Generally there are three types of engine oil: fully synthetic motor oil, semi-synthetic, and mineral oil. Different motorcycles require different types of engine oil. When you buy a brand new bike, it’s crucial to change oil at particular intervals, as specified in the service manual of your motorcycle.
If you purchase a used motorcycle, one of the first things you should do is change the engine oil immediately. It doesn’t matter whether the oil is fresh or not. The engine oil is your engine’s lifeblood.
Using the right oil for your bike helps make your rides smoother but also prolongs the life of your engine. You can cause damage by using the wrong engine oil.
Purpose of the engine oil
Motor oil plays a vital role in the functioning of the motorcycle. They include lubricating the moving parts, cleaning the key internal components to avoid accelerated wear and tear inside the engine. Each time you restart your bike and rev the engine, the engine oil is there to lubricate, clean, and protect the engine against ultra-high temperatures and cold starts.
Motor oil also acts as a coolant just like the engine coolant. The 
oil soaks up high temperatures inside the combustion chamber; this helps reduce the internal temperatures of the motor. Extreme heat interferes with the performance of the motor. A cooler engine is quieter, more fuel-efficient and smoother. Apart from prolonging the life of the engine, the right type of oil also saves you money on future maintenance costs.
When to change the motor oil
How often you change the motorcycle engine oil will depend on the type of oil used during the previous oil change. If you don’t use your bike often, the engine oil should be changed at least twice a year.
If you’re using the simplest and cheapest form of motor oil, mineral-based motor oil, the oil should be changed after every 2,000 miles.
It’s a good idea to change the oils after 5,000 or 6,000 miles if you’re using semi-synthetic motor oil.
Fully synthetic oil is more expensive and lasts longer. Thus you don’t need to change them often. The general rule is to change the oil after 7,000 to 10,000 miles.
Consult your manual to check the best oil for your motorcycle.