Alright so I am currently working on restoring an old 1979 KE100. So, before i start buying new parts to replace the rusted old ones, i want to see if there are any trouble shooting i can do to see where i should start taking the crankcase apart and replacing things.... so the bike starts perfectly fine and i can keep it running as long as i throttle feed it gas in neutral but it will not idle for more than a second or start running in first. The gas tank is thoroughly rusted and the single cylinder and head is covered in rust. I am not sure if something might be wrong with the needle valve or if the rust in the fuel tank is causing trouble with the orifice tube/fuel valve. I also cant find the idle screw if there is one. but I am pretty sure that is not the problem. Please help!