The peak power density of internal combustion engines has an overwhelming advantage. The current top-of-the-line 450cc four-stroke gas dirt bikes engine can generate 60 horsepower at 9000 RPM, with a power-to-weight ratio of 0.42 horsepower per kilogram. The top-of-the-line electric off-road motorcycle Stark Varg, with a maximum power of 80 horsepower, has a curb weight of 110 kilograms (power-to-weight ratio 0.27 horsepower per kilogram). This is because a high-speed piston engine has a power output of over 130 horsepower per liter of displacement, while a permanent magnet motor is limited by the saturated magnetic flux density of the magnetic material (about 1.4T for neodymium iron boron), and its continuous power density is approximately 5kW/kg. The actual test data of the 2023 AMA Super Trail Race shows that the Yamaha YZ450F can accelerate from 0 to 96 kilometers per hour on the straight track in just 3.8 seconds, which is 1.4 seconds faster than the Zero FXE.
The essential differences in energy storage media lead to significant variations in endurance parameters. The energy density of gasoline is approximately 12,000Wh/kg, while the current mass-produced lithium battery packs have a maximum of only 300Wh/kg. This means that a 9-liter fuel tank can store about 30 kilowatt-hours of electrical energy equivalent. Under continuous climbing conditions, a fuel vehicle can maintain a range of over 100 kilometers, while an electric off-road vehicle, with a battery pack capacity of 6kWh at 50% peak power output (about 40 horsepower), can only support 35 minutes of continuous output. ISDE endurance race data statistics show that gas motorcycles consume approximately 7 liters of fuel in an 80-kilometer forest track stage, while the same stage requires 11.5kWh of electricity (equivalent to a 38.3kg battery pack), with a weight increase of 58%.
The limit of a thermal management system determines its continuous output capacity. The cooling system of the four-stroke engine can handle a 6kW thermal load (under water temperature of 110℃), and in combination with the oil cooling system, it maintains a stable working temperature. However, the electric motor will experience irreversible demagnetization when the magnet temperature exceeds 180℃. In professional tests, the power attenuation of the KTM 350 SX-F was only 7% after continuous full throttle operation for 20 minutes, while the electric model Sur-Ron Light Bee X triggered the temperature protection after running at the same intensity for 8 minutes, resulting in a 40% power drop. The vehicle engineering report of the Dakar Rally indicates that at an ambient temperature of 50℃, the completion rate of gas motorcycles is 63% higher than that of electric models.
The dynamic response characteristics affect the handling accuracy. The two-stroke gas motorcycle can complete a 50% to 100% throttle opening response within 0.02 seconds, with a crankshaft moment of inertia of only 0.18kg·m². Although the motor has an instantaneous torque characteristic, due to the electronic control protection strategy (to prevent battery overcurrent), the full throttle command execution is delayed by 0.15 seconds. MotoGP rider test feedback shows that in the scenario of refueling after landing after a jump, the throttle correction accuracy of fuel-powered motorcycles is 30% higher than that of electric bikes. Especially in areas above 3,000 meters in altitude, the internal combustion engine ECU can automatically compensate for the air-fuel ratio (14.7:1) to maintain 95% power output, while the power loss of electric motors in thin air does not exceed 3%.
The difference in weight distribution alters the physical characteristics of control. Gas motorcycles concentrate 54% of their mass in the crankshaft height area of 200mm (for example, the dry weight of Husqvarna TE300i is 103kg), while the battery pack height of electric vehicle models generally exceeds 400mm, resulting in a 15% increase in the center of mass. According to the simulation of MIS (Motorcycle Inertia Simulator) software, when passing through a 35-degree side slope, the probability of a 110kg electric vehicle overturning is 27% higher than that of a 105kg fuel vehicle. Red Bull Erzbergrodeo Extreme race data shows that the success rate of top riders completing the “Hil Hit” on fuel-powered motorcycles is 18%, while the highest record in the electric category is 9%. Engineering analysis points to the fact that high-quality centers have exacerbated the loss of grip on the rear wheels.