Difference between 4-Stroke and 2-Stroke engine oils
We divide the motorcycle and scooter engines in two main categories; 4-stroke (4T) and 2-stroke (2T) engines. The difference between these two types is based on the number of times (strokes) the piston moves up and down during each cycle. Thus, in a 4-stroke engine, power is produced every four strokes of the piston, and logically, in a 2-stroke, power is produced every two strokes of the piston. Different type of engine oil is also needed because 2-stroke engines require the oil to be pre-mixed with the fuel and the mixture is burned during the combustion. This working principle requires, of course, different oil properties.
Most modern motorcycles and scooters nowadays contain a 4-stroke engine because of the fuel economy and environmentally friendliness. 2-Stroke engines are typically found in smaller applications such as lawn tools, go-karts, chainsaws, boat motors and dirt bikes. In general, a 2-stroke engine has less moving parts thus is both cheaper and lighter, and provides excellent power to weight ratio. On the other hand, a 4-stroke engine provides smooth and quiet operation and produces lower Hydrocarbon (HC) and Carbon Monoxide (CO) emissions.
Requirements of the lubrication System
Requirements of lubrication system for motorcycles can be very different, not only depending on the type of engine (2T or 4T) but also on the type of motorcycle and the way of using (city driving, high mileage, racing).
For example, during the cold season, scooters are used more often than motorcycles, so special oils must remain in critical condition due to operation at low temperatures. These oils must also minimize potential problems due to frequent engine start-up and shut down and to the stop & go conditions of urban driving.
If you have very high mileage, the engine oil must offer good protection together with very low oil consumption and a good fuel economy.
Racing motorcycles with very high specific power and extreme operating temperatures require oil that must resist to very high thermo-oxidative conditions (mostly fully-synthetic) and must provide a smooth gear shifting together with easy operation of the wet clutch.
Wet clutch versus dry clutch
Wet clutches have the clutch pack inside the crankcase, which allows the engine oil to coat the clutch components and keep things cooler and quieter. Wet clutches do make your engine oil dirty faster since all the dust that is created as the clutch wears stays inside the engine. Most automotive engine oils contain friction-modifying additives that are beneficial to a car or truck's engine, but not so much for motorcycles. This because these additives will interfere with the clutch's friction plates and cause the clutch to slip.
Dry clutches aren’t bathed in oil. That means less drag and more power going to the rear wheel as well as cleaner engine oil, but it also means less cooling for the clutch pack. Because of less drag on the engine, in a competition like the MotoGP, a dry clutch is used, for in racing every little advantage helps. The downside of a dry clutch is, however, that it wears out faster, and that the engine creates much more noise. It’s mainly because of the durability and the quietness, the vast majority of motorcycles have a wet clutch.
Synthetic and mineral engine oils
Compared to mineral oils, synthetic lubricants will ensure higher performance, in a wider range of temperatures, and better oxidation stability, which is translated in a longer drain interval. For example, for racing and competition motorcycles, where operative RPM (rotation per minute) and temperature are higher than normal motorcycles, synthetic oil is recommended.
Motorcycle engine oil specifications
Besides the type of oil, you also need to consider the specifications. The most important kind of specifications is from the Japanese Automotive Standard Organization (JASO). The JASO MA qualification, for example, indicates good performance with a wet clutch, while JASO MB has different friction performance. It is therefore not suitable with a wet clutch and is mostly recommended for scooters.
Eni I-Ride engine oils
Eni offers a complete range of high-performance lubricants for motorcycles and scooters; the Eni I-Ride range. This range is segmented in Racing, Street & Touring, Off-Road and Scooter, all with their unique properties and different viscosities. Racing engine oils, for example, have been created for optimal reliability and protection in extreme conditions during motorsports competitions. Meanwhile, Street & Touring oils are more suitable for long highway driving and urban traffic use.
For more information about which engine oil is suitable for your motorcycle, please advise the Eni Lube Finder, or contact us for more information.
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