, far more aggressive than national EPA standards. Sure, vintage 2-stroke scooters pollute. A lot. And modern 2-stroke scooters generally pollute more than modern 4-stroke scooters. But even a Genuine Stella, the only non-CARB-approved 2-stroke scooter sold in the U.S.(aside from quasi-legal Chinese imports)–even by Willamette Week’s numbers–pollutes far less than an out-of-tune worn out vintage scooter of similar design, and while it has a comparatively high PERCENTAGE of pollutants, it compares favorably when the QUANTITY of pollutants is measured against a higher-displacement vehicle that creates more exhaust.

Unlike the earlier WW story, Cecil’s numbers seem to be balanced for displacement, and support his case. He also generously explains how scooters are beneficial in other ways, but it still seems disingenuous to not mention that most scooters sold in the U.S. today feature 4-stroke engines, vapor recovery systems, and other emissions controls. Vespa claims that their scooters emit about 72% less emissions than an average car (and 78% less than an average SUV). Vespa’s numbers are usually inflated, and they’re not separating out the specific pollutants Cecil cites, but I find it hard to believe that a modern small-displacement one-cylinder 4-stroke engine releases a larger quantity of pollutants into the atmosphere than an SUV. BajajUSA (now ArgoUSA), who recently imported vintage-Vespa-styled Bajaj Chetaks with modern 4-stroke engines, reported amazingly low emissions and did break them down into specific pollutants.

Again, we agree that fuel savings (vs. operating cost) benefits and ecological impact arguments of scooters are often overstated, and we appreciate Cecil’s positive justifications for scooters. CARB and Euro requirements, as well as emissions tests from various scooters, are all easy to find online, but different units and different testing methods make them difficult to compare. Maybe Cecil’s right, butwe’re betting that scooter emissions, especially modern 4-stroke scooter emissions, aren’t nearly as bad as they’re made out to be by stories like this.

4 thoughts on “The 2-Stroke Dope?”

  1. Another thing to consider is that if cars are driven, on average, 100,000 miles in their lifetime, they only consume half of their net oil inputs as gas & oil. The other half (approx. 50 barrels) is consumed as plastics and energy in the manufacturing process.

    Any comparison of energy efficiency between cars and scooter which ignores half of the car’s inputs is, IMHO, patently dishonest.

  2. Cradle To Grave analysis would speak volumes. But I’ve never heard of anyone doing a proper analysis for cars or bikes. There would be too much interest in the outcome.

  3. Cecil’s story is quite accurate. As he said, it really depends what your goal is. If you are interested in reducing CO2, energy security, and global warming than scooters are the clear choice. If you are concerned about smog forming emissions regulated by the CARB and the EPA then scooters, even 4-strokes, are gross polluters compared to even SUV’s.

    My only issue with Cecil’s story is that he compares emission standards, (the amount of pollution a vehicle is allowed to emit) instead of actual measure emission. Data for actual emission is easily available, all one needs to do is go to CARB’s website and look at the certification data:

    Here you will find the actual emissions data submitted by manufacturers to CARB in order to certify that the vehicle meets emission regulations. This data is collected by running the vehicle through a uniform test and measuring the emissions.

    Some Scooter data:

    Vehicle ———————— HC ————- CO ————- NOx ————— Total
    Aprilia Scarabeo 100 —— 0.2 ————– 1.0 ————– ? ——————- 1.2
    Vespa LX 150 —————- 0.1 ————– 5.0 ————- ? ——————– 5.1
    SYM HD 125 —————– 0.9 ————– 1.0 ————– ? ——————- 1.9
    Genuine Buddy 150 ——– 0.4 ————– 7.0 ————– ? ——————- 7.4
    Genuine Rattler 110 ——– 0.9 ————– 7.0 ————– ? ——————- 7.9
    SYM HD 200 —————— 0.7 ————– 4.0 ————– ? —————— 4.7
    CARB Regulation ———– 1.0 ————– 12.0 ———— ? ——————- 13.0
    (Note: All numbers are grams per kilometer, scooters are not tested for NOx)

    As you can see actual, scooter emission vary wildly but all are much lower than what CARB allows. One can’t really stereotype 2-stroke vs 4-stroke either. While the Rattler 110 is a 2-stroke and is the most polluting on my list it is only 7% worse that the 4-stroke Buddy.

    Car and SUV data:
    Vehicle ———————— HC ————- CO ————- NOx ————— Total 2010 Toyota Prius ——— 0.031 ———- 0.025 ———– 0.002 ————- 0.058
    2009 Suburban 6.0L 4×4 0.026 ———- 0.559 ———– 0.012 ————- 0.597
    CARB Regulation ———- 0.056 ——— 2.600 ———— 0.043 ———— 2.699
    (Note: All numbers in grams / kilometer (converted from grams / mile))

    Again, vehicles vary widely but even the worst cars and SUV’s are well below the emission standard. However, even the best scooter emits 20x more pollution than a Prius and 2x more than a 4×4 Suburban.

    So again, it depends on what one is more concerned about. If one is more concerned about the air quality of their city than any car is better than a scooter. If one is more concerned about reducing the consumption of gasoline and other natural resources than a scooter is the better choice.

  4. Smog on one hand, global environmental devastation on the other. Smog is a local problem and it seems to be the only thing that nationwide regulations are concerned about. So this is all Los Angles’ fault? Screw them and bring back the RZ350. Let LA and other smog sensitive communities deal with local bans and let everyone else go about saving the planet and having fun.

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