Motorcycle oil: mineral, semi-synthetic or fully synthetic

Oil type affects engine protection, clutch feel and how often you change it. Pricier isn't always better: what counts is what your bike's manufacturer specifies.

• Open the owner's manual: it gives the SAE viscosity grade and the API or JASO specification.
• For a wet clutch, which most bikes have, use oil rated JASO MA or MA2. Car oil marked energy conserving can cause clutch slip.
• Mineral suits simple, older engines under moderate load, but it breaks down faster and needs changing more often.
• Semi-synthetic is the compromise: steadier viscosity when hot at a moderate price, fine for daily riding.
• Fully synthetic holds its film better in heat and on cold starts, so it makes sense for high-output engines, track use and hard riding.
• Change oil and filter on the schedule in the manual, and at least once a year if you only do short rides.