See full version: If(typeof __ez_fad_position! undefined ) __ez_fad_position( div-gpt-ad-lawnmowerguru_com-box-2-0 ); 2 Stroke vs 4 Stroke Lawn Mowers: How Do They Compare
As the name suggests, with a 2 stroke engine each cycle only contains the 2 strokes we just mentioned – a compression stroke and a power stroke. The key point is that each cycle contains both of these strokes, and the piston only goes around the engine once per cycle.
The simple design of a 2 stroke lawn mower engine means that when things go wrong and a repair is needed, it’s almost always cheaper with a 2 stroke. It can get incredibly expensive to repair a 4 stroke engine and I’ve had more than one buddy that has just opted to buy a whole new mower rather than try to salvage an aging 4 stroke engine due to cost. more
Following on from the explanation of the basic functioning of a lawn mower engine above, there are some differences between how a 2 stroke works vs a 4 stroke.
Now we’ve got the technical stuff out the way, I’m going to run through the differences between the two from a user perspective. The stuff you’ll actually notice when using one to mow your lawn. here
The Exhaust system of a 2-Stroke engine is another reason for the loudness of it, the Exhaust Chamber plays vital role in functioning of a 2-stroke petrol engine. The Two-Stroke engine works on pressure wave theory and hence highly dependent on the exhaust gasses for the efficient fuelling. The importance of the Expansion Chamber cannot be overlooked in a 2-stroke engine, it must be designed in such a way that the exhaust gasses get enough space to expand. Overall volume of the gasses must also be calculated before designing the expansion chamber of a 2-stroke motorcycle. here
The first and foremost reason behind the high decibel sound produced from the 2-stroke petrol engine is the basic functioning of it. As compared to the 4-Stroke petrol engine which produces power in 4- cycles, the 2-stroke is characterized by producing power in two complete cycle of crankshaft. In simple terms a two-stroke engine fires at every cycle as compared to its counterpart, which fires at every alternate cycle. This means at a given RPM a 2-stroke engine fires twice than the 4-stroke engine, producing not only almost twice the power of a 4-stroke engine but also double the sound of a 4-stroke engine.
Another reason lies with the simple structure of the two-stroke petrol engine, the 2-stroke engine is known for its simple design hence it is devoid of complex engine parts as opposite to a 4-stroke petrol engine. In typical four-stroke petrol engine there is Valve Train, which includes Input and Exhaust Valves. On the other hand the 2-stroke engine comes devoid of any valve; the Exhaust Port of the engine is regulated by the piston against the dedicated Exhaust Valve given in a 4-stroke engine.
The Exhaust Valve present in a 4-stroke petrol engine provides better sound insulation and it acts as a muffler for the sound wave generated at the combustion chamber. Opposite to this the simple design of a 2-stroke engine has no exclusive valve train or valve system in it. The Exhaust Port present on the wall of the Block gets covered by the Piston and it gets opened and closed by virtue of the movement of the Piston itself. This whole setup is effective yet crude in form doesn’t work as good as a 4-stroke engine as far as sound muffling is concerned.
No wonder noise pollution was being taken as one of the major factors for banning the 2-Stroke petrol engines apart from the stringent emission norms. It is not that the manufacturers were unable to meet the emission norms related to the 2-Stroke technology; it was moreover easier/ feasible for them to move towards cleaner 4-Stroke technology. However, company like Honda is still trying to get the puissant 2-Stroke machine back with cleaner technology; it seems unlikely to see a 2- Stroke modern motorcycle with a Bazooka Silencer (pun intended). here
In order to operate the engine, four important processes must be performed: more
In a 2-stroke engine, the oil must be changed because this oil supports to cool the cylinder and piston by their proper lubrication. If you do not properly lubricate to cylinder and piston, the metals may melt and crush each other, metals can move past each other and deform permanently, and high friction can wear parts out and clog the engine. Therefore, it is advisable to keep changing the oil to keep the engine running properly. more
The 2-stroke engine is not environmental-friendly. The reason is that these engines have ports due to that waste heat leaves the cylinder and generates emissions. here
The two-stroke engine and four-stroke engine are different because they use different revolutions of the crankshaft and the different number of piston strokes to complete a power cycle. In a 2-stroke engine, all the four stages (intake, compression, power and exhaust) of a power cycle completes in just two strokes of the piston while, in a 4-stroke engine, all the four stages (intake, compression, power and exhaust) of a power cycle complete in four strokes of the piston.
Doug Henry came along riding a heavier and louder prototype (1997 YZM400F) and snuck away with a win in Las Vegas. From that point on, four strokes were on the map.
Again, the 2 stroke gets my vote… but (for me) this category doesn’t carry quite as much weight. [links]
However, when you get into the standard maintenance like cleaning the air filer and changing the oil, the two bikes are the same.