In this article, we won’t talk about when to change your engine oil. If you google it, it will show 35,80,00,000 results within 0.55 seconds. Instead we will talk about what types of engine oil are out there and why you should use a specific motorcycle oil.
What does motorcycle oil do?
Engine oil wears many hats. Let us briefly look at those.
- The most basic one being, preventing engine wear and tear, by acting as a lubricant between moving parts.
- Second, it acts as an engine coolant and also as a cleaner. It cleans out all the surfaces it comes in contact with.
- Third, it increases the efficiency of the engine. A cooler is engine works better, hope you get the point.
- Last but not the least, it elongates engine life. A well-maintained engine will last longer than an abused engine.
Why there is a specific engine oil for your bike?
Engine oil works on the principle of friction and viscosity of fluid. There is friction or the lack of friction between the piston and cylinder walls allows a smooth operation.
Viscosity is the measure of a fluid’s resistance to flow.
For e.g. the more viscous a liquid is, the thicker it will be and the less it will flow. That implies, if we use a highly viscous engine oil, it will be thick and it will resist the movement of pistons. Hence, power of engine will be compromised.
On the other side, if we use a less viscous liquid, it will flow freely out of the gap between piston and cylinder. Hence, whatever fluid sticks to the surface will be the only little lubricant the engine will have to work with.
Viscosity is temperature dependent.
When temperature is raised, molecules in a liquid are energised and hence, start to move faster. This reduces the cohesive effect (which holds the molecules together). Liquid starts to flow more freely. Hence, viscosity decreases.
As bike engines get hotter, engine oil starts to lose its viscosity to a point where it starts flowing out freely. During winters, the reverse happens. Engine oil becomes so thick that it is unable to flow between the narrow gap between crankshaft and bearings, until the engine has developed enough heat to thin it out. 90% of engine wear happens during such situations.
As their name suggests, multi-grade oils act as thinner oils in low temperature and thicker in high temperature.
Notice the “15W-50” written on it. W stands for winter. The number on rither side have some significance. The number 15 represents the lowest point of temperature which the oil will hold its viscosity. If you’re located in place where the outside temperature is lower than the grade, it won’t be viscous enough to provide sufficient lubrication when the engine is started or running.
Now, the number 40 which is located after the letter ‘W’ represents the suitability of the oil performance in higher temperatures. If the temperature exceeds the set temperature, the oil will start to thin and lose its viscosity. When this happens, the oil will start to break down and won’t provide sufficient lubrication to the engine.
In India, temperatures can be as high as 45 °C, So, you can choose your engine oil according to the chart above. I would definitely use SAE 40.