# Engine oil

> Engine oil lubricates, cools and cleans the engine's moving parts; on most motorcycles it also lubricates the clutch and gearbox.

- **Also known as:** Yağ, Motosiklet yağı, 10W-40, Engine oil, Motor oil
- **Turkish term:** Motor yağı
- **Category:** [Engine Oils](https://motorsikletparcasi.com/en/category/engine-oils)
- **Page:** https://motorsikletparcasi.com/en/glossary/engine-oil

Three things matter when choosing oil:

- **Viscosity (SAE):** e.g. 10W-40 – the figure before "W" describes cold flow and the second figure the thickness at operating temperature.
- **Performance class:** API (e.g. SL, SN) and, for motorcycles, [JASO](https://motorsikletparcasi.com/en/glossary/jaso-oil-standard) (MA, MA2, MB).
- **Base:** mineral, semi-synthetic or fully synthetic.

On wet-clutch motorcycles, car oils with friction modifiers can make the clutch slip; use a JASO MA/MA2 approved oil. The change interval depends on the model; on small engines it is typically 3,000–4,000 km and at least once a year. Change the [oil filter](https://motorsikletparcasi.com/en/glossary/oil-filter) at the interval in the manual too.

## Related terms

- [JASO (MA, MA2, MB)](https://motorsikletparcasi.com/en/glossary/jaso-oil-standard): JASO T903 is the Japanese standard that classifies four-stroke motorcycle oils by their compatibility with wet clutches: MA, MA1, MA2 and MB.
- [Oil filter](https://motorsikletparcasi.com/en/glossary/oil-filter): An oil filter traps metal particles and dirt in the engine oil so that clean oil circulates through the engine.
- [Clutch plates](https://motorsikletparcasi.com/en/glossary/clutch-plates): Clutch plates are the friction-lined discs in a wet multi-plate clutch that clamp against the steel plates to transmit engine power to the gearbox.

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- Source page: https://motorsikletparcasi.com/en/glossary/engine-oil
- Last updated: 2026-10-09
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