Specially engineered and formulated for maximum horsepower and protection without the shortcomings of using automotive, PAG or mineral-based karting oils in a high-revving, air-cooled, splash-lubed environment. Resists rust, corrosion, and foaming. Safe for use in gasoline and alcohol-burning stock or modified engines.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for Briggs & Stratton Synthetic 4T Racing Oil.
Briggs & Stratton Synthetic 4T Racing Oil is a co-branded synthetic competition oil developed jointly by Briggs & Stratton engineers and AMSOIL for stock and modified small-displacement air-cooled four-stroke racing engines. The formula targets kart, junior drag, quarter midget, and other small-engine race classes that punish automotive, PAG, or mineral-based karting oils with sustained high rpm, high heat, and splash lubrication.
Maximizes horsepower without sacrificing wear protection
Synthetic 4T Racing Oil combines the horsepower of a lite oil with the wear protection of a heavier oil. Specialized friction modifiers and advanced additives reduce energy loss due to friction so racers can put more power to the ground. In Four-Ball Wear testing (ASTM D4172 at 40 kg, 75°C, 1200 rpm, 1 hour) the oil returns a 0.36 mm scar, an indicator of the durable lubricating film the formula holds together under load.
Engineered for air-cooled racing heat
Pure synthetic base oils resist the extreme heat common to air-cooled racing engines better than conventional oils, and increased thermal stability helps lower operating temperatures while guarding against the sludge and deposits that rob power. Flash Point (ASTM D92) lands at 226°C (439°F) and Fire Point at 244°C (471°F), with NOACK Volatility (ASTM D5800) measured at 9.7 percent weight loss. Viscosity Index (ASTM D2270) of 156 keeps the film stable as cylinder-head temperatures swing across a heat race.
Anti-foam, anti-shear performance at high rpm
Powerful anti-foam agents resist the foam that builds in high-rpm splash-lubricated four-strokes, and High-Temperature/High-Shear viscosity (ASTM D5481, 150°C, 1.0 x 10⁶ s⁻¹) holds at 4.2 cP. That combination forms a durable lubricating film between piston rings, cylinders, valves, and bearings, helping reduce wear under the sustained throttle and shearing forces a stock or modified kart engine sees lap after lap.
Corrosion control between races and during storage
A race engine sits as much as it runs. Corrosion inhibitors built into Synthetic 4T Racing Oil guard against rust forming between race weekends and during longer off-season storage, so a freshly built engine does not lose ring seal or bearing surface to humidity while it waits for the next event.
Compatible with gasoline and alcohol fuel
The oil is recommended for both gasoline-fueled and alcohol-fueled stock or modified competition engines, including methanol classes, and is compatible with mineral oils for first-fill conversion. To switch a previously run engine over, drain the existing oil, refill with Synthetic 4T Racing Oil, run the engine at idle to low speed for two to three minutes, then drain and refill with fresh Synthetic 4T Racing Oil.
Recommended applications and service intervals
Synthetic 4T Racing Oil is purpose-built for stock and modified small-displacement air-cooled racing engines. The formula is recommended for any four-stroke air-cooled competition engine, whether single-cylinder or multi-cylinder, and whether splash-lubricated or pressure-lubricated, including Briggs & Stratton V-Twin engines that require the viscosity and lubricating properties listed in the technical table below.
Kart racing, junior drag, quarter midget, and similar small-displacement race classes.
Briggs & Stratton four-stroke racing engines, single-cylinder and V-Twin variants requiring the listed viscosity.
Gasoline-fueled and alcohol-fueled (methanol) stock and modified competition engines.
Service life follows the original equipment manufacturer or engine builder recommendation; this is a competition oil, not an extended-drain street oil.
Compatible with mineral oils for the first conversion fill, with no aftermarket additives required for normal racing use. For non-racing four-stroke equipment such as mowers, generators, lawn tractors, and pressure washers, choose the appropriate AMSOIL synthetic small-engine oil instead of a race-specific formula.
Typical technical properties
Property
Value
Kinematic Viscosity at 100°C, cSt (ASTM D445)
11.6
Kinematic Viscosity at 40°C, cSt (ASTM D445)
72.2
Viscosity Index (ASTM D2270)
156
Pour Point, °C (°F) (ASTM D97)
-46 (-51)
Flash Point, °C (°F) (ASTM D92)
226 (439)
Fire Point, °C (°F) (ASTM D92)
244 (471)
Four-Ball Wear Test, scar, mm (ASTM D4172 at 40 kg, 75°C, 1200 rpm, 1 hr)
0.36
NOACK Volatility, % weight loss (ASTM D5800)
9.7
High-Temperature/High-Shear Viscosity at 150°C, 1.0 x 10⁶ s⁻¹, cP (ASTM D5481)
4.2
Order Briggs & Stratton Synthetic 4T Racing Oil
Available sizes include the one-quart bottle (GBS2960-EA) and the case of twelve quarts (GBS2960-CA). The product is covered by the AMSOIL Limited Warranty for confirmed defects in materials and workmanship. Confirm application match for the racing class and engine builder spec with the AMSOIL vehicle lookup guide and the small engine oil guide, then place an order for Briggs & Stratton Synthetic 4T Racing Oil in the size needed.
Most power we see on dyno with Flat kart motors period. we break in every motor with the break in oil as well
By Matt on May 22, 2026.
Would recommend this to a friend.
Just what the engine ordered
As the BC Briggs racing dealer, ( and this is what is recommended by Briggs themselves ) I sell this to all my customers along with the Amsoil Break-in Oil. To date I have had no negative issues with these products.
By Dana from Kelowna on January 12, 2026.
Briggs 4T
This stuff works amazing, one of the best product I've ever used in our Briggs and Stratton W/F engine.
What is Briggs & Stratton Synthetic 4T Racing Oil?
It is a co-branded synthetic four-stroke competition oil developed jointly by Briggs & Stratton engineers and AMSOIL for air-cooled racing engines. Briggs & Stratton requested an oil capable of maximizing horsepower while handling the intense heat and shearing forces inside its competition four-stroke engines, and Synthetic 4T Racing Oil is the result. It is tested and validated by Briggs & Stratton and AMSOIL.
Which engines and race classes is it designed for?
Stock and modified small-displacement air-cooled four-stroke racing engines used in kart, junior drag, quarter midget, and other small-engine race classes. The formula is recommended for any four-stroke air-cooled competition engine, single-cylinder or multi-cylinder, splash-lubricated or pressure-lubricated, including Briggs & Stratton V-Twin race engines that require the listed viscosity.
Can it run with methanol or other alcohol fuel?
Yes. Synthetic 4T Racing Oil is recommended for both alcohol-fueled and gasoline-fueled stock and modified competition engines, which covers class rules that allow methanol as well as classes that mandate gasoline.
Why not just run automotive synthetic oil in a race kart?
Automotive, PAG, and conventional karting oils tend to fall short in a high-revving, air-cooled, splash-lubed environment. Synthetic 4T Racing Oil is engineered to combine the horsepower of a lite oil with the wear protection of a heavier oil, and the additive package targets the foam, heat, and shear that build inside an air-cooled racing four-stroke at sustained high rpm.
How should the oil be changed when converting from another brand?
Do not mix with other oils when converting. Drain the existing oil, refill with Synthetic 4T Racing Oil, run the engine at idle to low speeds for two to three minutes, drain again, then refill with fresh Synthetic 4T Racing Oil before the race weekend.
How often should it be changed in a race engine?
This is a competition oil, not an extended-drain street oil. Service life follows the original equipment manufacturer or engine builder recommendation for the specific class, displacement, and fuel. Many race engine builders specify a fresh fill per race day or per heat session.
Does using it affect the Briggs & Stratton engine warranty?
Synthetic 4T Racing Oil is tested and validated by Briggs & Stratton and AMSOIL for use in Briggs & Stratton four-stroke racing engines. Using AMSOIL synthetic lubricants does not void original equipment manufacturer warranties; refer to the engine manufacturer published warranty terms for confirmation.
