The battle for supremacy between two-strokes and four-strokes will likely rage forever, barring external factors that can end this age-old debate; it is very likely that upcoming legislation could end production of two-stroke engines, making it impossible to get a new two-stroke quad. So if you've ever thought about getting a two-stroke quad, the clock is ticking.
Mechanically, the difference between a two-stroke and a four-stroke is how often the spark plugs fire. A two-stroke fires once with each cam revolution, while a four-stroke only fires the plugs with every subsequent cam revolution. All things being equal, a two-stroke will have twice as much combustion as a four-stroke, causing the same size engine to produce much more power. While a two-stroke engine may sound like the obvious choice, there are several disadvantages to the design and performance characteristics of two-stroke ATV engines.
The extra power and heat produced by a two-stroke requires oil to be added to the gas to keep the engine properly lubricated. Due to the fact that oil is put into the combustion chamber, two-stroke engines smoke a lot, which is the reason for their impending ban. One of the side effects of the impressive power produced by two-stroke engines is that the top end of the engine has to be readjusted somewhat frequently depending on how hard the engine is pushed. Although rebuilding is not particularly expensive, it must be done regularly to avoid rebuilding the entire engine.
For many riders, the constant maintenance is worth the power they get from their two-stroke, but the availability of that power may be out of reach for some riders, riding styles and terrain. To harness the power of a two-stroke engine, you need to keep the throttle close to wide open to stay in the power band. While some models are better than others, some two-strokes lack real low- or mid-range performance. In the hands of an experienced rider, a two-stroke is an amazing machine, but in certain scenarios, you can lose all your power by having to upshift or decelerate without hard downshifting. However, their explosive power makes two-strokes the engine of choice for many racers, especially in racing disciplines that require frequent jumps and quick acceleration out of corners, such as motocross. When it comes to typical maintenance, most four-strokes require relatively little attention. Spark plugs and oil changes are always necessary, but you don't need to rebuild the engine regularly. However, many riders complain about the high cost of rebuilding four-strokes when necessary, but a four-stroke should last longer than a two-stroke if operated properly. If you keep the four-stroke high up in the rev range all the time, you're asking for trouble. Although the four-stroke doesn't have the characteristic acceleration of a two-stroke engine, it has access to power through a wider rpm range, eliminating the need to keep the throttle open all the time. Access to low- and mid-range power allows for a much calmer driving experience or the ability to dive into deep mud and come out the other side. Since the four-stroke has low-end power, it has a much easier time freeing itself from deep mud, while the two-stroke is usually doomed if it stalls in the mud. Four strokes have a higher top speed than two strokes in many cases, but it will take much longer to reach top speed. Four-strokes have improved a lot over the years, with some of the many dominant racing quads being powered by four-stroke engines. However, the Honda 250R, a classic two-stroke four-wheeler, is still on the podium ten years after the start of production.
Two-strokes are generally better suited for light sport ATVs, and four-strokes that produce most of their power at the bottom end are better suited for heavier ATVs built for mud, rock, and work applications. The debate between two-stroke and four-stroke engines probably won't end anytime soon, but the production of two-stroke engines will. If you prefer high-speed, airy, adrenaline-pumping riding and don't mind spending some time turning the key, you might want to get your hands on a two-stroke quad while you still can.
You must be logged in to post a comment.