Difference between a 2 and 4 stoke engine?

12 Answers

  • Evgeni
    Lv 7
    1 decade ago
    Best Answer

    The two-stroke internal combustion engine differs from the more common four-stroke engine by completing the same four processes (intake, compression, combustion, exhaust) in only two strokes of the piston rather than four. This is accomplished by using the beginning of the compression stroke and the end of the combustion stroke to perform the intake and exhaust functions. This allows a power stroke for every revolution of the crank, instead of every second revolution as in a four-stroke engine. For this reason, two-stroke engines provide high specific power, so they are valued for use in portable, lightweight applications such as chainsaws as well as large-scale industrial applications like locomotives.



  • 1 decade ago

    given the same size engine, the 2-stroke will be more powerful

    I've never owned a 2-stroke engine, but from what I've heard and read...

    2-strokes are smaller and lighter than 4-strokes

    they're more simple so repairs are less complicated

    on the other hand...

    4-strokes are much cleaner

    more fuel efficient

    don't need to mix gas

    less temperamental (don't require as much fiddling and adjusting as 2-strokes)

    also, 4-strokes tend to have a much flatter torque curve, while 2-strokes work well only within a pretty tight RPM range

  • Anonymous
    1 decade ago

    The other answers (detailed answers) were correct in-so-much as they expounded on the fact that in a 2-stroke, the cylinders fire at the top of every revolution and they need to run mixed gas (oil & fuel), however they are WRONG in asserting that they deliver more power. While they will provide higher RPM and deliver RPM (Revolutions Per Minute) faster, the 4-stroke engine is much more POWERFUL. RPM does NOT equal power. Look at diesel engines...they're 4-stroke, run much LOWER RPM than gasoline engines but deliver much more power. In a 4-stroke engine, the third stroke is known as the POWER stroke, it's "Intake, Compression, POWER, Exhaust". "Combustion" is not a stroke...it's what happens at the beginning of the power stroke..

  • 4 years ago

    A 2 stroke will have a very flat head straight across the fins, a 4 stroke will have 2 round plugs visible from the sides for the cams.

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  • 1 decade ago

    2-cycle bikes have superior output for a given displacement size. They sound better, they are easier to start and re-start, cheaper and easier to repair and maintain... cheaper to initially purchace.. usually handle better

    4-cycle engines are great for dual sport or road legal bikes.. they offer superior fuel economy and the power is usually easier to use...

  • 1 decade ago

    a 2 stroke engine uses fuel transfer ports in the barrel to feed the engine,a 4 stroke uses valves in the head via a chaine driven camshaft....a 2 stroke strokes twice [induction and compression an one stroke and ignition and exsaust in another stroke.....a 4stroke ...suck squese,bang blow.....

  • Anonymous
    1 decade ago

    the engine in a two stroke fires everytime the pistons reach the top, the engine in a four stroke fires every OTHER time the pistons reach the top. thus the two stroke is twice as powerful as a four stroke is.

    edit damnit someone already answered with the pics... ok that's what you get for making your answer complicated, i just skipped over it...

    Source(s): here's a graphic cutaway of each to help you better understand the real diffrence. 2 stroke engine - http://en.wikipedia.org/wiki/2_stroke 4 stroke engine - http://en.wikipedia.org/wiki/Four_stroke
  • Ken D
    Lv 4
    1 decade ago

    2 stroke you need part 2 stroke oil mixed with petrol, 4 stroke is petrol only.

  • 1 decade ago

    the only difference is your doing the stroking

  • 1 decade ago

    the noice? I think.

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