AMSOIL guide
AMSOIL Motorcycle Oil Guide
AMSOIL builds three families of synthetic motorcycle oil: V-Twin for Harley-Davidson and other air-cooled push-rod engines, Metric for liquid-cooled Japanese and European four-strokes, and Dirt Bike for off-road four-strokes. All three carry the JASO MA/MA2 wet-clutch certification and use 100% synthetic base stocks. Pick the family by engine architecture, then pick the SAE viscosity from your owner's manual. For a model-specific match, use the motorcycle lookup page to choose your year, make, model, and engine before you order.
AMSOIL motorcycle oil families at a glance
| Family | Common viscosity | Best fit | Where to buy |
|---|---|---|---|
| V-Twin Synthetic | 20W-50 (also 20W-40, 15W-60, SAE 60) | Harley-Davidson Big Twin and Sportster, air-cooled push-rod | Buy online | Product details |
| Metric Synthetic | 10W-40 (also 10W-30, 5W-40, 15W-50) | Honda, Yamaha, Kawasaki, Suzuki, BMW, KTM four-strokes | Buy online | Product details |
| Dirt Bike Synthetic | 10W-40 (also 10W-50, 10W-60) | 4-stroke MX and enduro, KTM, Husqvarna, Honda CRF, Yamaha YZF | Buy online | Product details |
Match your owner's manual first
Every motorcycle ships with a specific viscosity grade and a JASO category called out in the owner's manual. Common modern examples are SAE 10W-40 with JASO MA2 for liquid-cooled metric four-strokes, SAE 20W-50 with JASO MA for Harley-Davidson Big Twin, and SAE 10W-40 or 10W-50 with JASO MA for off-road four-strokes.
Run only oils that carry the JASO MA or JASO MA2 certification on the label. Energy-conserving passenger-car oils with the API starburst symbol or "resource conserving" language contain friction modifiers that cause wet-clutch slip in shared-sump motorcycles. The Harley-Davidson oil guide and dirt bike oil guide cover the brand-specific picks in detail.
V-Twin: Harley-Davidson and air-cooled push-rod engines
AMSOIL 20W-50 Synthetic V-Twin Motorcycle Oil is the standard pick across Twin Cam, Milwaukee-Eight, Evolution, and Sportster engines. It is JASO MA/MA2 certified, 100% synthetic, and engineered to hold viscosity at the sustained high oil temperatures a V-Twin produces in summer touring. Cold-climate riders can step to 20W-40 V-Twin; very hot, sustained-load riders can step up to SAE 60 V-Twin. The full V-Twin lineup, including primary fluid and oil change kits, is on AMSOIL's V-Twin motorcycle page.
Metric: Japanese and European four-stroke street bikes
AMSOIL 10W-40 Synthetic Metric Motorcycle Oil covers most Honda, Yamaha, Kawasaki, and Suzuki four-strokes with the 10W-40 spec, and the matching 10W-30, 5W-40, and 15W-50 grades cover bikes spec'd for those viscosities. The full metric lineup, including transmission and primary fluids for unit-construction engines, lives on AMSOIL's street and adventure page.
Dirt Bike: 4-stroke MX, enduro, and trail
AMSOIL 10W-40 Synthetic Dirt Bike Oil is the standard pick for 4-stroke MX and enduro engines, with the 10W-50 and 10W-60 grades available for hotter operating environments and bigger displacement. The deeper breakdown, including 2-stroke premix ratios and transmission fluid pairings for unit-construction motors, lives in the dirt bike oil guide.
Bottom line: which AMSOIL motorcycle oil should you pick?
- Harley-Davidson Big Twin or Sportster. Pick AMSOIL 20W-50 V-Twin (also online from AMSOIL).
- Honda, Yamaha, Kawasaki, Suzuki, BMW, or KTM street four-stroke. Pick AMSOIL 10W-40 Metric (also online from AMSOIL) in your owner-spec viscosity.
- 4-stroke MX or enduro. Pick AMSOIL 10W-40 Dirt Bike (also online from AMSOIL).
- 2-stroke MX or trail. See the dirt bike oil guide for AMSOIL Dominator and Interceptor 2-stroke picks.
Save on AMSOIL with Preferred Customer pricing
AMSOIL Preferred Customer membership is $20 USD per year ($10 USD for a six-month trial) and unlocks up to 25% off on every product, with free shipping on qualifying orders. Add the membership to the same cart as your order and qualifying products switch to member pricing on that checkout, with no separate sign-up step. See the breakdown on the AMSOIL Preferred Customer page, or sign up directly through the AMSOIL Preferred Customer enrollment page.
AMSOIL motorcycle oil FAQ
What is the difference between V-Twin and metric motorcycle oil?
V-Twin oil is built for air-cooled push-rod engines that run hot, with a 20W-50 viscosity baseline. Metric oil is built for liquid-cooled four-stroke engines that run thinner viscosities (10W-30, 10W-40, 5W-40), share the sump with the wet clutch, and need JASO MA/MA2 friction. Pick by what your owner's manual specifies, not by the brand of the bike.
Is AMSOIL motorcycle oil JASO MA-certified?
Yes. AMSOIL Synthetic Motorcycle Oil in V-Twin, metric, and dirt bike formulations carries the JASO MA/MA2 wet-clutch certification. Energy-conserving passenger-car oils marked API SP with the starburst symbol are not safe in shared-sump motorcycles because the friction modifiers slip the wet clutch.
How often should I change motorcycle oil?
Most street motorcycles get an oil and filter change every 5,000 to 7,500 miles with full synthetic, or once per season for short-mileage riders. Sport bikes that see redline regularly should change at the shorter end of that range. Dirt bikes change much more often, typically every 5 to 15 hours of riding depending on intensity.
Can I use car oil in a motorcycle?
No. Modern energy-conserving passenger-car oils contain friction modifiers that cause wet-clutch slip in shared-sump motorcycles. Use only oils that carry the JASO MA or MA2 certification on the label. AMSOIL motorcycle oil meets JASO MA/MA2 across the V-Twin, metric, and dirt bike lineup.
Which AMSOIL oil should I use in a Honda, Yamaha, Kawasaki, or Suzuki?
Use AMSOIL 10W-40 Synthetic Metric Motorcycle Oil on most Honda, Yamaha, Kawasaki, and Suzuki four-strokes with the 10W-40 spec. Bikes spec'd for 10W-30, 5W-40, or 15W-50 use the matching AMSOIL metric variant. Confirm the viscosity in the owner's manual, and confirm JASO MA on the label.
Where do I buy AMSOIL motorcycle oil?
Order online from AMSOIL on the motorcycle oil category page, with subcategories for V-Twin, street and adventure, and off-road motorcycle. The matching motorcycle oil overview covers the same lineup with side-by-side spec comparisons.
Order AMSOIL motorcycle oil
Order online from AMSOIL's motorcycle oil page. To unlock up to 25% off, add an AMSOIL Preferred Customer membership to the same cart and qualifying products switch to member pricing immediately, with no separate sign-up step.