AMSOIL 100% Synthetic Dirt Bike Transmission Fluid
Advanced synthetic technology provides superior film strength to protect high-torque transmissions. Wet-clutch compatible. Friction-modifier-free formulation for confident, consistent clutch performance. Anti-wear properties promote extended transmission and clutch life. Use in two- and four-stroke dirt bikes that use a separate sump requiring transmission fluid with the JASO MA specification, including those made by Honda,* Yamaha,* Kawasaki,* Suzuki,* Husqvarna,* and KTM.*
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL 100% Synthetic Dirt Bike Transmission Fluid.
AMSOIL 100% Synthetic Dirt Bike Transmission Fluid
AMSOIL 100% Synthetic Dirt Bike Transmission Fluid is a low-viscosity, wet-clutch-rated gearbox oil engineered for two- and four-stroke dirt bikes that route the engine and transmission into separate sumps. The friction-modifier-free formulation meets the JASO MA wet-clutch specification, and the product carries the AMSOIL Limited Warranty.
Confident wet-clutch engagement
Dirt-bike clutch packs live or die by the friction profile of the fluid surrounding them. AMSOIL Synthetic Dirt Bike Transmission Fluid is built without aftermarket friction modifiers so the clutch plates bite cleanly during launches and out of corners. Riders feel a consistent engagement point on the lever instead of the slipping, grabbing, and fading that thinner motor oils or modified ATFs can produce when temperatures climb during enduro and harescramble laps.
The low-viscosity construction is intentional: thinner fluid lets clutch plates clamp with less hydraulic cushion, which the formulation translates into more aggressive clutch feel and quicker holeshots without sacrificing protection.
Shear-stable film for high-torque gearboxes
Inside a small dirt-bike gearbox, gears mesh hard, the clutch basket spins under load, and the same charge of fluid takes a beating shift after shift. Conventional oils can shear out of grade and lose film thickness, which leads to metal-to-metal contact and pitted gear faces. The synthetic base oils used in AMSOIL Synthetic Dirt Bike Transmission Fluid resist mechanical shear and viscosity loss, holding a kinematic viscosity of 10.3 cSt at 100°C (ASTM D445) and a high viscosity index of 144 (ASTM D2270). That stability keeps a consistent protective film across temperature, even after extended ride days in the desert or after consecutive moto sessions.
Anti-wear chemistry for gears and clutch plates
Premium anti-wear additives reinforce the fluid film between gear teeth, dogs, and shift forks under heavy clutch usage. The result is reduced wear on transmission gears and longer service life on friction plates and steels, which lowers the frequency of clutch rebuilds for riders who ride hard or race competitively.
Cold-start fluidity and high-heat stability
A pour point of -40°C (-40°F) (ASTM D97) keeps the fluid mobile during cold-morning starts and winter trail riding, so the clutch is fully wetted from the first kick or button press. On the high end, a flash point of 246°C (475°F) and fire point of 274°C (525°F) (ASTM D92) give the formulation thermal headroom for hard-charging, heat-soaked motos.
Built for the bikes, not borrowed from the engine
Two-stroke dirt bikes from KTM, Husqvarna, Honda, Yamaha, Kawasaki, and Suzuki use a separate transmission and clutch sump that the engine premix never reaches, so a dedicated transmission fluid is required. Many four-stroke MX and off-road models also use a discrete gearbox sump rather than sharing oil with the engine. AMSOIL Synthetic Dirt Bike Transmission Fluid is purpose-built for these gearbox architectures, in contrast to four-stroke shared-sump bikes that need a JASO MA/MA2 motorcycle motor oil instead.
Recommended applications and service intervals
Use AMSOIL Synthetic Dirt Bike Transmission Fluid in two- and four-stroke dirt bikes that use a separate transmission sump requiring a JASO MA wet-clutch fluid, including models made by Honda, Yamaha, Kawasaki, Suzuki, Husqvarna, and KTM. Match the fluid to gearbox service in particular, not to the engine: the 2-stroke top end runs on premix or injector oil, and the gearbox runs on this fluid.
Normal trail and recreational riding: change the fluid according to the dirt-bike manufacturer service schedule listed in the owner manual.
Severe service such as motocross, enduro, harescramble, or extended hot-weather riding: shorten the change interval relative to the OEM schedule because gearbox shear and clutch debris accumulate faster.
Confirm the correct oil for the engine separately using the AMSOIL vehicle lookup guide or the dirt bike oil guide, since 2-stroke engines take premix and most 4-stroke MX bikes take a wet-clutch motorcycle oil.
Modified, high-compression race engines and machines using alternative fuels should be referred to the AMSOIL technical team before substitution.
Drain the gearbox warm to remove suspended clutch material, refill to the OEM capacity at the inspection plug or sight glass, and torque the drain bolt to the service-manual spec. Aftermarket clutch additives are not required and are not recommended on top of this fluid.
Typical technical properties
Property
Value
Kinematic Viscosity at 100°C, cSt (ASTM D445)
10.3
Kinematic Viscosity at 40°C, cSt (ASTM D445)
65.1
Viscosity Index (ASTM D2270)
144
Pour Point, °C (°F) (ASTM D97)
-40 (-40)
Flash Point, °C (°F) (ASTM D92)
246 (475)
Fire Point, °C (°F) (ASTM D92)
274 (525)
Wet-clutch specification
JASO MA
Order AMSOIL 100% Synthetic Dirt Bike Transmission Fluid
AMSOIL 100% Synthetic Dirt Bike Transmission Fluid ships in quart bottles (DBTFQT-EA) and case packs of twelve quarts (DBTFQT-CA), backed by the AMSOIL Limited Warranty. Confirm gearbox application match with the AMSOIL vehicle lookup guide and pair the gearbox fluid with the right engine oil from the AMSOIL dirt bike oil guide before placing an order. Order Now.
Two-stroke dirt bikes always need a dedicated transmission oil because the engine runs on premix or injector oil and the gearbox is a separate sump that is not lubricated by the fuel charge. Many four-stroke motocross and off-road bikes also use a separate gearbox sump that calls for a JASO MA fluid like AMSOIL 100% Synthetic Dirt Bike Transmission Fluid. Confirm the layout for the specific model in the owner manual or with the AMSOIL vehicle lookup guide.
What transmission oil does a 2-stroke KTM, Husqvarna, or Honda dirt bike take?
The transmission and wet clutch in two-stroke dirt bikes from KTM, Husqvarna, Honda, Yamaha, Kawasaki, and Suzuki take a JASO MA-rated, friction-modifier-free transmission fluid. AMSOIL 100% Synthetic Dirt Bike Transmission Fluid is built for that application and supports consistent clutch engagement across temperature ranges and riding intensities.
Can motor oil or ATF be used in a dirt bike gearbox instead?
Substituting passenger-car motor oil, high-mileage motor oil, or automatic transmission fluid is not recommended. Those products contain friction modifiers or detergent packages that can cause clutch slip, grab, or fade in a wet-clutch gearbox, and many shear out of grade quickly under heavy clutch usage. A purpose-built JASO MA gearbox fluid such as AMSOIL Synthetic Dirt Bike Transmission Fluid is the correct fit.
What is the difference between transmission oil and gear oil for a 2-stroke?
The terms are used interchangeably for two-stroke dirt bikes because the gearbox combines transmission gears and the wet clutch in the same case. The required fluid is a low-viscosity, JASO MA, friction-modifier-free transmission oil rather than a heavy 75W-90 or 80W-90 hypoid gear lube. Hypoid gear oils carry sulfur-phosphorus extreme-pressure additives that are aggressive toward yellow metals and clutch friction surfaces and should not be used in this gearbox.
How often should dirt bike transmission fluid be changed?
Follow the change interval listed by the dirt-bike manufacturer in the owner manual as a baseline. Riders running motocross, enduro, harescramble, or hot-weather conditions should shorten the interval, since suspended clutch material and shear stress accumulate faster in those duty cycles. The fluid should also be drained any time clutch components are replaced.
Will this transmission fluid affect clutch feel or holeshots?
The low-viscosity, friction-modifier-free formulation is designed to deliver crisp, aggressive clutch feel for launches and corner exits. The friction-durability profile resists fade under repeated heavy clutch usage, which helps maintain a consistent engagement point through long motos and trail rides.
Does using AMSOIL Synthetic Dirt Bike Transmission Fluid void the dirt bike warranty?
No. Using AMSOIL synthetic lubricants does not void a manufacturer warranty under the Magnuson-Moss Warranty Act so long as the fluid meets the specifications called for by the dirt-bike manufacturer. AMSOIL Synthetic Dirt Bike Transmission Fluid carries the AMSOIL Limited Warranty in addition to the OEM coverage.
