Find Out Which Engine Type Is Best Before Choosing an ATV

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2 Stroke ATV vs 4 Stroke ATV - What's the Difference?. (Richard Gerstner/Getty Images)

If you've been around ATVs, dirt bikes, or other small performance engines for any length of time, you're probably familiar with the age-old debate between 2 stroke and 4 stroke engines.

What you may not be familiar with is that the many facets of this debate are moot points.

Mechanical Differences Between 2 Stroke and 4 Stroke Engines

The biggest difference is the number of times the cylinder fires during a stroke.

A "stroke" comprises Intake, Compression, Combustion, and Exhaust. A 2 stroke engine will do this by moving the piston up and down 1 time, a 4 stroke engine will take 2 times.

In other words, a 2 stroke engine has a "power" cycle every time the piston moves up and down once, and a 4 stroke engine moves up and down twice to make power.

As you can imagine, you get more bang for the buck with a 2 stroke because you get more power with the same size cylinder.

    Misconceptions About the Difference in 2 Stroke vs 4 Stroke Engines

    There are a few common myths people use when comparing 2 and 4 stroke engines.

    The most common misconception is that 2 strokes have to have pre-mix (mixing gas with oil). This is only a matter of simplicity. Take a look at Caterpillars; they have huge oil sumps, they have oil pressure AND they are 2 stroke engines.

    Valves at the top of the cylinder head in 4 stroke vs reeds in cylinder walls on a 2 stroke is also a misnomer.

    Cruise ships have turbo diesel 2 strokes with poppet valves.

      Emissions and Maintenance

      People will also try to tell you that 2 stroke engines produce more emissions than 4 strokes. In general, this is true. But there have been huge advances in technology that has made 2 strokes able to run as clean as 4 strokes.

      Surrich/Orbital 2 stroke design on Mercury outboards is a good example.

      Maintenance is more frequent on 2 strokes because they fire more and run hotter. You can expect to re-do the heads every few seasons. Fortunately, 2 strokes are much simpler and therefore easier to work on.

        The Bottom Line: Power!

        So, what's the difference? About the only difference between 2 stroke engines and 4 stroke engines, besides the number of times they fire in a cycle, is the amount of power they can make given that everything else is equal. Because the 2 stroke fires more often than a 4 stroke (twice as much as a 4 stroke), it naturally results in more power.

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          Your Citation
          Finley, Matt. "Find Out Which Engine Type Is Best Before Choosing an ATV." ThoughtCo, Mar. 27, 2017, Finley, Matt. (2017, March 27). Find Out Which Engine Type Is Best Before Choosing an ATV. Retrieved from Finley, Matt. "Find Out Which Engine Type Is Best Before Choosing an ATV." ThoughtCo. (accessed November 21, 2017).