Since 2023, KTM has offered a big-bore two-stroke motocross bike in the form of the 300 SX. Like its smaller-displacement premix-burning siblings (the 125 SX and 250 SX), this open-class smoker features throttle body injection (TBI) and an electronic power valve, making it one of the most technologically advanced two-stroke dirt bikes on the market alongside Husqvarna’s and GasGas’ equivalent models.
To find out how much horsepower and torque the Ready to Race brand’s largest-displacement two-stroke motocross bike is capable of producing, we strapped it to our in-house Dynojet 250i dynamometer. In conducting multiple pulls, we documented maximum figures of 49.1 hp and 32.3 lb.-ft. of torque at the rear wheel. For comparison, that’s 1.3 hp less than the 2025 KTM 350 SX-F at peak, but 5.7 lb.-ft. of torque more than the mid-displacement thumper. Now, it’s time to find out what that two-stroke power is like in the dirt.
Related: 2025 KTM Motocross Bikes First Look
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