Amsoil Authorized Dealers John & Zenaida Cardell

10W-40 Synthetic Dirt Bike Oil (DB40)

Amsoil 10W-40 Synthetic Dirt Bike Oil (DB40)

Product Information

Engineered to deliver the performance attributes most requested by on- and off-track dirt bike riders, including consistent clutch feel. Consistent clutch feel is the result of “friction durability,” so whether deep into a race or deep in the woods, riders can feel confident their clutch will perform from start to finish. AMSOIL-exclusive advanced chemistry provides outstanding engine reliability for worry-free operation under severe conditions.


AMSOIL INC., the premier manufacturer of synthetic motorcycle lubricants, focuses on improving lubricant performance so riders can focus on improving their performance on the trail or the track. That's why AMSOIL is the Official Oil of Monster Energy Supercross, AMSOIL Arenacross, AMSOIL GNCC and the AMA Amateur Nationals.

Package Sizes (MCT)

MCTQT (MCTQT-CA)QuartCase of 12
MCT1G (MCT1G-EA)GallonEach
MCTQT (MCT1G-CA)GallonCase of 4
MCTQT (MCTQT-30)30-Gallon DrumEach
MCTQT (MCTQT-55)55-Gallon DrumEach
MCTQT (MCTQT-27)275-Gallon ToteEach

Delivers Confidence in Clutch Feel

AMSOIL Synthetic Dirt Bike Oil’s superior friction-durability properties help minimize clutch slippage, fade and chatter, giving riders consistent clutch feel during takeoffs or when maneuvering around obstacles on the trail. In an extreme simulated-start test, AMSOIL Synthetic Dirt Bike Oil continued to deliver consistent clutch feel following 32 simulated race starts, while a leading original equipment manufacturer (OEM)-branded oil demonstrated inconsistent clutch-lever action and poor clutch feel after 16 starts. The clutch plates lubricated with AMSOIL Synthetic Dirt Bike Oil remained clean and in good overall condition, while the plates using the OEM oil revealed discoloration and wear. AMSOIL Synthetic Dirt Bike Oil’s superior performance helps instill in riders the confidence that their bikes will perform consistently in all types of riding conditions.

Protects Against Wear

AMSOIL Synthetic Dirt Bike Oil withstands high-rpm operation, extreme heat and mechanical shear. Its synthetic base oils naturally resist viscosity loss and provide a protective film against wear to gears, bearings and pistons. Its anti-wear additives provide an extra measure of protection, promoting long component life to help riders get the most out of their bikes.

Exteme Simulated Start Test

  • Delivers confidence in clutch feel
  • Superior protection against gear, bearing & piston wear
  • Maximizes horsepower
  • Helps extend clutch life


AMSOIL Synthetic Dirt Bike Oil underwent extensive on-track testing in the bikes of AMSOIL-sponsored professional riders on the GEICO/AMSOIL/Honda Factory Connection and Team Babbitt's racing teams. A combination of racer feedback and lab testing allowed AMSOIL to fine-tune AMSOIL Synthetic Dirt Bike Oil for outstanding wear protection and consistent clutch feel – benefits riders demand.


10W-40 Synthetic Dirt Bike Oil: recommended for Honda®, Yamaha®, Kawasaki®, Suzuki®, Husqvarna® and other dirt bikes where 10W-40 motorcycle oil is used. Recommended for separate-sump applications such as Honda CRF, and many two-stroke dirt bikes. JASO MA, API SG, SJ, SH, SL.

*All trademarked names are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use.


AMSOIL Synthetic Dirt Bike Oil should be changed according to the vehicle manufacturer's recommendations.

Amsoil 10W-40 Synthetic Dirt Bike Oil (DB40)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445)14.2
Kinematic Viscosity @ 40°C, cSt (ASTM D-445)93.5
Viscosity Index (ASTM D-2270)156
Pour Point °C (°F) (ASTM D-97)-44 (-47)
Flash Point °C (°F) (ASTM D-92)246 (475)
Fire Point, ºC (ºF) (ASTM D92)254 (489)
NOACK Volatility, % weight loss (g/100g) (ASTM D-5800)4.0
Four-Ball Wear Test (ASTM D4192 @ 40 kgf, 150°C, 1800 rpm, 1 hr) scar, mm0.39
Total Base Number (ASTM D2896)6.62
Foam (ASTM D5182, Sequence I, II & III)0/0, 20/0, 0/0