The grade is not the specification

The best motorcycle engine oil for 2026

Motorcycle oil is sold on a viscosity grade — 10W-40 and the rest — and that is not the figure that decides whether it belongs in a given engine. The grade describes how the oil flows cold and hot. What decides compatibility is the specification printed next to it, and on a motorcycle that specification is usually a JASO one. The reason is structural rather than commercial: most motorcycles run a clutch that sits in the same oil as the engine, so the oil has to lubricate bearings and still let friction plates grip. A car oil with friction modifiers does the first job well and the second badly, and the result is a clutch that slips under load. JASO MA and MA2 exist to mark oils tested for that use, and a maker publishes which one an oil meets. MB exists for machines with a dry clutch or an automatic transmission and is not interchangeable with MA. Alongside that sits an API service classification, which describes the oil's protective properties and is published as a two-letter code. The third published line is the base: mineral, semi-synthetic or fully synthetic, which changes the drain interval a manufacturer specifies and the price by a factor of several. This site reports the grade, the specifications and the base as the maker publishes them, and points at the machine's own manual for which combination that machine requires — because the manual is where that answer lives, and no comparison page knows which engine is in front of it. We compare viscosity grade, published JASO and API specifications, base type, container sizes and published drain guidance.

These parts compared, figure by figure

1. 

   Liqui Moly Motorbike 4T 10W-40, 1 L

   A one-litre mineral 10W-40 four-stroke motorcycle oil published against API SN PLUS and JASO MA2, stated to suit wet clutches and tested with a catalytic converter.

   Specifications

   API SN PLUS | JASO MA2 (maker’s bullet)

   Oil type

   Mineral (maker’s bullet)

   Viscosity

   10W-40 (from the title)

   Wet clutch

   Stated excellent for wet clutches (maker’s bullet)

   Volume

   1 litre (from the title)

   Other stated properties

   Catalytic-converter tested, low oil consumption, ageing stability, high shear stability, engine cleanliness (maker’s bullet)

   Amazon reference

   B00N5ZP8HM (one reference across 6 Amazon marketplaces)

   EAN

   4100420030444

   • Publishes both classifications — API and JASO — which is the pair that decides a motorcycle oil
   • States the oil type plainly as mineral, where two rivals here leave it unstated
   • Mineral oil has shorter drain intervals than a synthetic

   Best for: Topping up, or changing the oil on a machine whose manual asks for JASO MA2 in 10W-40.

   ≈ €14

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2. 

   Castrol POWER1 4T 10W-40

   A one-litre HC-synthesis 10W-40 motorcycle oil published against API SN and JASO MA-2, with the maker stating explicitly that the printed date is manufacture and not expiry.

   Specifications

   API SN | JASO MA-2 (maker’s bullet)

   Oil type

   HC synthesis (maker’s bullet)

   Viscosity

   10W-40 (from the title)

   Protection

   Stated combined protection of engine, gearbox and oil-bath clutch (maker’s bullet)

   Shelf life

   The maker states the product has NO expiry date; the printed date is the manufacturing date (maker’s bullet)

   Packaging

   The maker states packaging may vary (maker’s bullet)

   Amazon reference

   B0C8148X2L (one reference across 6 Amazon marketplaces)

   EAN

   4008177183201

   • Publishes both classifications, and names the oil type as HC synthesis
   • Settles the date question outright, which is the most common worry about a can that has sat on a shelf
   • API SN rather than the SN PLUS published by one rival here

   Best for: A machine whose manual asks for JASO MA-2, and a garage shelf where cans sit for a year.

   ≈ £12 / €11

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3. 

   Motul 5100 4T 10W-40, 4 L

   A four-litre 10W-40 four-stroke motorcycle oil whose listing publishes no API category, no JASO grade and no oil type — its eight bullets are four brand sentences repeated.

   API category

   NOT published in this listing.

   JASO grade

   NOT published in this listing — and JASO is what decides a wet clutch.

   Oil type

   NOT published in this listing — mineral, HC synthesis or synthetic is not stated.

   Viscosity

   10W-40 (from the title)

   Volume

   4 litres (from the title)

   Listing bullets

   Eight, consisting of four brand sentences printed twice — about premium quality, market demands, international approvals and 150 years of lubricants.

   Amazon reference

   B00IKCY4ZC (one reference across 6 Amazon marketplaces)

   EAN

   0337465024709

   • A four-litre can, which is a full oil change rather than a top-up
   • From a lubricant maker with its own published technical data
   • Publishes no API category, no JASO grade and no oil type — the three things that let a motorcycle oil be matched to a manual

   Best for: A rider who already knows this product and is re-ordering it, or one prepared to read the maker’s own data sheet.

   ≈ $58 / £49 / €41

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4. 

   MANNOL 4-Takt Plus 10W-40

   A four-litre 10W-40 four-stroke oil published against JASO MA/MA2 and API SL, with wear and scuffing protection stated to come from esters, for engines with or without an oil-bath clutch.

   Specifications

   JASO MA/MA2 and API SL (maker’s bullet)

   Viscosity

   SAE 10W-40 (maker’s bullet)

   Additive

   Wear and scuffing protection stated to come from esters (maker’s bullet)

   Clutch

   Stated suitable for modern four-stroke engines with AND without an oil-bath clutch (maker’s bullet)

   Volume

   4 litres (from the title)

   Oil type

   Not published as mineral, HC or synthetic — the ester content is named instead.

   Amazon reference

   B00G32H85E (one reference across 6 Amazon marketplaces)

   EAN

   4036021401669

   • Both classifications published, on a four-litre can — a full change with a matchable specification
   • Names the additive chemistry, which almost nothing on this shelf does
   • API SL is an older category than the SN and SN PLUS published by two rivals here

   Best for: A full oil change where the manual asks for JASO MA or MA2 in 10W-40.

   ≈ €24

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5. 

   Liqui Moly Motorbike 4T 10W-40, 4 L

   The four-litre can of the same mineral 10W-40 motorcycle oil published against API SN PLUS and JASO MA2, sized for a full oil change rather than a top-up.

   Specifications

   API SN PLUS | JASO MA2 (maker’s bullet)

   Oil type

   Mineral (maker’s bullet)

   Viscosity

   10W-40 (from the title)

   Volume

   4 litres (from the title)

   Wet clutch

   Stated excellent for wet clutches (maker’s bullet)

   Relation to the 1 L can

   Same specifications, same oil type, different reference and different volume.

   Amazon reference

   B00N5ZPB8S (one reference across 6 Amazon marketplaces)

   EAN

   4100420030468

   • The highest API category published in this family — SN PLUS
   • A full-change volume with a fully published specification
   • Mineral, so drain intervals are shorter than a synthetic

   Best for: A full oil change on a machine specified for JASO MA2, with the matching one-litre can for top-ups.

   ≈ £44 / €38

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