what are bigger jets
..a jet is the port that fuel, from the bowl of your carburetor, is drawn up thru, into the airstream from your air filter..the fuel is atomized there, and sucked into the combustion chamber of your engine's head thru the intake valve...
..when installing a free-flow air filter and a performance exhaust, you must increase the diameter of your carb's main jet, due to the increased air flow, to keep your fuel mixture from becoming lean...