The battle for supremacy between two-stroke and four-stroke quads is likely to rage on forever, except for outside factors that may end this age-old debate; it is very probable that upcoming legislation could end production of two-stroke engines, making it impossible to get a new two-stroke . So if you've ever considered getting a two-stroke quad, the clock is ticking.
The difference between a two-stroke and four-stroke lies in how often the spark plugs fire. While a four-stroke fires the plugs every other revolution of the cam, with each revolution of the camera, it fires once in a two-stroke. With everything being equal, a two-stroke is going to have twice as many combustions as a four-stroke, which causes it to produce energy. While this may make a two-stroke sound like an obvious choice, there are lots of drawbacks to the design and performance characteristics of two-stroke ATV engines.
The energy and heat made by a two-stroke require oil to be added to the gas to keep the engine properly compacted. Because oil is set in the combustion chamber, two-stroke motors smoke a whole lot, that is the main reason for the ban on them. One side effect of the power that two-stroke engines produce is that the end of the engine must be rebuilt somewhat frequently, depending on how hard the engine is pushed. Although the rebuild is not terribly expensive, it has to be carried out periodically to avoid rebuilding the whole engine.
For many riders, the constant maintenance would be well worth the performance they get from their two-stroke engine, but the availability of the power may be prohibitive for some riders, riding styles, and terrain. In order to tap into the power of a two-stroke engine, you have to keep the throttle near wide open to remaining in the powerband. Though some models are better than others, some inventory two strokes lack real power on the low or midrange. In the hands of an experienced rider, a two-stroke is an awesome machine, but in some instances, you may lose your power by producing a necessary upshift or slowing down without a hard downshift. However, their power makes two strokes the engine of choice for racers, particularly in racing disciplines that need frequent jumps and the quick acceleration out of turns, such as Motocross. If you plan on using your ATV to cultivate the garden, you are better with the more powerful version.
As for maintenance, most four-stroke quads require relatively little attention. Spark plugs and oil changes are necessary, but you do not have to rebuild the engine. However, many riders complain of the cost of rebuilding four-stroke motors when required, but a four-stroke engine should hold up longer than a two-stroke if it rides properly. If you keep a four-stroke in the rpm range all the time, you are asking for trouble. Although four-strokes don't have the attribute acceleration of a two-stroke engine, they have access to electricity through an rpm range, which eliminates the need. Access to electricity in the low and midrange allows for a much more riding experience, or the ability to dive into sand and come out the other side. Because a four-stroke has power on the low end, it has a time freeing itself while a two-stroke is doomed if it comes to a stop in the mud. Four strokes, oftentimes, have a higher top speed than two strokes but will take longer to reach their speed. Four strokes have improved a
lot, with many racing quads being propelled by four-stroke engines. However, the Honda 250R, a traditional two-stroke quad, is taking podium spots over ten years after it began production.
For the most part, two-stroke engines are better suited for light sport quads and four strokes, which produce most of their power on the low end, are more suited for thicker quads made for sand, rocks, and work applications. The debate between two-stroke and four-stroke engines is unlikely to end soon, but the production of 2 stroke engines may. If you prefer high speed, airborne, adrenaline heavy riding, and you don't mind spending some time; you might want to get your hand on a two-stroke quad while you can.