The Honda GX390 engine has a displacement of 389 cm³, an output of 11.7 hp (8.7 kW) at 3,600 rpm and torque of 26.5 Nm at 2,500 rpm. Its dry weight is 31.7 kg. It can also be equipped with an RPM limiter. How fast is a 390 cc kart? As with the GX270, top speed is set by the operator through adjustable speed limitation, within the EN 16230 standard. The GX390 gives the strongest acceleration in the range.

Standard on: Viper Kart
Not available for: Viper Kart Junior