Hello there !
Just bought a 1984 Suzuki GS750E and has an issue starting if its cold the person I bought it off of told me to cover the air box for a second while trying to turn it over, then remove it then start it again. Any clue why its having a hard time to start in the cold. As well when I looked in the air box I noticed it didnt have a air filter could this be an issue with my problem? any help would be greatly appreciatied. Thanks again
Missing an air filter can DEFINITELY be your problem. Some bikes are extremely sensitive to the air/fuel mixture, and when the airbox is opened up the bike is getting way too much air in relation to the amount of fuel entering the cylinder.
First thing I would do if I was you is put in a fresh air filter. I wouldn’t be surprised if it completely cured your problem.