Air filter for all models of the Honda Helix CN250, include many Honda clone 250cc engines used in the gas scooter and go kart world The most notable scooter 250cc clone is the CF Moto CF250 30 Day Warranty Description Air filter for all models of the Honda Helix CN250, include many Honda clone 250cc engines used in the gas scooter and go kart world. The most notable scooter 250cc clone is the CF Moto CF250. The 250cc Honda style engine has become increasingly popular in use on low cost Chinese made go karts and dune buggies. A clean air filter is important in off-road applications. Air intake opening of this air filter is 52-54 mm, depending on where you take the measurement.