AMSOIL guide
AMSOIL Dirt Bike Oil Guide
AMSOIL builds three SAE grades of 100% synthetic 4-stroke dirt bike oil: 10W-40 for most MX and enduro applications, 10W-50 for hotter and bigger-displacement engines, and 10W-60 for the most extreme heat and load. All three carry the JASO MA wet-clutch certification and run safely in the shared engine, clutch, and gearbox sump that almost every modern 4-stroke dirt bike uses. Match the viscosity to your owner's manual and change short.
Shop AMSOIL 10W-40 Dirt Bike Oil
AMSOIL dirt bike oil lineup at a glance
| Product | Best fit | Where to buy |
|---|---|---|
| 10W-40 Synthetic Dirt Bike (DB40) | Most KTM, Husqvarna, Honda CRF, Yamaha YZF, Kawasaki KX-F | Buy online | Product details |
| 10W-50 Synthetic Dirt Bike | Hotter operating environments, larger displacement | Buy online | Product details |
| 10W-60 Synthetic Dirt Bike | Extreme heat and load, BMW G450X-style applications | Buy online | Product details |
| Dominator 2-Stroke Racing | 2-stroke MX and racing premix or injector | Buy online |
| Interceptor 2-Stroke | 2-stroke trail and lower-load applications | Buy online |
Match your owner's manual first
Every dirt bike ships with a specific viscosity grade and a JASO category called out in the owner's manual. Common examples are SAE 10W-40 with JASO MA for most current 4-stroke MX and enduro models, with 10W-50 and 10W-60 listed for very hot operating environments. Run only oils that carry the JASO MA certification on the label. Energy-conserving passenger-car oils contain friction modifiers that cause wet-clutch slip on a shared-sump dirt bike.
4-stroke MX, enduro, and trail
AMSOIL 10W-40 Synthetic Dirt Bike Oil is the standard pick for KTM 250/350/450 SX-F and EXC-F, Husqvarna FC and FE, Honda CRF250R/450R, Kawasaki KX250F/450F, Yamaha YZ250F/450F, and Suzuki RM-Z250/450 4-stroke MX and enduro models.
For hotter climates, larger displacement, or sustained high-rev work, step to 10W-50. For the most extreme heat and load, 10W-60 is the heaviest grade in the lineup. All three carry JASO MA and are safe across engine, clutch, and gearbox in shared-sump bikes.
2-stroke MX, trail, and racing
For 2-stroke MX and racing applications (KTM 125/250/300 SX/EXC, Husqvarna TC/TE, Yamaha YZ250, Honda CR125/250), AMSOIL Dominator Synthetic 2-Stroke Racing Oil is the premix and injector pick. For 2-stroke trail and lower-load applications, AMSOIL Interceptor Synthetic 2-Stroke Oil works at standard premix ratios. Both ship from AMSOIL's off-road motorcycle page. Common premix ratios are 32:1 and 40:1; verify against your engine builder's published recommendation.
Change interval and filter pairing
Dirt bike oil sees harder service per minute than almost any other engine oil application. The combination of high RPM, gear shock loading from the shared sump, and frequent clutch slip during MX and enduro work shears the oil hard. Plan on a change interval of 5 hours for aggressive MX and racing, and 10 to 15 hours for trail and enduro at moderate intensity. Change the oil filter at the same interval.
Bottom line: which AMSOIL dirt bike oil should you pick?
- Standard 4-stroke MX or enduro. Pick AMSOIL 10W-40 Dirt Bike (also online from AMSOIL).
- Hot climate, larger displacement, or sustained high-rev. Pick AMSOIL 10W-50 Dirt Bike.
- Extreme heat and load. Pick AMSOIL 10W-60 Dirt Bike.
- 2-stroke racing or aggressive MX. Pick AMSOIL Dominator Synthetic 2-Stroke Racing Oil.
- 2-stroke trail or lower-load. Pick AMSOIL Interceptor Synthetic 2-Stroke Oil.
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 dirt bike oil FAQ
How often should I change dirt bike oil?
Aggressive MX and high-rev racing applications: every 5 hours of riding. Trail and enduro at moderate intensity: every 10 to 15 hours. Always change the oil filter at the same interval. AMSOIL Synthetic Dirt Bike Oil holds up across the published interval, but the gearbox and clutch shear oil hard, so short changes pay off.
Is AMSOIL Dirt Bike Oil JASO MA-rated?
Yes. AMSOIL 10W-40 Synthetic Dirt Bike Oil and the matching 10W-50 and 10W-60 grades carry the JASO MA wet-clutch certification and are designed for the engine, clutch, and gearbox of a 4-stroke dirt bike that shares one sump across all three.
What viscosity should I run in a 4-stroke dirt bike?
Can I use car oil in a 4-stroke dirt bike?
No. Modern energy-conserving passenger-car oils contain friction modifiers that cause wet-clutch slip in shared-sump dirt bikes. Use only oils that carry the JASO MA or MA2 certification on the label.
What about 2-stroke dirt bike oil?
For 2-stroke MX and trail bikes, AMSOIL builds Dominator Synthetic 2-Stroke Racing Oil for premix and injector use, and Interceptor Synthetic 2-Stroke Oil for trail and lower-load applications. Both ship from AMSOIL's off-road motorcycle page. Premix ratio depends on the engine; common ratios are 32:1 and 40:1.
Should I use a separate transmission fluid in my dirt bike?
Most modern 4-stroke dirt bikes share one sump across engine, clutch, and gearbox, so the engine oil is the transmission fluid. A handful of older or specialty bikes have a separate gearbox; in that case use a dedicated AMSOIL synthetic gear oil sized to the manufacturer's viscosity.
Order AMSOIL dirt bike oil
Order online from AMSOIL's off-road motorcycle 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.