JASO MA2
10W-40 Metric
The volume bottle. Honda, Yamaha, Kawasaki, Suzuki, BMW, Triumph — if the manual says 10W-40 motorcycle oil, this is the fill.
- Pour
- −54°F
- Best for
- Sport, adventure, touring, and metric cruisers
Bikes · Metric series
Metric motorcycle oil. Wet clutch, shared sump, one family.
10W-40 is the bottle most Japanese and Euro bikes spec. 10W-30, 5W-40, and 15W-50 sit in the same JASO MA2 series — not car oil poured into a transmission.
Video · 2:47
Watch: How AMSOIL tests for clutch feel
AMSOIL powersports expert Len Groom explains why clutch feel matters in a wet-clutch dirt bike oil, and the extreme-start test AMSOIL developed to measure it.
The metric series
Four viscosities. Same clutch chemistry.
Fredric Riech specs the metric series for Honda, Yamaha, Kawasaki, Suzuki, BMW, Triumph, KTM, and Ducati that share oil between engine and transmission. Dirt bikes that spec 10W-40 get Dirt Bike Oil, not Metric 10W-40. Harley and Indian V-twins are a different bottle — use the lookup. Dealer number 1245102.
JASO MA2
10W-30 Metric
The lighter Japanese spec. Same wet-clutch chemistry as 10W-40, thinner at a Wasilla cold start. Common on Honda and Kawasaki that call 10W-30.
- Pour
- −54°F
- Best for
- Bikes that spec 10W-30, shoulder-season riding
JASO MA2
5W-40 Metric
The 5W winter number with a 40-weight hot film. Aprilia, BMW, Can-Am, Husqvarna, Moto Guzzi when the book wants a 5W-40 motorcycle oil.
- Pour
- −54°F
- Best for
- Euro and Can-Am bikes that spec 5W-40
JASO MA2
15W-50 Metric
The high-heat metric grade. Ducati, BMW Boxer, KTM, Triumph, and other bikes that spec 15W-50 in a shared sump.
- Pour
- −38°F
- Best for
- Euro twins and adventure bikes that spec 15W-50
Dirt bikes · 10W-40
10W-40 dirt bike oil. Not the metric bottle.
Dirt Bike Oil is the off-road 10W-40. Consistent clutch feel under repeated starts, and a film that holds on gears when a CRF or a two-stroke transmission is hot. Honda, Yamaha, Kawasaki, Suzuki, Husqvarna — when the book says 10W-40 motorcycle oil and the bike is a dirt bike.
- Pour
- −40°F
- Grade
- 10W-40
- Spec
- JASO MA
Separate-sump bikes, including the Honda CRF, and many two-stroke dirt bikes that run 10W-40 in the transmission. Follow the manufacturer’s interval. Street bikes stay on the metric series above.
Shop Dirt Bike OilProduct line
The questions riders ask before they switch.
01
Are AMSOIL metric motorcycle oils wet-clutch compatible?
Yes. The metric series meets JASO MA/MA2 friction requirements. No friction modifiers. Shared-sump engines, transmissions, and wet clutches get smooth engagement instead of slip and glaze. That is the difference between motorcycle oil and car oil.
02
Can I just run Signature Series or another car oil in my bike?
No. Automotive oils are built for engines only. They use friction modifiers that can make a wet clutch chatter or slip. Metric motorcycle oil has to protect the engine, the gears, and the clutch from one sump — and survive shear that a commuting 0W-20 never sees. Use the metric bottle.
03
Will switching to AMSOIL void my motorcycle warranty?
No. AMSOIL metric oils meet the API and JASO specs the manufacturer lists. The Magnuson-Moss Warranty Act bars a brand from requiring their oil unless they supply it free. Keep receipts and follow the listed viscosity. AMSOIL also backs the oil with its own limited warranty.
04
How often should I change metric motorcycle oil?
Up to twice the motorcycle manufacturer’s recommended interval, or one year, whichever comes first. If you are not running an AMSOIL Ea motorcycle filter, change the filter on the OEM schedule. Track days and Alaska short-trip storage count as severe — stay closer to the book. Dirt bikes on Dirt Bike Oil follow the manufacturer’s interval, not the metric drain.
05
Which viscosity do I buy — 10W-30, 10W-40, 5W-40, or 15W-50?
For a street bike, the one on the owner’s manual, confirmed on the AMSOIL motorcycle lookup. 10W-40 is the most common Honda/Yamaha/Kawasaki/Suzuki/BMW fill. 10W-30 when the book says 10W-30. 5W-40 for bikes that want a 5W winter grade. 15W-50 for Ducati, BMW Boxer, KTM, and Triumph that spec it. A dirt bike that specs 10W-40 is Dirt Bike Oil, not Metric 10W-40. Do not guess a heavier oil for Alaska heat that is not in the spec.
06
How is Dirt Bike Oil different from the metric oils?
Same company, different job. The metric series is for street bikes that share one sump between the engine, gearbox, and wet clutch. It comes in four viscosities, meets JASO MA2, and can run up to twice the street interval or one year. Dirt Bike Oil is only a 10W-40, meets JASO MA, and is built for dirt bikes — Honda, Yamaha, Kawasaki, Suzuki, and Husqvarna — including separate-sump engines like the CRF and many two-strokes that run 10W-40 in the transmission. Clutch feel is the point of Dirt Bike Oil: it held consistent lever action through 32 simulated race starts in AMSOIL’s test, where a leading OEM oil faded after 16. Pour point is −40°F on Dirt Bike Oil versus −54°F on metric 10W-40, so the street bottle is the colder-flowing 10W-40. Change Dirt Bike Oil on the manufacturer’s interval.
07
Can I run metric 10W-40 in a dirt bike, or Dirt Bike Oil on the street?
Don’t swap them because the label both says 10W-40. Metric 10W-40 is the street shared-sump oil. Dirt Bike Oil is the dirt-bike oil, including separate-sump and two-stroke transmission fills. A street bike that specs 10W-40 motorcycle oil gets Metric 10W-40. A dirt bike that specs 10W-40 gets Dirt Bike Oil. If the lookup lists a different grade, follow the lookup.
Look up the bike
Year, make, model. Oil, filter, and fork fluid.
AMSOIL.com motorcycle lookup, tagged to dealer 1245102. Metric and V-twin. Opens in the store so Preferred Customer pricing follows the account.
Not a metric bike?
Harley-Davidson oil changes are a different package — the 20W-50 V-Twin kits with a chrome filter, not the metric series on this page. Indian and Victory also use V-Twin oil. Confirm on the lookup or call (907) 350-7366.
Harley oil change kits