Hrm.
Honda made an "Aero 50" little scooter, and several 750s but none "Aero".
In any case, being a Honda we can bet it's 4stroke.
Check your compression. Get a compression tester thingie at any good auto parts store, check for at least 90lb in each cylinder and if there's more than one make sure there's no more than 10% variance between. If gas is getting down into the crank it'll show up in poor ring sealing.